os An Address De 1B

. the National | a oe Tp. Association Se
_ “at Si nta Barbara, Cal., ee 20; 19 Sp

- LOUIS ie ‘DUBLL De Statistician | =
| Murreoro1.t ITAN v Lae INSURANCE Company, New \ York ae

 
THE CAUSES FOR THE RECENT DECLINE IN
» TUBERCULOSIS AND THE OUTLOOK |
FOR THE FUTURE

By Louis I. Dusiin, Ph.D., STATISTICIAN
METROPOLITAN Lir—E INSURANCE COMPANY.

New York

I. THE STATEMENT OF THE PROBLEM

Tue decline in the tuberculosis death rate during the last twenty years
is, in my judgment, the most outstanding fact in the tuberculosis prob-
lem. This decline has been large in amount and continuous in character.
There has been no backsliding; there has never been any doubt as to the
tendency of the tuberculosis death rate during the last twenty years. In
1900, (and that, by the way, was the first year for reliable statistics on
tuberculosis for any large part of the United States) the death rate was
195.2 per hundred thousand of population. In 1910, the rate in the
same geographical area, namely, the Original Registration States and
the District of Columbia, had dropped to 164.7, or 15.6 per cent., in the ten
year period. In 1920, the rate in the same states was 112.0. This is
42.6 per cent. less than the figure for 1900. In the second decade, that
is, from 1910 to 1920, the rate fell 32 per cent., or a little better than
twice as fast as in the first decade. In 1921, the rate went down to the
low figure of 94.2 per 100,000, which is less than one-half the figure for
1900, only twenty-one years before. The general character of the de-
cline is clear enough and is shown in Chart 1 and Table 1 on page 2.
The straight line expresses the tendency during the period and is the
most convenient expression, mathematically, of what has happened in
the two decades.

Let me leave with you another picture, and that is of a group of some
fifteen million people insured in the Industrial Department of the Metro-
politan Life Insurance Company. Since 1911, accurate records of their
mortality have been kept. Every death is recorded and the number of
persons insured is also.known. ‘There is little room for error in the
calculations. Now, in the year rgit, the rate of mortality for tuberculosis
was 224.6 per 100,000 insured persons. These are working people, mind
you,—men, women and children,—constituted, as to age and sex, about
the same as is the general population. By 1921, the tuberculosis rate
among these people had dropped to 117.4, and in 1922, it declined to
114.2. The decline between 1911 and 1922 was 49.2 per cent. The im-

, 1

 
CHART I AND TABLE I

 

 

DEATH RATE per 100,000-TUBERCULOSIS-ALL FORMS

ORIGINAL REGISTRATION STATES AND DISTRICT OF COLUMBIA,

DEATHRATE
PER 100,000

 
 
  
  
   

190
180
170
160
150
140
130
120
0
100

90

OLt to} jy to} poe pt pep ttt pt | tt |
1900 190! 1902 1903 1904 1905 1906 1907 1908 1909 i910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921
YEARS

Year
1900

ISO!

1902
1903
1904
1905
1906
1907
1908

1909

I910

I900 TO 192I
DATA

Rete Yeer Rate
195.2 (911 159.0
1898 012 49.8
174.1 1913 148.7
77.1 IN14 1486
188.5 I9I5 146.7
180.9 N16 143.8
17.8 17147.
156. = 1918 «151.0
694. = 191s 1249
163.3 1920 112.0
1647 921 942

 

 

SISOTNOWAGNAL NI ANIIONG LNAOAY AHL UOT SasaAVvo

 
LOUIS I, DUBLIN, PH.D. 3

provement is continuing this year and, in the first six months, we have
recorded+a decline of 5.3 per cent. among white policyholders and of 2.4
per cent. among colored from the corresponding figures for 1922. Chart
2 and Table 2 on page 4 show what happened in this group of insured
wage earners.

I have shown you that with reference to the general population, the
death rate from all forms of tuberculosis has declined fifty per cent. in
twenty years, and that in a large group of insured persons, the same
amount of decline has occurred in a little over ten years. The improve-
ment in the figures means that a hundred thousand fewer persons are
dying each year in the United States from tuberculosis than would have
died if the tuberculosis death rate of twenty years ago were still pre-
vailing. That is an amazing fact, and, I believe, justifies my first re-
mark that the decline in the death rate is the most outstanding item in
the tuberculosis problem. -

My purpose, however, is to discuss the causes underlying the decline.
As you know, there is much difference of opinion as to what has caused
the decline in tuberculosis mortality. The first step in a scientific dis-
cussion is to set for yourself a theory or a probable explanation on the
basis of such evidence as is available and then to see how that theory
squares with all the facts of the case. In connection with the decline
of the tuberculosis death rate, there are two out-standing explanations.
I shall consider these two opposing views and attempt to show you
whether or not they square with the facts.

The first is espoused by most of the workers in the field of public
health and ascribes the fall in the tuberculosis death rate during this
period of twenty years and for a long period before to the great im-
provement in the general wellbeing of the population. The improvement
is due, they say, primarily to activities within human control. Those
who hold this view say that the great mass of the population is pretty
generally exposed to infection, and that those who break down and
become active cases of tuberculosis, and later die, are those who have
not had the resistance to localize and control the foci of infection within
them. With that thought in mind, the proponents of this view early
developed a broad campaign of general education of the population. A
knowledge of personal hygiene was widely disseminated in order that
individuals might learn how to strengthen their resistance against the
development of active symptoms of the disease. This was the keynote
of the general campaign against tuberculosis as outlined by this Asso-
ciation when it was founded in 1904.

The campaign against tuberculosis was accordingly directed toward
finding the large numbers of individuals who had broken down with the
disease, to strengthen their resistance and to make them well again if
possible and, second, to prevent their infecting others. That meant, of
course, the establishment of such institutions as the tuberculosis clinic,

 
 

4 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

CHART 2 AND TABLE 2

 

 

Death Rate per 100,000-Tuberculosis-All Forms

Metropolitan Life Insurance Co. Industrial Dept, 1911101922 &
Expanding U.S. Registration Area (aes 1 to74 years) 1911 to 1921 .

DEATHRATE
PER 100,000
225

DATA
Deathrate per 100,000

M.L.I.Co. U.S.Reg. Area
Yeer Indl. — Ages 1°to 74 years
191! 224.6 IS7.6

200

2 2129 14@.G:
13 206.7 «146.5
115
94 2045 14623
915 197.8 145.4
2 16 = 190.2) «141
jo” = 188.9 «145.8
125 18 ~=—«18D9.0—s: 148.6
9 1565 125.2

1920 IS7.9 12.5

 

 

100
192] 7.4 97.7
90
ee eae ee ered ar =
i 12 113 “4 15 16 17 “18 19 *20 ‘ZI i922 ee 14.2
YEARS

 

 

the training of many physicians in the technique of diagnosis, the build-
ing of sanatoria for the care of early cases and of other institutions
for the more advanced cases, and the segregation of those individuals,
who having broken down, might become a source of danger to others.
T need not enumerate all the activities and agencies which have grown
out of this conception of the origin and control of tuberculosis. It is
LOUIS I. DUBLIN, PH.D. o

sufficient to say that all over the world a definite technique for the con-
trol of tuberculosis has been developed on the basis of this theory. This
probably has received its best and most acceptable expression in the
writings and practical works of Dr. Philip of Edinburgh.

The underlying principle of his campaign and of his followers has
been that tuberculosis was subject to human..eontrol. The disease de-
veloped because of infection and the weakened defenses of the individual.
This might be due either to undesirable conditions of the organic and
physical environment or to weakened personal constitution, or to both.
This school did not lose sight of the importance of the constitutional
factor. It realized that there are differences in the capacity of individuals
to resist the development of infection and breakdown. But, it saw that
with respect to the constitutional factor, man could do very little except
to make the most of what constitutional equipment he had. The emphasis
of this group has, therefore, been placed where it could be effective,
namely, in the constant improvement of the status of human beings.
The campaign against tuberculosis has attempted to make the lot of men
and women happier and easier, to improve their personal hygiene, to
remove possibilities of gross infection and to give many individuals a
fighting chance to throw off disease which they would not otherwise have
in their usual methods of life. Acting on this theory, a flourishing and
world-wide activity has developed and those associated with it have very
naturally. claimed that a measure of the decline which has appeared in
this period may be credited to their and allied efforts.

The second explanation or theory minimizes the importance of the
environmental factors in the control of tuberculosis. It places great
emphasis on the fact that the decline in tuberculosis antedates by many
years the development of the tuberculosis campaign as at present un-
derstood, going back, in fact, to the early decades of the nineteenth cen-’
tury. Those who support this second view emphasize the all importance
of the genetic, that is, the constitutional factors. They grant the uni-
versality of infection, but they insist that those who break down are a
special group whose constitutions, in advance, have doomed them to
tuberculous disease. They insist, moreover, that the tendency to have
tuberculosis is inherited like other physical characteristics, and that ob-
servation will discover a distinctively tuberculous stock or phthisical con-
stitution, quite irrespective of the environment, mode of life, or any
effort that man might make either to avoid infection or to build up indi-
vidual resistance.

A corollary of this explanation has been that hardly any of the decline
to which we have called attention could have resulted from the tuber-
culosis campaign. It is not in the nature of the disease, this group says,
to be amenable to the kind of treatment that has been given to environ-
mental factors.There is, as you know, a school of biological writers, who,
for many years have labored to show that the tuberculosis campaign as

 
 

6 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

it has crystallized in official and voluntary agencies, was doomed to fail-
ure. In its extreme form as stated by Dr. Given and quoted by Professor
Pearl of Johns Hopkins University, the view is expressed that “there is
no evidence that anything that man has done has affected in either one
way or the other the decline in the mortality of tuberculosis which has
been continuous for nearly three-quarters of a century.” In fact,
it has been urged that such effort as has been made is likely
to have done more harm than good by encouraging the reproduction
of phthisical stocks and thus thwarting the influence of natural selection.
The decline in tuberculosis, on this view, is ascribed to the influence of
the disease itself as a selective agency in eliminating less fit stocks and
thus preventing the reproduction of such individuals. Possibly, it is best
to quote Professor Pearson’s own statement.*

“Has or has not the selection due to many years of heavy phthisis
mortality left us with a more immune and resistant population? If it
has—and that I believe will be found to be the ultimate explanation of
the fall, especially the retarded fall in the phthisis death rate—then in-
fection is not the only factor worth investigating. There is the question
of hereditary immunity. It may be a bitter pill for mankind to swallow,
when we suggest that natural selection may have done more for racial
health in this matter than medical science, but it may have its compen-
sations from the economic standpoint. Above all, it may suggest that
Evolution helps man better than he at present knows how to help him-
self, and that possibly he would learn to help himself better if he studied
her processes of racial selection a little more closely.”

II. A STATEMENT OF THE FACTS

These then are the two views which, I hope, I have stated clearly and
without bias. The first emphasizes the importance of the environmental
factors in the causation of tuberculosis and credits the improvement in
the death rate to those human activities which have centered around the
amelioration of the environment of the great body of people. The
second emphasizes the importance of stock and ascribes the decline to
secular changes in the germ plasm of nations and of races which follow
from the full interplay of natural forces rather than from the con-
scious interference of man with nature. After all, these are only at-
tempts at an explanation. They have no assured validity unless they
square with the mass of facts. I will, therefore, rehearse some of the
commoner characteristics of the disease, tuberculosis, and shall try to see
how often each of the two views appears to be consistent with or in
opposition to the facts. The factual data are so numerous and often so
clear-cut that we should have little or no difficulty in determining which
of the hypotheses we have outlined has the better of the argument.

*“The Fight against Tuberculosis and the Death Rate from Phthisis.”—pp.
34-35.
LOUIS I. DUBLIN, PH.D. r 7

TABLE 3
Death rates per 100,000 Population in U. S. Registration States
. Tuberculosis—all forms
1917

Urban and Rural Areas Compared*

 

 

 

 

 

 

States Urban Rural

Total Reg. States of 1917.......... 0... cece eee 159.2 130.3
California... 0.0.0 c cece eee tect e eee 179.9 190.1
Colorado... 1. eee ec cence eee eens 250.3 ~ 129.9
Connecticut. ..... 0.0... c ec cece eee eee eens 171.0 155.7
Indiana... .. lee cece cee cece cence eee enee 155.2 133.8
Kansas... cece ccc cee ee eee cece eee ee te eee 82.2 49.6
Kentucky... cece cece eee cece ete e ene ees 227.1 191.1
White... oc cc cece ee ee eee eee ens 168.9 164.7
Colored...........00000ee ee 526.5 462.4
Maine. ...... ccc cee ce tee eee e eee eee ences 144.5 105.5
METH EINE. Soo 000000600000008b500000000000009009 225.5 178.4
White... ccc ce ccc cee cece eee eben eee e eee ence 164.4 144.1
Colored. ....... 0c cece ce ete eee eee eens 596.2 322.9
Massachusetts.....-.......0.eeeee eee “se Poi eee 141.5 152.4
Michigan... 2.1.2... ce cece cece ee eee e rece eens 131.1 90.5
Minnesota... ... 2. cect eee cee ete eee eee eens isle 86.7
MiSSOULL. .. 0. cee ec ce eee eee eens 166.8 134.7
Montana... .. cece eee ccc ce eee eee eee eee es 149.3 105.3
New Hampshire. ........ 0.00. cc ees ee ect eeeee 119.1 107.9
New Jersey... 0. fs eee bee cet eet s essence ote. 138.6 180.7
Ne WaV/on een ne ene Choe cirrnciiiciar: 168.3 131.4
North Carolina. . 00.0.0... cece cece eee eens 271.2 128.1
White eco es cies site aie oes esi edeiele lclelineolrenete enero 196.5 88.0
Colored. ..... cece ec ete ete ee eee eens 402.1 218.0
Ohio ner 167.5 117.6
Pennsylvania............ 00sec e eee cece ete eee 152.9 118.8
Rhode Island........... 0. cece eee eee eens 173.6 113.3
South Carolina... 2.0.0... cece eee eens 249.3 134.6
7 aris cn ee tre 139.2 63.3
Colored... 1... ce ee eee eee eae 384.7 195.3
Tennessee... 1... ec cee tee rete tees 234.2 190.8
White... oc cece cc eee cece eee ee neces 148.6 157.1
Colored. ...... cee eee eee tees 413.5 347.2
ITA; a a re Sr ed atid 52.0 38.6
Vermont........... Be Oe ee ETL 132.0 83.6
Virgitiia. ccc ee eee oe cae ee ee ec eee 194.4 (105.2
AE ee ee ee 128.4 106.3
(GOOG Ce ee 328.3 302.3

> Washington. ..:....c ccc reece eet eer ee ee cee tees 72.4 90.0
ie 3

 

Wisconsin. ......- cece ce eee eet eee eee tenets 102. 96.

 

*The term “urban” indicates municipalities of 10,000 inhabitants or more in 1910, smaller
places being included under the term “rural.”

 
 

8 CAUSES FOR THE RECENT DECLINE IN- TUBERCULOSIS

_ Geographical Variation in the Tuberculosis Death Rate—The first
fact is the great variation in the amount of fatal tuberculosis in various
parts of the United States. Tuberculosis is preeminently an urban dis-
ease. It is, of course, present in rural sections of the country, but to a
lesser degree. The latest figures that we have showing the contrast are
for the Registration States in 1917. In that year, the rate in the cities
was 159.2 and in the rural area 130.3 per 100,000. The Census Bureau
has not published any figures distinguishing between rural and urban
areas since then. We have also figures for each of the states of the |
country showing the distinction between rural and urban groups of the
population. In almost every instance, the rate for the urban areas is
materially higher than for the rural areas. Please remember, also, in
this connection, that many of the sanatoria and hospitals for the tuber-
culous are located in rural areas, and that these civil divisions are usually
charged with all the deaths that occur there, although many of the patients
are city residents. If the necessary corrections were made for original
residence, the difference between the two rates would become all the
more marked in favor of the country. Table 3 on page 7 presents the
data for the urban and rural parts of the Registration States in IQI7,

Then, too, you are familiar with the fact that the death rate from tu-
berculosis is very much lower in some states than in others. The lowest
rate in 1921 is found in Nebraska, namely, 37.1 per 100,000. Utah had
a rate of 39.9; Kansas, a rate of 43.3. Beginning with these minimum
rates, the figures increase gradually until we get to New York with a
rate of 102.4, Rhode Island with a rate of 108.0 and Delaware with a rate
of 140.6. There are even higher rates as, for example, for California
and Colorado, but we realize that these high rates are due in large
measure to the migration of tuberculous persons to those areas. It is,
therefore, unfair to use the last figures in interstate comparisons. But,
excluding these states, the figures, varying from 37 in Nebraska to 140
in Delaware, present a fair range of variation in the states of the country.
(See Table 4, page 9).

Finally, we may note the diverse rates in the large cities of the country.
There is first Akron with a rate of 46.9 in 1921; Salt Lake City, 64.7,
and Grand Rapids, 63.7. Further down the list, we find such cities
as New York with a rate of 104.3, Cambridge, 125.0 and Toledo, 125.3.
At the end of the table, we find cities like Cincinnati, 152.7, and Denver
and San Antonio, with rates above 200 per 100,000. But, the high rates
in the last two cities reflect the concentration of migrant tuberculosis
within their limits. (Table 5, page 11).

Here, then, are our first facts. Let us try to square them with the
two explanations. The environmentalists, although I use that term ad-
visedly, approach this phenomenon of extreme variation in the tubercu-
losis death rate without hesitation. They are familiar with it and have,
in fact, based much of their assurance on it. Those who live in the
country,—the rural population—they say, might be expected to have a

“4
LOUIS I. DUBLIN, PH.D.

TABLE 4

Death rates per 100,000 Population in U, S. Registration States and Area
Tuberculosis—all forms.

 

 

 

1921
Area and States Death rate Area and States Death rate

U. S. Reg. Area.......... 99 .4 iNonthg@arolinasts 9c. ee 104.8
\inite resi ee 69.3
Orig. Reg. States of 1900.. 94.2 @Colotedh a= 187.4
States ranked according Rhode Island Erna iar ire 108.0
Penne rer neOode Mississippi We a eee 111.1
White.................. 49.5
Nebraska 37.1 Colored................. 167.2
Utah. 21s eee 39.9 South Carolina............ 111-2
IKAWIEES . cobb 6h doudone ce 43.3 Vite 52.4
Vortec tc ane 61.8 Goled ee ee 168.0
Vermo eS es 2 cae 69.5 Louisiana.:............... 122.4
Nae Je White .........0..0. 00. 69.4
INIEOB PEER. 5 ooo uscec aoe: 75.2 Colored. ................ 207.2
pie BO a Ba 76.0 District of Columbia ....... 126.6
MN BESOLA fe aaig i 77.0 Une eee 75.2
New Hampshire. ....... 78.9 (Colonedinnne iar ree 278.2
oe oes eee ee 82.1 Kentuckye reer a a 131.2
oa ee 82.7 Whitel. 9.7... 2 110.0
Illinois... 2.1... eee. 84.9 Coles 333.1
a line 89.1 Wineries ee nee 133.4
Pennsylvania Sas ee sane 92.3 Te 86.1
Witte 83.8 Colored. ................ 246.0
+ ee es 333.0 Maryland................. 135.5
MGI a ge ee a White.............0..-. 102.1
NS CUS ae ae Cac 301.8
New So 93.6 Tennessee................. 139.9
BlOn Gay ea ager at he 106.6
Se 62.4 (olonedin sas ea 282.0
ee eee ee 140.6
Tenareene, meres s : California............6. 00. 151.1
Nese 102.4 Colorado.................. 184.6

White.............. 97.7

Coloredhere tae Blea

 

 

 

 

lower rate. They are engaged in more healthful occupations; they live
in less congested places ; they live more normal, happier lives; they enjoy
a larger and better supply of food and lead altogether a more whole-

some existence.

Those who live in cities, on the other hand, are in

more congested quarters and, therefore, more subject to infection; they
are often engaged in industries which are more distinctly hazardous to
general health; they are on the whole poorer and less well supplied with

 
 

10 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

good food and fresh air. Life is harder and more hazardous in the
cities and there are more chances for the natural resistance of the in-
dividual to break down.

They explain the differences in the rates in the various states and
cities in much the same way. They stress the fact that often those
places which have the lowest rates excel in their efforts to make life
better. Some are the states and cities where the people are most intelli-
gent and prosperous, least crowded and driven in their efforts to make
a living. Often they are the centers which have deliberately made the
greatest effort to meet their tuberculosis situation by providing adequate
facilities for the care of the sick and for the education and protection
of the well. The geographical differences in the death rates reflect for
the most part, the environmentalists say, the differences in the arrange-
ments which the communities have made to make life in them happier
and better. |

The geneticists or the constitutionalists, on the other hand, have not
made much of the facts of geographic variation, and it is difficult to
summarize the views that they hold in explanation of these facts.
Obviously, it would be necessary for them to assume that the differences
in the death rates represents differences in the innate stocks with various
degrees of immunity or resistance to tuberculosis in the several parts of
the country. They are compelled to posit a hierarchy of constitutional
vigors corresponding to the low rates and the high rates. They must
assume that the population in the rural areas is constitutionally better
selected than that in the cities; that the population living in Nebraska,
for example, is a fitter population than that living in Delaware or in
New York; that the people living in Akron are innately more vigorous
than those living in Providence. Without any desire to prejudge the
case from this single line of evidence, it must be clear, I think, that on
the score of variation of the death rate, the environmentalists have very
much the better of the argument on the first count. Their assumptions
are consistent with everyday observations of the differences in the modes
_ of life and in the general level of wellbeing in the various parts of the
country. Their explanation does not add difficulties which in their turn
need expounding. But, the explanation of the second group has simply
substituted one difficulty for another. There is no warrant in fact for
any such degree of difference in our races and populations as their theory
would demand. The people of the various states and cities are, with a
few outstanding exceptions, altogether too much alike in their inherited
qualities and their race histories to explain the enormous differences we
have described.

Sex and Age Variations.—But, of course, geographical variation is only
one and the first test. Another fact about the tuberculosis death rate
which is almost universal, is the marked difference in the death rate in
the two sexes. Tuberculosis mortality is much higher among males than

‘
Death rates per 100,000 Population.

LOUIS I. DUBLIN, PH.D.

TABLE 5

Tuberculosis—all forms.

11

U. S,. Registration Cities in 1921

 

 

 

 

City Deathrate City Deathrate
Akron................. 46.9 Wilmington (Del.) ......... 106.7
Salt Lake City ......... 61.7 Buffalo................... 110.7
Grand Rapids.......... 63.7 Houston.................. 114.4
Portland (Oregon) ...... 64.2 White.................. 93.3
Spokane............... 64.2 Colored................. 180.5
Rochester.............. 67.8 Philadelphia............... 115.7
Syracuse............... 69.9 Boston................... 116.4
Milwaukee............. 70.0 Albany................... 117.4
Seattle..............5. 70.7 Atlanta. ..........5.22.... 119.0
Reading............... 72.4 White.................. 65.0
Oakland............... 73.3 Colored. ................ 239.0
Hartford.............. 73.9 Kansas City (Kan.)........ 119.4
Springfield (Mass.)...... 76.5 VAMIDIEBs S 5 S'o Gav oae ec ound 76.7
Scranton.............. 77.0 Colored i saan 367.3
Omaha................ 77.1 New Bedford.............. 124.0
Youngstown........... 80.1 San Francisco ............. 124.5
New Haven............ 80.9 Indianapolis............... 124.7
Camden............... 81.1 White.................. 101.1
Newark............... 81.1 Colored. .............0.. 310.0
Lowell................. 82.7 Cambridge................ 125.0
Minneapolis............ 84.7 Toledo... -........5-5.42. 125.3
Ghicasoue an 85.0 Washington, D. C.......... 126.6 |
Dallas................. 86.5 White.................. 75.2

White............... 54.8 Colored................. 278.2
Colored............. 270.4 Louisville... ............. 131.7
Jersey City............ 86.9 IME SO oS SS bs 9 0 aco 98.9
St. Louis.............. 87.4 Colored. ................ 292.7
Dayton................ 89.8 Baltimore................. 139.5
Detroit................ 89.9 White.................. 96.3
Trenton............... 90.5 Colored. ................ 388.1
Columbus.............. 93.2 Birmingham............... 145.1
Fall River............. 96.9 White.................. 52.2
Cleveland.............. 97.9 Colored. ................ 288.6
Providence............. 98.0 Richmond................. 145.2
St. Paul............... 98.8 White, ..........5...... 91.5
Bridgeport............. 99.0 Colored. ................ 264.9
Kansas City (Mo.)...... 99.7 Cincinnati................ 152, 0
Paterson.......... ae 101.9 Nashville................. 159.0
Pittsburgh............. 102.5 White.................. 95.6
Yonkers............... 102.6 Colored. ................ 309.0
Worcester.............. 102.7 Memphis................. 168.9
New York. ............ 104.3 White...............0.. 80.8
Queens.............. 77.5 Colored. ................ 317.8
Bronx............... 86.6 Los Angeles............... 173.4
Brooklyn............ 88.3 New Orleans.............. 189.8
Manhattan .......... 128.0 White.................. 136.2
Richmond........... 154.2 (Colored aan nar 341.4
Norfolk. ............... 105.6 Denver................... 219.2
White............... 51.5 San Antonio............... PIV)
Colored. ............. 194.8

 

 

 

 
 

.12 CAUSES FOR THE RECENT DECLINE IN -TUBERCULOSIS

among females. Among the policyholders of the Metropolitan, (and
similar conditions are found in the general population of the United
States,) the death rate among white males during the period 1911-1920
was 36 per cent. higher than among white females. That is for all ages
combined. Among the colored, the excess of the male over female mor-
tality in the same period was 8 per cent. But, let us analyze these figures
a little with reference to age. In Chart 3, page 13, the solid line shows
the death rate from tuberculosis among males in the various age periods
of life beginning with early childhood, increasing by five-year periods
so old age. The broken line illustrates the facts for females. The
aggregate, that is, taking the whole of life together, shows, as I have
said, an excess of tuberculosis deaths among males. But, if we keep in
mind the age element, the picture is somewhat different. In the first
two age periods of life, up to the age of ten, the rates are so nearly the
same that there is no point in making a distinction between the sexes.
Beginning with age ten, the rate for females is higher than for males,
and that continues for the next fifteen years of life up to age twenty-five
for both the white and the colored groups. The excess of female over
male mortality is, moreover, considerable. Beyond age thirty the rate
for females drops rapidly and continues throughout the rest of life below
that of males. The white male rate reaches its maximum at about age
forty-two years and is then 477.2 per 100,000: the white female rate is
highest at about twenty-seven, when it is 240.2 per 100,000. The curves
for the two sexes are clearly very different. The excess rate of males is
limited to the ages beyond thirty, while the females show an excess at
the younger ages. ;

How do the two explanations square with this fact? The environ-
mentalists would say that the boys and girls in our country are pretty
much the same as to exposure and as to resistance. The higher rate for
females at the ages of adolescence and early adult life they would explain
on the assumption that at this period, developmental changes in the
organism involve greater hazards than among males. The intense in-
ternal changes that accompany puberty and the mechanism of develop-
ment to maturity in the female are sufficient, they say, to explain their
lower resistance. The hazard of childbearing must also be considered.
Pregnancy is often fatal among those who have incipient tuberculosis,
and many breakdowns are traceable to the first childbirth. Moreover,
in the last twenty years, a large and ever increasing number of young
women and girls have gone into gainful occupations, remaining at work
for greater or lesser periods and sharing with men the hazards of work,
though possibly less well equipped for such strains.

In any case, the change in the sex-ratio of tuberculosis mortality comes
at about the twenty-fifth year of life, and thereafter females enjoy
decided advantages. Fewer of them are engaged in industry with the
hardships of factory routine; they lead’a more regular and sheltered
13

LOUIS I, DUBLIN, PH.D.

Cuart 3

 

Death Rates from Tuberculosis-All Forms
Males and Females Compared by Color

METROPOLITAN LIFE INSURANCE CO.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INDUSTRIAL DEPARTMENT
Pe 00000 1911-1920
500
400 7 NX
00 Vi WHITE bo
° ie, Soe aN
J |e ow ey ha, i N
200 ef “hee ‘J
4 a
/ Se
4 Sma st OP tame ae oy can es fs a
Jf 2A eae aa BO
100 ;
4
=
O
I-4 5-9 10-14 15-ID 20-24 25-29 3034 3539 40-44 45-49 5054 55-59 60-64 65-69 70-74 156 over
625 oars
600 i X
: X
500 f fs a iat |
: =. NY
H x el |
400 i we oe
,
H I ML >
300 y “
mh | re <
a
200-48 fae m= J. a
; / FEMALE ue cme ax =e axe gy oo 4
Lo
100
0

 

 

 
 

14 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

life; they indulge in fewer excesses, have better habits, and take better
care of themselves. For these reasons, those who hold the first view
would expect to find the facts with reference to the death rate in the
two sexes very much as they actually are.

On the other hand, those who sponsor the theory of the constitutional
factor in tuberculosis causation must explain the changing relationships
of the death rates in the two sexes with advancing age. They must
assume a difference by inheritance, or by selection, in favor of males at
the younger ages and in favor of females at the older ages. There is
no evidence for such differential hereditary endowment among brothers
and sisters. I should say, however, that they have at no time, to my
knowledge, addressed themselves to this problem or attempted to explain
the phenomenon.

Racial Variability in the Tuberculosis Death Rate—The third outstand-
ing fact in a description of tuberculosis is the marked difference in the
rate of mortality which prevails in the various nativity groups composing
the population of the country. In a previous study, I have shown how
different is the mortality from this disease in the six or seven principal.
stocks that constitute the population of the States of New York and
Pennsylvania.* The figures are so clear-cut and so much the same in
the two states studied that I would expect to find a similar situation to
exist generally throughout the country. Table 6, page 15 shows the
facts with reference to the mortality from tuberculosis for males and
for females respectively.

In general, we found that the death rate was lowest among those -
born in Russia, who, in these two states are for the most part Jews.
This interesting fact has been observed again and again not only in the
United States but in other parts of the world where the mortality of
Jews has been carefully studied in comparison with that of their neigh-
bors. Tuberculosis does not appear to be as fatal among them as among
other races. The disease when it appears is more often of long duration.
The rates are also very low among the Italians. In fact, at some age:
periods, the rates were actually lower among those born in Italy than
among those of Russian birth. The Austro-Hungarians, who in these
two states are also often of Jewish extraction, show very low rates.
These three nativity groups at many of the age periods show lower
tuberculosis rates than those for the native whites. The native whites,
on the whole, present an intermediate position between these three
nativity groups and those born in Germany, Great Britain and Ireland.
The highest rates are found among both males and females born in
Ireland. This is more especially true in New York than in Pennsylvania,
but in both states, the conditions in this race are notoriously bad. In

* The Mortality of Race Stocks in Pennsylvania and New York—by Louis I.
Dublin and Gladden W. Baker. Reprinted from the Quarterly Publication of
the American Statistical Association, March, 1920.
 

Comparative mortality from pulmonary tuberculosis

ce)

TABLE 6

(ax)

of different race stocks in New York and Pennsylvania, 1910

 

 

SEX AND AGE

DEATH RATE PER 100,000 LIvING AT SAME AGES OF PERSONS BORN IN

 

England, Scotland

“United States

 

 

 

PEEIOD Austria-Hungary Russia Italy Germany and Wales Ireland (whites only)
Pennsyl-| New j|Pennsyl-| New Pennsyl-| New j|Pennsyl-| New j|Pennsyl-| New | Pennsyl-}| New Pennsyl-| New
vania York vania York vania York vania York vania York vania York vania York
Males:
All ages..... 118.0 | 166.0 | 107.4 | 114.7 81.5 | 112.1 | 194.9 | 267.4 | 150.2 | 215.2 | 342.8 | 589.3 | 105.1 | 170.9
Under 10....} 13.8 16.7 15.4 23.5 19.9 8.3 | 147.9] ..... 23.4) ..... ] ..... 23.3 23.4
10-14....... 3515 14.1] ..... 11.7 25.0 LSet nee 52.8] ..... 36.9] ..... ] 22... 11.2 10.2
15-19....... 55.4 | 102.4 69.6 60.5 43.4] 106.8] ..... 90.8 | 120.3 | 128.7 | 428.0 | 312.3 61.1 | 101.5
20-24....... 106.5 93.1 99.6} 96.4 86.5 | 140.4 | 211.3 45.9 59.3 71.5 | 127.7 | 327.3 | 147.6 | 216.3
25-44....... 110.6 | 177.2 | 105.9 | 117.1 71.2 | 102.0 | 198.2 | 252.5 | 151.5 | 240.5 | 375.8 | 662.9 | 185.2 | 352.0
45-64....... 264.2 | 302.5 | 225.1 | 246.4 | 154.3 | 172.9 | 230.3 | 350.0 | 165.3 | 268.9 | 408.8 | 682.1 | 174.1 | 262.1
65-84....... 242.7 | 247.9 | 148.7 | 182.4 | 631.8 | 208.5 | 140.6 | 211.3 | 233.5 | 210.3 | 206.1 | 329.3 | 189.3 | 161.4
85 and over ..]| ..... | ..... | ..... | oo... 180.2 | 210.7] ..... | ..... 357.6 | 60.0] 69.3
Females:

' Allages..... 130.2 | 102.6 91.7 74.6 | 102.2 | 160.1 90.4 | 115.3 | 133.2 | 123.3 | 201.2 | 276.1 98.8 | 109.6
Under 10.... 27.4] .... Sie® | vo0c 42.0 34.0] ..... 51.7 41.6 2S Rie ees ere 19.1 20.6 ~
10-14....... 17.3 Id |l-con'oe 5.7 | ..... 89.1] ..... | | a2. | 13871 19.3 27.1
15-19....... 74.2 49.6 70.9 28.0 | 102.0 | 220.6 39.1 76.9 84.4 64.0 63.6 | 185.6 91.5 | 111.5
20-24....... 141.2 87.9 92.6 88.7 | 153.6 | 247.7 | 128.0 | 158.2 80.4 | 121.5 | 121.6 | 167.7 | 162 3 | 186.3
25-44....... 152.7 | 137.2 | 108.0 | 104.7 | 114.8 | 159.3 | 106.2 | 125.1 | 166.9 | 165.4 | 235.3 | 353.4 | 172.8 | 193.3
45-64....... 162.3 | 122.9 | 124.6} 80.8 77.7 | 123.3 85.4 | 109.7 | 112.2 | 92.1 | 220.7 | 250.1 | 108.9 | 111.1
65-84....... 215.7 | 142.1 | 178.7 94,3 | 217.3 55.4 72.9 | 106.3 | 153.7 | 139.3 | 140.9 | 192.1 | 178.7 | 137.9
85 and over ..]| ..... | ..... | we... | wee ee | wee 793.7 | 156.7 | 80.3 | 314.5 | 164.5 | 148.6] ..... 100.9 | 32.6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

‘THd ‘NITANG ‘I SINOT

ST
 

16 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

fact, at some of the age periods, the Irish males have as high tuberculosis
death rates as have been found to occur among colored males. I would
refer you to our fuller paper for the details, but here it is sufficient to
observe that there is a real and marked difference between the various
races much more in evidence among males than among females.

It is difficult for anyone confronted with these facts to escape the
conclusion that an inherited racial immunity is a factor in the development
of tuberculosis. Certainly, everyone must recognize that, with reference
to such races as the Jews and the Italians, there is a constitutional
zesistance to tuberculosis and that among the Irish, there is a peculiar
susceptibility to heavy mortality. The differences in economic status
and modes of life are probably not sufficient to explain the extreme
divergencies we have observed. This is clearly a count in favor of the
second or genetic explanation for the development and decline of tuber-
culosis and those who favor this view have not been slow to emphasize
this important fact in developing their argument. On the other hand,
there are certain allied facts to be considered which throw additional
light on this interesting phenomenon. The rates among the Jews and
the Italians are not everywhere uniformly low, but show considerable
variation from place to place, reflecting, in fact, the better and worse
conditions among which the Jews and Italians of this country live. Thus
Drolet, of the New York Tuberculosis Association, has shown that the
Jews living in the various parts of New York City have markedly
different tuberculosis death rates, varying from 83 per 100,000 in the
old and congested downtown Gouverneur District to 52 per 100,000
in the newer and more open Bronx-Tremont District. Although the
people are racially the same, the conditions of life are much more favor-
able in the newer sections of the city. Environment plays its part to
color the racial picture. So, too, the high rates of the New York City
Irish are markedly higher than the figures for these people in their
native country, in fact often twice as high. Here, again we see the
secondary effects of environment. The Irish immigrant is a crowded
city dweller suffering from all the hardships of congested and im-
poverished city life. In the old country, they were, a the most part,
rural dwellers. And, so, admitting the importance of the constitutional
factor in the racial picture of tuberculosis, we must not lose sight of
the equally great bearing of the environment within which the individual
races live. While one race may enjoy an advantage over another with
respect to tuberculosis, it is still capable of having higher and lower rates
consistent with various modes and stations of life. In other words, in
spite of the racial limitation, it is entirely possible for any people to
modify a natural tendency to a high or a low rate through the develop-
ment or neglect of safeguards which hygienic living apparently makes
possible.

Variations in Economic Levels-—Another important fact in our dis-
17

EO (Cp See epee) Ons le eee rele)»

cussion is the difference in the tuberculosis death rate in the various
economic strata of the population. I have at my disposal a series of
death rates for tuberculosis in three main groups of the population;
first, for Industrial policyholders of the Metropolitan Life Insurance
Company; second, for those who are insured in the so-called Intermediate
Branch of this Company; and third, for those who are insured in the
Ordinary Department. These three groups are sharply differentiated
economically. The death rates are as follows: Let us take the age
period 20 to 24 as an example. Among white males in the Industrial

TABLE 7

M ortality Rates from Tuberculosis—All Forms—Per 100,000 Exposed at Specified
Age Periods. Males in Several Departments of Metropolitan Life Insurance
Company and in U. S. Registration States, 1921.

 

 

 

 

 

 

 

M. L. I. Co. males
Age Period U.S. Reg. States
Industrial* | Intermediatef| Ordinaryt Total males
Department Branch Department
White lives | Total males | Total males
All ages—one and
OVEr .........-- 99.5 107.0 68.2 101.0%
Allages—15 to 74.. 157.4 109.2 68.4 133.9
Lto 4........ 35.8 38.2
Sto 9........ 15.2 15.8
10to14........ 14.6 er ee 16.1
15to19........ 02.5 101.7 54.5 63.6
20to 24........ 142.8 89.8 61.5 133.9
2 ELOnS + Pee ee 160.2 109.2 69.5 137.8
35 to 44........ 207.4 100.9 64.9 143.1
45 to 54........ 215:5 133.4 74.1 145.6
55 to 64........ 203.9 163.4 83.1 158.0
65 to 74........ 192.9 158.4 98.0 165.9

 

 

 

 

 

*Death rates {Claim rates tAges one to 74

Department the rate in 1921 was 142.8; in the Intermediate Department,
89.8, and in the Ordinary Department, 61.5 per 100,000. The other
age periods show exactly similar relations. The highest rates are found
uniformly in the industrial group. The intermediate rates are found
in the Intermediate group and the lowest rates in the Ordinary group.
The economic status influences, as we see, the incidence of tuberculosis.
As you go from lower to higher levels of economic wellbeing, the rates
go down uniformly. There is, however, this striking and instructive
exception, namely, that economic status makes no difference in the ages

 
18 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

of childhood and adolescence. The children of the industrial population,
i.e, of the working people, have lower rates for tuberculosis than exist
in the general population. After age 20, the two sets of figures cross,
and thereafter, the rates are lower for the general population than for
the Industrial. The difference becomes greater with advancing age.
(See Table 7; page 17). |

How shall this set of facts be explained? The environmentalists rest
their case on the hardships of the life of the poor as we have already
intimated; the constitutionalists on the superior endowments and vigor
of the selected or “fit” groups who make up the well-to-do and richer
classes of the community as distinguished from the poor. But, how about
the children? The figures would indicate, say the health workers, that
the youngsters of the industrial classes are very well endowed, indeed,
if their lower rates are an indication of their power of resistance. - Is
not this consistent also with everyday observation? Does not this fact
indicate, they say, what one would suspect from other sources—that the
working classes do not lack natural resistance? They do harder work,
over longer hours and show in every way that innately their bodily vigor
is no less developed than that of their better-off neighbors. But, con-
stitutions are apparently not sufficiently ironclad to withstand without
injury for long periods the wear and tear of modern industry. However
good the initial endowment, long hours of toil in confined places often
poorly ventilated, and only too often laden with dusts and poisons, the
strain of attention to fast moving machinery, the effects of heat and the
exhaustion of muscular energy, all finally tell. To these must probably
be added the effects of frequent improper and inadequate diet, sub-
standard housing, indifferent medical service and lack of opportunity for
rest and recreation which are associated with the life of the poor. It is
for this reason, as the environmentalists point out, that the industrial
classes show higher rates and they do not begin to show them until the
effects of their constant environment have begun to tell.

Occupation in Relation to Tuberculosis —The incidence of tuberculosis
in various occupations also throws light on the nature of the disease,
on how it may be caused and how it may be controlled. I have already
pointed out that those who are engaged in industrial processes show
uniformly higher mortality rates than the general population of com-
parable.age periods. This fact is strikingly brought out in the much
lower death rates of females than of males during the working ages of
life. But, even within the male sex, there is much variation among the
several industries atid occupations in which people are engaged. This
fact has a long time engaged the attention of students of the disease,
and an extensive and instructive literature has developed. The results
of investigations have been so consistent and clear-cut that occupations
have actually been graded in a series as to whether they are conducive

 
LOUIS I. DUBLIN, PH.D. 19

TABLE 8

Comparative Mortality from Phthisis among Males, Ages 25 to 65.
Selected Occupations, Compared with Farmers. England
and Wales, 1910, 1911, 1912 Combined.

 

 

 

Per cent deathrate in
Ss
OCCUPATION aa hi s i fee
among farmers
Farmers, graziers, farmers’ sons, etc............-...00-- 100.0
Railway engine drivers, stokers, cleaners............ 100.0
Motor car, motor van drivers...............-eeee eee 105.3
Builders. 20. Lo eee ccc ccc ce ccc cee c eee eeeeees 121.1
Agricultural laborers, farm-servants..............--. 124.6
Brick, plain tile, terra-cotta makers................. 128.1
Iron-miners, quarriers..........seec cece e eee e eet ee, 128.1
- Engine- drivers, stokers, firemen

(not Ry., Marine, agr., or elec. supply).......... 133.3
Coal miners.......... mise te Seal nciewies one ecco case 133.3
Shipbuilding. 2... coe cc cece ec teen eee 166.7
All shopkeepers... 0... 0... cee ccc cette tee eens 205.3
Cotton... manufacture... facees ec cca ccc ce eis mendes 210.5
Wool, worsted manufacture............0.. eee cee eee 217.5
Domestic coachmen, grooms.............. eee eee eee 217.5
Bricklayers... 0 00 cas cea cede ccc cece nee ees cen ees 224.6
Carpenters, jOINers....... cece eee cee eee ee ees 224.6
Engine-, machine-, boiler-makers, fitters, millwrights.... 231.6
Copper workers, coppersmiths..................005. 256.1
Painters, decorators... .ecceceeececceeecceececcecce. 268.4
Clerks. 00. ce ccc cece cee c cece esse esereevecsceserns 270.2
Brewerss 60. Gulch ob aigbin 6 baba ac tae e en ne ebebe sities 317.5
Furriers, skinners............0.ceceeeee cues ie ee 319.3
UEele GE © 15 peremrers ree nd rennet se rn rane da 321.1
Glass manufacture... .... 0... ccc cee ce eee eee eee 322.8
Pailorss . 2. Gee ac wise rss ee eesnte sews: ee eee 328.1
Watch, clockmakers, YON O25 oso pooh co sacco0 coe 328.1
Hotel keepers, publicans, spirit, wine, beer-dealers... 347.4
Printers. 6 65 0. oo ee 0s cw ds ven eve vec edawesseuss 368.4
Shoemakers. .. 1 ccc cece cece weet ee cee eb oe eae oe 389.5
Brass, bronze workers, founders, finishers, workers. 408.8
Stone- getters, dressers, PS OTS eee ee en eee 415.8
Seamen, etc. merchant service..................0.-. 456.1
Group of laborers............-2+-- see e eee e cree, 461.4
Potters-earthenware, etc. manufacture............... 494.7
Lead miners. . 100. we. ccccecc ec cee cee cee ee eenes 587.7
Stone-getters, dressers, masons (counties producing

sandstone). 8) oie eS Eile Cre Ano othe este aise oes 728.1
Costermongers, hawkers.........s+ssceseeeseceeeee. 738.6
Bariméne sc... ose d ose out eee ede ete sec decane 761.4
File makers. 2... woe cece cc ce ccc ee tee eens 761.4
Cutlers, scissors makers.......................00005 817.5
Tin miners... 1. cece cee ccc eee tee eee ees 1200.0

 

 

 

 

to the development of tuberculosis or not. On the whole, there is general
agreement in the data for the several parts of the world.

Leaving out the professional group in order to avoid the complication
of better economic status and other factors which might condition the
result, and limiting ourselves to the fairly homogeneous group of wage
earners and farmers, we find that the best conditions occur among those

 
20 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

engaged in agricultural pursuits. The tuberculosis death rate of this
class of workers we may designate as our unit of measure. The other
occupations may then be graded on the basis of the percentage which
their tuberculosis déath rate bears to that of agricultural workers. The
table of occupations, (page 19), is selected from the report of the Regis-
trar General for England and Wales for the years 1910, 1911 and 1912.

This table discloses a number of surprising relationships. Coal miners,
who are engaged in fatiguing work and are exposed to dust, appear
close to the best group. This phenomenon has, for many years, engaged
the attention of tuberculosis investigators. The great mass of open-air
workers on the railroads show extraordinarily favorable tuberculosis.
rates. In the complete list of the Registrar General, there are no less
than 26 occupational classes which show a mortality from phthisis
almost four times as great as farmers. Very high figures are shown for
occupations exposed to hard metallic and mineral dust, such as, lead
miners, with almost six times the farmer rate; file makers, with over
seven times. as much; and cutlers and scissors makers with over eight
times. At the end of the scale are the tin miners with a rate twelve
times the farmer rate. But such non-industrial occupations as barmen
and seamen compete with the high figures already quoted.

The general conclusion drawn by most students of the relation of
tuberculosis to industry has been that the highest rates are found among
those exposed to mineral and metallic dusts; next to these are the occu-
pations exposed to the use of alcohol, and then those who are exposed
to lead. Certain occupations with exposure to the hardships of weather
and occupations with exposure to organic dusts also, are generally found
to have a high frequency. Investigation of the factors which enter into
the lives of the various classes of industrial workers does not seem to
indicate that high and low rates are always the direct influence of the
occupation, but are often: coupled with the mode of life and the home
environment of the individual workers. Eliminating the very worst
occupations, and limiting their observations to the great bulk of factory
occupations which are neither dusty nor otherwise especially injurious,
but nevertheless present high rates, Dr. Collis and Greenwood offer the ©
following explanation: “The role of the factory is, by confinement in
monotonously ventilated rooms and by causing general fatigue, to reduce
the resistance of the operative to those sources of infection to which he
is exposed in the natural course of life, to make him react more sharply
to home influences than does his wife or sister.”

For us, the important point is whether the evidence we have presented
is more consistent with the one or the other of the two explanations as |
to the causation and the decline of tuberculosis which we are discussing.
The theory of the geneticists would demand that those who are engaged
in various occupations are selected somehow in accordance with their
various grades of resistance and inherited ability to withstand tubercu-

 
LOUIS I. DUBLIN, PH.D. at

losis. Some occupations undoubtedly attract weaker individuals. I doubt
very much, however, whether such an explanation would apply to any
considerable number of occupations we have listed. Obviously, many
of the occupations with the highest rates call for workers with the
greatest vigor. On the other hand, the effect of the industrial environ-
ment on the life of the worker is very clear-cut, even if often marked
by the influences of economic condition, grade of intelligence, and other
elements which affect life. The enormously high tuberculosis death rate
of tin miners and of stone cutters is very clearly the result of the injury
done to the lung tissue by the material with which they work. This is
an extreme picture, but it points to the explanation which underlies the
conditions in other occupations where the hazards are not so extreme or
clear-cut, but, where just the same, the effect of the occupation makes
itself felt. It makes little difference in the long run whether it be fatigue
or monotonous employment, or the effect of vitiated atmosphere which
breaks down the resistance of the individual and makes him an easier
‘and earlier prey to the development of tuberculous disease.

Recent Changes in the Tuberculosis Death Rate.—Finally, we shall
consider the changes in the tuberculosis death rate in recent years, both
in this country and abroad, to see if in any way we may be able to throw
light on the nature of the disease and to determine whether the facts are
more or less consistent with one or the other of the two theories which
attempt to explain its causation and the method of its control. As we
have seen, the tuberculosis death rate in the general population of the
United States has fallen 50 per cent. in a twenty year period. In the
special but large group of insured lives, the same amount of reduction
has been observed in a ten or eleven year period. In more recent years,
since 1918, declines of as much as 10 or more per cent. per year have
occurred. The decline, moreover, has not been uniform in all the groups
of the population, but has favored males more than females, white lives
more than colored lives, and certain definite age periods more particularly
than others. We find, for example among the insured lives where this
phenomenon has been carefully studied, that white males showed a
decline of 55.0 per cent. in the ten year period between 1911-1912 and
1921-1922, as contrasted with a decline of only 41.5 per cent., in the same
period for white females. Table 9, page 22 presents the details, which
are also shown in graphic form in Chart 4, page 23.

The chart on page 23 shows the above changes in sharp relief. With
this evidence in mind, one would be tempted to deny that the type of
age incidence in tuberculosis has any marked stability. Certainly there
can be no ground for the conjecture of Dr. Brownlee that the contour
of the curve for age indicates the existence of three distinct types of
tuberculosis, namely, a type chiefly affecting youth, a second affecting
persons in middle life and third, a type attacking persons in old age. The
facts for the four classes of Industrial policyholders, as shown in Chart

 
22 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

4 and which are perhaps accentuated examples of what has occurred in
the general population, leave us convinced that tuberculosis is not a slowly |
changing condition with fairly fixed characteristic of sex, color and age
incidence, but a more fluid phenomenon responding quickly and incisively
to external modifications when these are properly chosen and well directed.

Of greatest interest is the fact that the maximum decline occurred
among white males in the period between 20 and 45 years of age, where
the decline approximated 50 per cent. The greatest decline has occurred
where the rates were originally highest and least where the rates were
lowest. There is a close association between the amount of decline and

TABLE 9

Percentage decline in Deathrate from Tuberculosis—all forms.
IQ2I-1922 since I9QII-I9I2,

By Color, Sex and by Age Periods

Metropolitan Life Insurance Co. Industrial Department

 

 

 

 

 

 

 

 

 

 

Total White Colored
Age periods ee
: Meet Lea Males Females Males Females

All ages—1 & over 47.0 55.0- 41.5 43.1 33. 1
lto 4 56.4 DoE, 56.4 55.7 49.4
atoms) om 45.1 58.7 47.7 55.8
10 to 14 36.5 39.0 31.1 33.5 34.9
15 to 19 31.8 43 .4 21.2 32.1 28.6
20 to 24 35.1 47.9 28.5 38.9 17.8
25 to 34 51.4 61.2 46.4 47.1 29.4
35 to 44 57.2 63.9 53.0 50.2 43.2
45 to 54 47.2 50.6 42.5 45.3 35.4
55 to 64 43.7 44.3 41.4 42.4 36.6
65 to 74 29.2 25.9 33.5 29.0 9.1
75 & over 38.2 29.3 42.4 3.3* 58.9

 

 

* Denotes increase.

the excess of the death rate in the earlier periods. Of equal importance
is the fact that, in the general population, especially in the large cities,
the most marked reduction in the tuberculosis death rate has occurred
in the period of early infancy. In the City of New York, the decline
in the tuberculosis rate in ten years in the period under age one was
53 per cent., as compared with a decline of 40 per cent. at all ages.

On the other hand, the same years which experienced the remarkable
decline in the death rate in the United States saw on the Continent of
Europe an equally decisive rise in the death rate. Incidental to the war
and to the miseries which resulted from it, the death rate from tuber-
culosis in virtually all the countries of Europe rose to heights equalled
only in the years before the tuberculosis campaigns. All the gains of

 
~LOUIS I. DUBLIN, PH.D. 23

Cuart 4

Death Rate per 100.000 fom Tuberculosis-A\ll Forms

Periods I9II-1912 compared with I921-1922 by
Color, Sex and by Age Periods. .

METROPOLITAN LIFE INSURANCE COMPANY,
INDUSTRIAL DEPARTMENT.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DEATHRATE
PER 100,000
300
A a
ny AN
/\% r“ \
500 Taman 250 ; “wy WHITE FEMALES —~
ye \ I N
y NM ! \
j ‘ | \
400 7 ‘ 200 t ‘
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/ ‘ I \ 7
f N ! \ A
300 Z \ 150 tot
\ I
i \ I /
200 f —| = 4 100 if aw fines
i) i > ae
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I
100 7 WHITE MALES }—. sory :
\ / / . \-4
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0 .
14 5-9 10441519 2024 2534 3544 4554 5564 6574 Dé over +4 59 WH 519 2024 2534 3544 4554 5564 65:74 15 & over
5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

G2 100
600 i nA | | |
|} Ne 7 NN
i . \ 600 4+ COLORED FEMALES }—
500 f XS I %
! tS ! / \ \
4 ~s. 500;-4—44 N
400 a : / \
I JON | \
I l 400 i X
i \ ! \ \
300 I l 1 \ \
q \ y \
\ —_ Le \ 300 7 \ I
oi \ weed te l
200}+++ # \ / \ —s 1
vy 200 iF creat
1 Y N ‘/
\ Pe
100 COLORED MALES —+—] \
0 | | | . 0

 

 

 

 

 

191-1912 = aemne 192\-1922 =

 
24 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

twenty-five or thirty years were apparently lost in the three or four
years of war and in the periods of stringency immediately thereafter.
In the German cities with populations of 15,000 and over, the death rate,
which in 1913 was 157 per 100,000, rose in 1918 to a maximum of 287.
Individual cities like Vienna and Warsaw showed much worse conditions.
In 1913, the rates for tuberculosis in these two cities were 302 and 306
per 100,000 respectively. By 1917, at the height of the war, these fig-
ures had risen to 425 for Vienna and 840 for Warsaw, declining in 1920
to 405 and 338 per 100,000 of population. Cities which, like Belgrade,
passed through long periods of military occupation and food stringency
showed maximum rates, rising even to the horrifying figure of over
1,400 per 100,000 during 1918. But the high rates did not continue
following the resumption of industry and the return of fairly normal
conditions. The most recent figures show that the death rates from
tuberculosis are back approximately where they were at the beginning
of the war and, in some countries, they have fallen to figures well below
those recorded prior to 1914. The picture with regard to tuberculosis
in the European countries is, however, too well known to require any
marked elaboration in this address. How shall we interpret these inter-
esting facts both in the United States and abroad? They are no mere
chance occurrences, covering as they do so large a group of people and
being so different on both sides of the ocean. The figures are just as
instructive as to the nature of the disease as are any of the demographic
items to which we have already directed attention. How do they square
with the two explanations we have considered? Can the rapid decline
in the rate in the United States and the equally rapid increase in Europe
be made consistent with the assumption that the constitutional factor is
the only vital one in the tuberculosis situation? As we have seen, the
very nature of the tuberculosis picture was markedly changed; in the
one case for the better, in the other, for the worse. In America, the
incidence of the disease by age was so completely changed during ten
years that one would hardly recognize the curve for age in 1922 as
representing the same disease in 1911. Changes in germ-plasm are
fixed by inheritance and cannot be developed in three or four, or even
ten years. They take generations for their fulfillment, and cannot,
therefore, be the cause for what occurred in the last few years.”

Certainly as applied to the United States, there is no evidence that
the changes that have occurred in the last decades have come about
through any improvement in the racial constitution of the people. The
eugenists have not lost an opportunity to say that in their Opinion no
improvement has occurred and, if anything, there has been deteriora-
tion. They have pointed to the decline in the birth rate of the most
favored classes, to the extensive immigration into the country of large
numbers of less favored people and to the other items that show that
the inherent capacity of the population may not have improved, It
would seem, therefore, that if the tuberculosis death rate has declined

 
LOUIS I. DUBLIN, PH.D. 25

in the United States, it has not done so because of the improvement of
stock during the period under question, but rather in spite of it.

On the other hand, the facts in both parts of the world are not at all
inconsistent with the assumption that we are concerned with changes
in the environment of the individuals whom we are considering. In
America, we see clearly evidences of remarkable improvement in the
status of the great mass of the people; the bettering of the conditions
under which they must work; the shortening of their hours of labor and
the increase of their earnings. From every angle, there is good evi-
dence that the population of America is better off. Never before in
the’ history of the country has so favorable a change come over the envi-
_ronment of the people as in the years subsequent to the great war.
Those who are engaged in the anti-tuberculosis programme point to the
enormous increase in the effectiveness of their organization, in the
multiplication of their facilities for the care of the tuberculous, to the
widespread campaign of education which has taken hold of the imagina-
tion of the people, affecting not only the school children but the whole
of the population.

The losses sustained in the tuberculosis movement abroad are just
as clearly related to the marked retrogression in the well-being of the
people. There were no fundamental changes in the germ-plasm of the
civilian population of Europe, but rather in the number and character
of the hardships to which they were exposed. The lack of food, of
clothing and of housing; the many worries and the disregard of hygiene,
which could scarcely be avoided, went hand in hand with the mounting
death rates from tuberculosis. The changes which occurred in Europe
on so large a scale and which were so sharply defined show that there
can be no mistake as to the relationship of environment to tuberculosis.
The facts, such as they are, are as conclusive as the facts of any labora-
tory experiment. It is on such grounds that those who consider the
environmental factor as dominant, rest their case.

May we not, therefore, conclude from this first section of our disctts-
sion that the very nature of the disease as expressed in its differential
incidence in the various groups of the population and in its capacity to
change is more consistent with the first rather than with the second of
the two explanations? It seems to me very clear that taking all of the
facts together, we are led into fewer difficulties by this course. The
second explanation, which assumes a differential racial constitution and
inheritance corresponding to the differences in the death rates, requires
in its turn still further explanation. The evidence is good that the factor
of immunity and racial constitution must be considered. But, there
has not been sufficient change in this regard to account for the reduction
in the death rate. Possibly, further research will add to the importance
of this factor by identifying certain types of constitution which go with
the greater or lesser ability to resist the development of tuberculosis.

 
26 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

But, this must always remain a minor item in the tuberculosis campaign
as it-is organized in the United States and in other civilized countries.
In the last analysis, it is the kind of environment we live in that deter-
mines the high or low rate which prevails.

III. DIRECT RESULTS OF THE WORK BY THE
TUBERCULOSIS AGENCIES

Fortunately, there is at our disposal another and a more direct mode
of approach which shows very clearly how effective are environmental
influences in the control of tuberculosis. We shall from this point on,
concern ourselves with an attempt to evaluate some of the major activi-
ties which have been developed in conjunction with the tuberculosis pro-
gramme to see if we can measure how much of the actual decline in
the death rate can be directly traced to them.

One of the first steps in the tuberculosis campaign has been to dis-
cover the early cases of tuberculosis and to provide care for them. For
thirty years, the sanatorium movement has developed rapidly and, today,
in the United States, there are available close to seventy thousand beds
for the care of the tuberculous. The theory behind this development
has been that those who receive such care have their disease more or less
arrested and their lives lengthened. We have been very negligent in
not attempting heretofore to evaluate this phase of the tuberculosis
movement, for much of the necessary evidence is at hand.

The end results of sanatorium care, quite irrespective of the location
of the institutions, are strikingly similar. Incipient cases give the best
promise, although the sanatoria cannot quite wipe out the effects of the
disease in even such cases. But, the records of the sanatoria of the
country show clearly that the after-mortality among the graduates is
from two to three times the normal for age. Those who have been
admitted in a moderately advanced stage of the disease have a subse-
quent mortality from eight to ten times the normal for age, and those
who have been admitted as “far advanced” cases show a mortality from
thirty to forty times the normal for age. These results are not limited
to one sanatorium alone but are typical of sanatoria in general. Patients
treated at Trudeau, at Mt. McGregor, in the King Edward VII Sana-
torium, do a little better than we have assttmed.- We have minimized
the gains to make them more representative of average sanatorium
conditions.

In contrast, the tuberculous, as a whole, have a mortality approximately
14 to 15 times the normal for age. This is indicated by the fact that
the fatality rate among the tuberculous is approximately ten per cent., or
100 per 1,000 per year, whereas, the mortality rate of the general popula-
tion at corresponding ages is approximately seven per 1,000. An estimate

 
LOUIS I. DUBLIN, PH.D. 27

of fifteen times the normal mortality for the tuberculous in all stages
is reasonable. It follows, therefore, that the effect of sanatorium care
consists in converting groups of individuals who, if left to their own
devices, might be expected to die at a rate of fifteen times the normal
into groups who die at a rate of from two to three times the normal
as do the incipient or from eight to ten times the normal as do the
moderately advanced cases. The far advanced cases probably receive
benefits as well, but their mortality rate is well above the average of
the tuberculous, and there is no satisfactory evidence as to the saving
actually effected. But, even as to them, there are other community
advantages which justify their care in sanatoria.

Let us see then what the effect of sanatorium care is on masses of
tuberculous cases. The best estimates that I can find indicate that
about 40 per cent. of the beds are available to early and incipient cases,
about as many more to the moderately advanced cases, and the
remainder, or 20 per cent., to far advanced cases. In a typical thousand
cases in sanatoria, there would then be 400 incipients, 400 moderately
advanced and 200 far advanced. As the result of the sanatorium care
on the above basis, there should be annually, subsequent to discharge, a
' total of about 90 deaths per thousand. In the community at large,
the number of deaths in a typical thousand of the tuberculous popula-
tion would be 100. There is, therefore, a net saving of 10 deaths per
thousand per year on the most conservative basis that we can use.
This is equivalent to a saving of ten deaths out of every 100 that would
otherwise occur, or 10 per cent. in the total tuberculosis mortality.
The importance of this saving depends, of course, on the total numbers
of persons who receive sanatorium care. At the present time, there
are approximately 70,000 beds caring for well in excess of 110,000 pa-
tients each year. There is, therefore, a saving of at least eleven hundred
lives a year as the result of the return to the community of the patients
of the preceding year. The number is not quite so large for past years
since the movement for providing sanatorium beds has been a rapidly
growing one. In 1904, there were 10,000 such beds; in 1910, these had
increased to 26,000 and, in 1922, as we have said, the number was about
70,000. These beds have an average turnover every six months, but
are not always fully occupied throughout the year. The maximum
capacity may need to be discounted by perhaps as much as 20 per cent.
On this basis, I estimate that not less than 800,000 persons have passed
through these sanatoria during the last decade, of whom close to six
hundred thousand are still alive and showing the benefits of reduced
mortality in their respective communities. At a minimum, therefore,
there are 6,000 less deaths per year from tuberculosis in this group than
would have occurred if sanatorium beds had not been available. There
is also a considerable number, not easily estimated, who received sana-
torium care in prior years, and who are still alive. The saving which
has occurred among them will increase the total to well in excess of the

 
28 CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

‘6,000 lives annually which we have ascribed to the effects of sanatorium
care. In fairness, however, such gains as we have noted should be
credited to the whole tuberculosis programme of which the sanatoria
are only a part. Without the clinics and their expert medical and nurs-
ing facilities, the auxiliaries and the social workers, many of the patients
would never have been discovered in the early stages of the disease nor
admitted to sanatoria, nor kept there until the treatment was completed.

There are, in addition, a large number of patients who receive excel-
lent care at the hands of private physicians, a large number of whom are
expert in the treatment of the tuberculous. At Saranac Lake and other
centers of the country, large colonies of the tuberculous have gathered
where they enjoy much the same type of supervision, direction and care
-as do those in the best sanatoria. It is, unfortunately, impossible to
estimate their number. But that it is large and that the results obtained
are in many ways comparable with those of the best sanatoria, there is
little question. It is regrettable that no estimates can be made of the
saving in lives accomplished through this medium. The number must
be large, however, and would add materially to the number already
credited to the effects of sanatorium care.

It is not my purpose in this address, even if it were possible, to ex-
haust all the major activities of the tuberculosis movement and to evalu-
ate the life saving achievement of each one of them. My purpose has
been rather to show how a typical and important agency has actually
resulted in a measurable amount of life conservation. That should serve
as an indication of what may be accomplished by the others, although
it will always be impossible, I suppose, to determine how much good
results from such work. Important as was the first or logical side of
our argument, this brief contribution on the direct results is even more
important. Together, the evidence should be irresistible that the recent
decline in the tuberculosis rate can be largely credited to the agencies
which have been put into operation, directly or otherwise, to control
tuberculosis.

You will notice that Iam careful not to ascribe the entire gain to the
tuberculosis movement. It is entirely conceivable that more has been
accomplished through the increase in real wages of the working classes
of the country, through the improved working condition in the factories,
and the improved wellbeing of the great mass of the workers, than
from all of the direct activities of the movement itself, such as, sana-
torium care, the service of physicians, etc. But, it is to the great credit
of the tuberculosis campaign that so much of the enlightenment that
now prevails in the relationship between employers and employees has
resulted from the intelligent stimulation by health and social workers
who have been interested in the control of tuberculosis. The campaign
of education has not been waged for naught. Any one who is familiar
with what has been accomplished in this country in the field of health

 
LOUIS I. DUBLIN, PH.D. - 29

education cannot fail to be impressed with the value of the work. The
tuberculosis movement, be it either through its direct or its indirect
influences, has made the body of American men, women and children
more resistant to the development of infection, keener to know the state
of their health, more intelligent as to their needs when disease has
developed, and more likely to obtain proper and sufficient care. The tu-
berculosis movement, therefore, stands clearly and outstandingly as a
major force in what has been accomplished.

IV. THE OUTLOOK FOR THE FUTURE

No one can possibly be familiar with the history of public health in
_the last twenty years and be other than optimistic as to the future of
the tuberculosis campaign. The experience through which we have
passed has clearly demonstrated that the campaign has been well con-
ceived and that the individual activities have been, on the whole, well
conducted. The effort has justified itself and is worthy of further ex-
tension. Much is still to be desired in making approved facilities avail-
able to the great mass of the American population and, even when avail-
able, so to coordinate them that the most effective results will be
obtained. You will remember that with reference to the effectiveness
of sanatoria, everything depended upon their ability to serve the incip-
ient cases first. It was because they succeeded in obtaining 4o per cent.
of their cases in the incipient stage and the rest moderately advanced and
far advanced, that a saving in mortality of 10 per cent., could be accom-
plished. If the sanatoria in the future could succeed, through the codper-
ation of the diagnostic and the social service agencies, to bring incipient
cases instead of advanced and far advanced cases to their service, the
mortality saving would be materially increased. Even if sanatorium
care itself were not made more effective, a change of the present propor-
tions to 60 per cent. incipient, and 20 per cent. moderately advanced, and
20 per cent. far advanced, would increase the annual mortality saving
from IO per cent. to 22 per cent. per year. Coupled with this internal
change in the management of sanatoria, there must be a further devel-
opment of sanatorium and bed facilities over many large areas of the
country. There are still too many states with either no or an inade-
quate number of sanatorium beds available to the tuberculous. We may
look forward, I believe, to a rapid extension of such facilities in the
near future. |

What then, may we say, on the basis of the facts of the last twenty
years, is the probable future trend of the tuberculosis death rate, and
what may we expect to achieve by the year 1930? While our data are
in many ways reliable, there is, nevertheless, an element of uncertainty
in making forecasts of this kind. As you will remember, the changes
in the tuberculosis death rate in the last few years have been very
marked indeed and rather unexpected. If, to be conservative, we

 
CAUSES FOR THE RECENT DECLINE IN TUBERCULOSIS

Cuart 5

 

Prospective Death Rates fo" Tuberculosis-All Forms

y iY 1922 to 1930
Original Registration States end District of Columbia

DEATHRATE
PER 100,000

 

200
190

180
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20

 

1900

YEARS

 

 

 
ea

LOUIS I. DUBLIN, PH.D. , 31

assume that the trend line of the last twenty years will continue with-
out change up to and including 1930, we may expect on that basis a
death rate of 88 per 100,000 at the end of this decade. But, this rate
is obviously too high as indicated by the fact that the population had
a rate in 1922 already probably below 90 and that in 1923 the figure
will be still lower. If, on the other hand, we were inclined to be more
radical and were guided by the trend of the last five years, say from
1916 to 1921, the estimated rate in 1930 would be about 7 per 100,000.
We know very well, however, that marked declines such as have occurred
in the years 1919, 1920, and 1921 are not likely to continue in equal
measure for a long period. In fact, the years 1922 and the current year
have shown a tendency to ease off in the rate of decline. My best judg-
ment, is, therefore, without making an attempt at finality or to involve
myself in any hairsplitting mathematical speculation, to compromise on
the two estimates, that is, to assumé a figure midway between 7 and 88.
That gives a rate which, I believe, is much more probable than either,
namely, about 50 per 100,000 for the year 1930. That is, in fact, the
result which would follow if the tendencies of the last few years were
slowed up about one-half for the remainder of the decade. Chart 55
page 30, gives us an interesting picture of the two trends based upon the
long and the more recent period of years, and of the development of the
probable rate for 1930.

A tuberculosis rate of 50 per 100,000 will, I believe, be found to be not
far from the actual figure in 1930. Please remember that in New Zea-
land and in Australia, a death rate from tuberculosis of 50 has already
been attained. Three states of the United States in 1921 had rates
below 50; in fact, two were below 4o. It is for this reason that I am
encouraged to consider this estimate entirely reasonable. It may even be
lower provided an effort is made during the next years to apply the
lessons of our experience with this disease during the last twenty or
thirty years. It may be much lower also if some effective biological or
other new method is discovered for the treatment or prevention of tuber-
culosis. The tuberculosis movement must not rest on its laurels
nor be allowed to drift along easy ways. The disease is on the decline.
This is an opportune time to apply even greater energy along approved
lines, that there may be no diminishing but rather cumulative returns in
life saving.