Is Pneumonia Increasing

PROCEEDINGS OF

THE

NATIONAL ACADEMY OF SCIENCES Volume

Number 5

MAY 15, 1924

10

IS PNEUMONIA INCREASING? By EWALD TOMANEIC AND EDWIN B. WILSON' HARVARD SCHOOL OF PUBLIC HSALTH, BosToN

Read before the Academy April 30, 1924

It is probably impossible to answer the question: Is pneumonia increasing? The diagnosis is uncertain; an eminent authority writing to us states that whether a physician reports on a death certificate lobar pneumonia, bronchopneumonia, influenza or bronchitis must rest in many cases on his whim. But if we deal with large numbers it may be contended that the whimsy (chance?) fluctuations should average out and leave the mass statistics accurate-true if the fluctuations are really by chance and exempt from that form4tion and modification of mass habits which is observed in many organic fields. To throw some light on the situation a number of curves will be shown and discussed; the details of the numerical values must be reserved for publication when more space is available. SPECIFlC

smr

NMTE

iuu1

Pfleumo ia,ai

/AV-Am Sutalesfa.

furrebm Ama a rag tftt" itates.

.30

____ _____u 40 4 "Is --

-%.- W

IMA4

-~ ~

JL

,s,

,

,,,

/Wo st ~i I- Nisx FIGURE 2

,

\

AMO

4-

Figure 1 shows on arith-log paper the course of the mortality due to bronchopneumonia, to lobar and undefined pneumonia and to pneumonia

162

PROC. N. A. S.

STATISTICS: TOMA NEK A ND WILSON

forms in the U. S. registration area, 1900-1920 inclusive. Like almost pneumonia curves for the period including 1918 these show the peaks due to influenza, moderate for bronchopneumonia but very marked for lobar and undefined pneumonia and also for pneumonia all forms. Apart from these peaks the death rate from pneumonia other than bronchopneumonia is clearly declining, sharply for lobar and undefined pneumonia, but moderately for pneumonia all forms in which bronchopneumonia with its steady increase is included. The registration area was rapidly expanding from 1900-1920 from ten states with a population of 31 million to about three quarters of all our states and 87 millions of our population. Figure 2 shows the course of mortality when the statistics are confined to the ten original states. In these, pneumonia all forms is holding about constant (abstraction being made of the influenza year), bronchopneumonia is increasing rapidly, lobar and undefined pneumonia are declining slowly, bronchitis is dropping fast. The marked differences between the course of mortality in the registration area with its greatly widening limits and in the original ten states shows the necessity of holding the geographical limits fast if inferences are to be valid. In figures 3 and 4 are given the age specific mortality rates from respiratory diseases and pneumonia all forms in the ten original states. Thus not only are changes of geographical area disallowed but fluctuations in the age distribution of the population are held under control. Mortality all

all

A16 SPfCfilC NTHR4TE Ciwases fespoir6to, 4 S Cl CD llP T ow-~~~~~~~~~~~~~~~fo rea wial fgistAwtiee riomd 'a's"&nsI tke

P emwi.

States

r~~~~7-oe

, ,

4 500

k

~~~~~60-69

.1

20< ~~~~~~-AtX V_

-4

4-

MOX ,Soo

4 t

le

A 200 -oo N WC

30

1# 'lll 'lll

900

All Forms S&,,

/at&elO OVlReg,trfnat i,

19001920

1905

me

'lll

FIGURE 3

INS

'AS9/o

/Me

,=. s JO

_

,_

l-I

9w

twoA1-

FIGURE 4

from respiratory diseases is apparently slowly falling off in all age groups except for the indications that in the groups 10-19 and 20-39 which were

VoL. 10, 1924

163

STATISTICS: TOMANEK A ND WILSON

hit very hard by the influenza the post-influenza rate has not come back to its pre-influenza figure. Persons over 60 had a lower respiratory and pneumonia mortality in 1918 than in the previous year. The curves for pneumonia are on the whole practically horizontal and indicate no increase or decrease in the mortality from all forms of pneumonia. Figures 5 and 6 give a similar analysis for acute and for chronic bronchitis. For the former the mortality has been cut in two and for the A&eSPECi/rflEATH WATE Clujnc B&ohitis TenOr;l i tS tates

AWCSPtC/flCDtAH WAE fro," aAcute in&rchitis the Ten rign feij&stta 5tes Owil thehfSd 19-1b t

100

-

200

Xe

_

o.DIIIen te Ib,Xrie 19042

I2 Z

e05

Vw




A >

nGU0 FIGURE, 5

915

AM

19vo

IW5

FIGURE 6

Ns5

-So

latter somewhat better than cut in two in 21 years. For chronic bronchitis the decline is at about the same rate in all age groups. For acute bronchitis the situation is somewhat mixed, the rates of decline vary and there is even a slight increase in the most advanced ages. With bronchopneumonia theie is a marked increase at each age (fig. 7). Whether in reality these rates of increase or decrease are of biological or clinical importance, whether they may be due to some progressive change in the diseases, or whether they are due to shifting diagnosis, or how the rates of change should best be divided up and assessed in part to the one and in part to the other cause is very difficult to say. In 1910 the group lobar and undefined pneumonia was subdivided and

164

STATISTICS: TOMA NEK AND WILSON

PROC. N. A. S..

for 11 years we may trace separately the course of mortality due to lobar and undefined pneumonia as shown in figures 8 and 9. The two groups taken together (fig. 2) exhibited a practically constant mortality in this A¢&SPrCIfIC OEM1Mr Brwpneumania hw &ic/iini R.gisowtStatea lfo-9 0

-

FIGURE 7

period (exception being made of the influenza year 1918); but takren individually we see that undefined pneumonia which started in 1910 with a rate at least as high as lobar has declined with remarkable precipitancy to about one-eighth of its original value while lobar~pneumonia has as steadily climbed in 1920 to about double its mortality in 1910, the effect being particularly marked in thie large age group 20-39. TEN~ORIGINAL R18GISTRATION STAinS 1900-1920 DISEASE

MEAN RATE

iS. D.

TREND

DISTURDANCY

k

p

All respiratory 196. =5. 10% 11.4 6% -2.6~ .4 Pneumonia A.rP. 152.5 ~2. - .4** 3 6% 9.1 6% Pneumonia L. and U. 105.5 ~3.6 -2.1 .4 9.9 9% 14%o Bronchopneumonia 47. =12.3 +1.7=~.13 23%~ 3.2 7% Bronchitis 26.7 ~1.8 31% 3.4 9% -1.3~.1 * The column headed R gives the standard deviation of the residuals after the elimination of the trend, and that headed p gives the coefficient of disturbancy measured after the trend is out. In all calculations the excessive rates in 1918 have been discarded or adjusted. Considering the supposed considerable effect of the weather on the incidence of and morbidity from these diseases, the reduced coefficients of disturbancy p are perhaps surprisingly small.

VoL. 10, 1924

STATISTICS: TOMANEK AND WILSON

165

We have similar figures for each of the ten original states but shall pass them by. The numerical values for the means, standard deviations, trends, coefficients of disturbancy, etc., are also available. But here we shall offer these values only for the ten states continued. A6t1CIfCATHAT

AGf.W(CF/CDIATHPAT

(perim IDODGOCPop. HeAre ire f g" mista kAle/ o k & /0

(wOM

Ld;r Pmwuenia In Ik /OOti atinSxtes

"Ig

ta1io Pined

OurelnthceAwo! 0-

_0

----192

500 4. Jo#

-

1.

a

k i1.

4-

20

~

~

I

a k

I

1.

FIGURE 8

Ill I

1I1

I

FIGURE, 9

The general inference from this table which is based on a reasonably uniform population over a considerable period of time is that the mortality as reported for all respiratory diseases, for lobar and undefined pneumonia, and for bronchitis is decreasing with a statistically significant trend, whereas bronchopneumonia is increasing and pneumonia all forms is holding steady. Considering, however, the behavior of lobar and undefined pneumonia individually, the difficulties of diagnosis, the many diseases for which pneumonia is the term-iinal phase and others (particularly the heart group) which may complicate and terminate pneumonia, taking further into account the fact that the period 1900-1920 was one of rising prices with rising standards of living and that the economic situation may not always be so favorable, and remembering that the year 1918 (which has to be adjusted in a 21-year series but would have to be taken more fully into account in 50-year series) undoubtedly had a considerable excess of real pneumonia, all that we think it safe at present to infer is that pneumonia is neither increasing or decreasing, that the human organism

166

MATHEMATICS: G. A. MILLER

PROC. N. A. S.

is reasonably in equilibrium with its environment with respect to this disease. This paper is a brief account of a small part of a large statistical investigation in the epidemiological situation relative to pneumonia begun by Dr. Tomanek, Fellow of the International Health Board, under Dr. M. J. Rosenau and continued in association with me. A sudden call to the Health Section of the League of Nations forced Dr. Tomanek to leave to me the composition of this work which is so largely his. E. B. W.

PRIME POWER SUBSTITUTION GROUPS WHOSE CONJUGATE CYCLES ARE COMMUTATIVE G. A. MILLER DEPARTMUNT

OF

MATHMATICS, UNIVZRSITY

OF ILLINOIS

Communicated April 4, 1924

From the fact that the number of letters in every set of conjugate cycles of a substitution group is equal to the order of this group when each such cycle is counted for every substitution in which it appears it may be inferred that the further study of the properties of sets of conjugate cycles would be desirable.' One of the simplest cases presents itself when it is assumed that all the cycles in every set of conjugate. cycles are commutative. Even this case involves many difficulties which have not yet been overcome. If we assume that the group G is transitive and has an order of the form pm, p being a prime number, it is not difficult to prove that the subgroup G1 composed of all the substitutions of G which omit a given letter must always be cyclic. The proof of this theorem may be based upon an interesting property of the holomorph of the cyclic group of order pm, which may be stated as follows: The largest subgroup of the holomorph of the cyclic group H of order pm, when H is written as a regular substitution group, which satisfies the two conditions that it involves H and that its conjugate cycles are commutative is of order p3m/2 when m is even and greater than 2. When m is odd this order is p(3m-l)/2* If p is odd this theorem remains true when m = 2. In this case the subgroup of the group of isomorphismsn of H which enters into the subgroup in question is completely determined by its order, while when p = 2 it is determined by its order together with the fact that it transforms the operators of order 4 contained in H into themselves. By means of the theorem noted in the preceding paragraph it is not difficult to extend the result stated at the close of the first paragraph as follows: If G represents any transitive group whatever involving only commutative conjugate cycles the subgroup G1 composed of all its substitutions which