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Studies in the epidemiology of phthisis
PUBL1C H E A L T t t .
1914.
STUDIES
IN T H E E P I D E M I O L O G Y OF PHTHISIS. e
By ALEXANDER S. M . D.P.H., Tuberculosis
MACGREGOR, Officer, Glasgow.
M.D.,
L recently, studies in the epidemiology of T I Lphthisis have mainly been based on analyses of mortality statistics. The inclusion of consumption among the notifiable diseases has, however, had the effect "of enlarging the field of study, and it has become the custom to follow the receipt of notifications by an elaborate series of inquiries. The voluminous information in course of collection and analysis is being regarded with a measure of expectancy as having a bearing on the solution of administrative and scientific questions of local or national importance. Compulsory notification has been in operation in Glasgow since January, I9iO , and it was my intention to utilise the information collected since then for a preliminary study. The difficulties, however, surrounding inquiries which have for their object a general survey based on notifications have been so considerable that I propose to devote the main part of this paper to their discussion. These difficulties are obvious enough, but highly important. Briefly, they are both clinical and administrative, comprising under the former, errors in diagnosis, absence of uniformity in clinical standards, and varying significance of the notification; under the latter, imperfect organisation for getting into immediate touch with notified cases, and the disconcerting effect of migration. Variatiol~ in Clinical Standards : ~ I n the first place, clinical standards appear to vary from place to place, and at different age periods of life. Increase in facilities for early detection account for considerable variation in the frequency of notifiable tuberculosis of the lungs in different localities and even" in successive years in the same locality. Dr. Robertson, in his Annual Report for Birmingham for the year i912 , contrasts several large towns in respect of the proportion of notifications to every ioo deaths from consumption during the y e a r - - a convenient method of expressing, for purposes of comparison, the prevalence of notified pulmonary tuberculosis. Part of the table is here transcribed (see Table I). The figures in the last colunm show considerable discrepancies. In the case of Birmingham the ratio of cases to deaths *Read before a meeting of the Society of Medical Officers of Itealth ou 13th Marchj 191.4.
2~;9
exceeds that of most of the other towns, being twice that for Manchester, while the figure for Portsmouth is highest of all. T A B L E I.* Pr@ortiou of Notifications to IOO Deaths from Phthisis for several towm--year 1912. TowlL
D,R. per r,ooo,
Birmingham Liverpool
il
..
Manchester t3ra:lford
- • '~
Sheffield
Proportion of Cases to ioo Deaths.
4,394
404
I'49
3,690
329
"53
2,396
216
921
253
I,~67
475
~
..
Portsmouth
Total Notifications.
i'i 3 ..
98o
I73
Edinburgh..
i'26
1,255
309
Glasgow
i'32
2,330
2- 5
.,
This table reveals differences in frequency worth enquiring into', Comparing Birmingham (year 1912) with Glasgow (year 191o ) the first year of compulsory notification in both cities, and splitting the ratio of cases to deaths into several age groups we obtain the following result : T A B L E II. Birmingham and Glasgow--Comt~arisou of Cases Notified bet IOO Deaths for eac,h age gro@. I I -~ --] -~i -zo! -i 5 -2o-2 , 5 - 35 - 45 -55 -6565~~, ~ .z, Birmingham..
Glasgow
93 1,75o 1,18o494 591 178324303 209 172 t o4
. . 2071 544] 423 276,333 334]3 `32 3°9 23 ~5 229 ]327
It will be o b s e r v e d that in the case of Birmingham the ratios of cases to deaths are in excess of those for Glasgow at the age periods from 5 to 35, and that the discrepancy is greatest at the school age period. Between the ages of 5 and 15 the ratio for the former city is about three times that for the latter; contrasting similarly the results for the second year of notification in either city (Birmingham I9I 3 and Glasgow I9II), the ratio for Birmingham becomes 2,448 or 7 times that for Glasgow. In Diagram I. the contrast is between Birrningham for the years I912-I3, and Glasgow for the years i91o-I912 inclusive. Diagrams II. and III. show a greater similarity in result throughout the various age groups as between *These ligures are, of course, only compmable for those towns wilere I912 was the first year of notification since the cases registered during the first year will be in eXCess of those which come to light in succeeding years.
270
MAY,
PUBLIC HEALTH.
relatives of consumptive patients at the Royal Victoria Dispensary. There is a slight increase in the ratios at the higher ages, but generally they remain much the same as in Glasgow and less than in Birmingham.
Birmingham and Portsmouth, and again b~tween Glasgow and Sheffield. As an example of variation within the same city the case of Edinburgh may be noticed (Diagram IV.). Here the proportion of cases Z,~06 L3"00
I|
It
II
Z.200
?.tO0
F
t t t I I I |
Z t qoo
I
1,800
I I
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DIAGRAM I.
to deaths rose from 196 in 191o to 268 in 1911 , by far the greatest increase being at the period under 15 years of age when the ratio increased from 448 to 1,221, as the result of a more critical and extended examination of the
In the case of Portsmouth again, the proportion of cases to deaths for the several age periods is substantially the same as in Birmingham during the year 1912, while in the case of Sheffield in t912 the ratios are l o w e r
1914L.
PUBLIC
271
HEA LTH.
tuberculosis dispensaries-whose aim is to engage in an aggressive search for tuberculosis among the population of their area. It is thus apparent that medical practice varies markedly in the notification of pulmonary tuberculosis at all periods of life, particularly at school age. These variations in the interpreta-
throughout than in Glasgow with the exception of age 5-15 where the figure is almost double. In the medical report of the London County Council for 1912, Dr. Hamer specially refers to the high frequency of pulmonary tuberculosis at ages 5-15 in the returns from several of the metropolitan boroughs. The proportion which
ooo qoo I,iO0
,'too I,t oo {500 i S,O0
13120 /,ZOO
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765
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DIAGRAM II. notifications referring to children of school age bear to the total is variously given as follows :-Woolwich, 33"7 per cent. ; Paddington, 29"4 per cent.; St. Marylebone, 28"1 per cent.; Kensington, 18"3 per cent.; Battersea, 17"5 per cent.; Wandsworth, lO"4 per cent. ; Lambeth, 8'2 per cent. ; Chelsea, 8"3 per cent. ; these disproportions are directly attributable to the existence of special agencies--
tion of what precise clinical signs and symptoms constitute notifiable tuberculosis probably depend to a large extent upon the clinical acumen or even idiosyncrasy of those whose work brings them much into contact with tuberculosis. Where standards differ so markedly, the effect is to vitiate for comparative purposes the results of statistical inquiries carried out by medical officers of health on receipt of
MAY,
PUBLIC H E A L T H .
272
notifications. If any practical use is to be made of the data collected by such inquiries (which are often very elaborate), attention must be given to the need for clinical classification and standardisation. This, of course, is the function of the medical officers of a tuberculosis department who should make it their
also, no doubt, affects considerably the number of doubtful or suspected cases notified among contacts and others. For instance, the practice at the six Glasgow municipal tuberculosis dispensaries, is to adopt a conservative attitude towards notification. The health of suspected cases is watched over, adverse conditions of
~000
Iqoo 1,~'00
; oo t,300 I I~0 t J60
1~00 HO0
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DIAGRAM I I t .
business to get into immediate touch with as many notifie'd cases as possible. In this way a more accurate picture of the distribution, etc., of tuberculosis in the area would be obtainable and a signal service rendered to the study of its epidemiology. The diagnosis of pulmonary tuberculosis is admittedly difficult, especially in children. Not only do clinical standards differ but custom
environment remedied, and they are treated for any signs or symptoms, e.¢, catarrhal conditions, anaemia, etc., likely to aid the entrance or development of infection, the medical officer being responsible for treatment, classification and administration generally. As they are already under the observation of the public health dePartment, uncertainties of diagnosis are not regarded as sufficient ground for formal
PUBLIC HEALTH.
1914.
notification. Tuberculin is administered at the discretion ot the medical officer. The SubsequeJ,t History of Patients Notified in 191o "up to the end of 1913. It has been our experience in Glasgow--as, doubtless, elsev~here--that many notifications
273
tuberculosis of the lung came into force in Glasgow in January, I9IO; the total notifications during that year may be assumed to have included practically all the then known cases of phthisis in the city. This inquiry, therefore, resolves itself into a prospective
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,qoo
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........
1300
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are of doubtful validity, and that consequently statistics based on the inquiries which follow are subject to considerable qualification. For the double purpose of testing the accuracy of the notifications and of getting into touch with practical issues, I have endeavoured to follow the cases notified during I9IO into the present year. Compulsory notification of
account of a consumptive population, as revealed by notification, for a period of between three and four years. Following the patients in five yearly age groups into the succeeding years, we obtain Table III. on page 274, which gives the subsequent history of phthisis patients notified" in I9IO up to January I 9 I 4, showing the
274
losses by death, migration, etc. It should be along with Table IV., which e x p r e s s e s the same data as percentages. In the first four columns are given the deaths in each year and the total deaths from 191o to 1913 inclusive at different .age periods. The tables show that 1,775 cases, out of a total of 3,425 notified during I91O, died during these four years, while 66 notified cases died of diseases certified other than. tuberculosis, making a total percentage mortality of nearly 54; that 209, or 6'1 per cent., left the city in the interval ; that 328, or 9"6 per cent., disappeared, and have not been traced; and that 492 , or 14"4 per cent., could not be traced to the addresses given in the notifications. The survivors are divided into two groups-those in institutions, 8% or 2"3 per cent., and those remaining at home, 475, or 13"9 per cent. The 492 cases comprising the " not founds" belong to a class which causes considerable embarrassment. It is composed chiefly of inmates of model lodging-houses. A large number of them were notified on slender evidence. None of these 492 cases have since come under notice by re-notification or by application for treatment or by death certificate. They remain, however, on the records as notified cases. The figures quoted above illustrate some of the difficulties encountered in keeping trace of notified cases, and of making a just estimate of the circumstances surrounding the incidence of phthisis. The operation of the Insurance Act, along with increasingly efficient organisation, will very largely" eliminate many of these sources of difficulty. I should like now to direct attention to those survivors who remain under observation. Patients of school age attract particular notice. Referring to the Table of Deaths (Table V.) it will be observed that of the fatal cases in this group all but a very small percentage died within one to two years after notification. It will also be noted (Table I V . ) t h a t the losses by death are less than those of any other group; that a larger proportion of children than of adults died from causes other than pulmonary tuberculosis, while the number of survivors among them is larger. This bears out what we know of the relatively short duration of fatal phthisis in children of this age group, and suggests, in addition, the existence of a very chronic or easily~arrested type of tuberculosis of the lung in• children. I propose to discuss these surviving casesin the light of a study of their present condition read
MAY,
PUBLIC H E A L T H . and
past
history
since
they
came
under
o b s e r v a t i o n in i 9 1 o . TABLE
III.
GLASGOW--ANALYSIS OF PHTHISIS N O T I F I E D I N 191o.
CASES
History subsequent to Notification u~ to Januao, , 1914 , showing Losses by Death, Migration, Etc. .
I Deaths certified
~,
l~,e -
I I
Phthisis.
I
..... 7 .
--50
,.
-I
IO
-I 5 -2o -25 -3 ° -'35 -4 o -45 -5 ° -55 -6o -65 65 +
I6 39 58 57 44 41 34 28 24 I2 11
I .
.
I 8 20 I7 II 18 ~4 15 9 II 3 5
56 61 56 36 i1 o6 7° 69
~ i
39 27 69
i
27 22 29 46 43 37 33 25
i~
24 19 II
63
45
58 6 6
82 ~43
772
32
TABLE
.
.
.
.
.
.
" I 3 3 4 4, 5 6 4
2 4
.
.
Jo 441 143 451 273 52! 411 44i 377 I ]58391 58 350 i 36 347 i 276 1 201 248 3 7 I42 5 7 12o
4/ 4/
i 801475!3425
IV.
Subsequent History up to January, 1914 , of Cases Notified in 191o, showing Percentage Losses by Death, Migration, Etc. "~ ~ '~ ~" ~1 ~ "
Ages.
o ~..~
-5 -Io -I 5 -20 -25 -30 -35 -4 o -45 -50 -55 -6o -65 65+
63 .6 35'0 42'7 5T 2 57"4 55'9 52.6 48'5 487 50'4 5 v2 48"7 52'5 56'9
All Ages
5i'8
~_Remainder.
~
o ~k)
~
o~
i
3"5 16'9 15'4 lO'6 112 1i. 4 9'5 9'4 7'2 8'7 7'7 7'7 4"2 3'9
;'i 3'5 5"5 7"5 lO, 3 I1"O 12'3 239 20"3 24"6 33 '1 30"8 26"5 ,
Vg 14"--4
1"2 I'2 2 I 1'8 1"o 0"8 2'6 2"3 32 3'6 4"4 2'i 4'2
22'3 35'0 30'7 16'5 I2" 7 11' 7 14'o 16'6 1o' 4 io-I i 8'1 I 4"9 5'8
2"3
I 13"9
3__2
The Survivors of School Age.--The total number of survivors who have remained underobservation since notification i n 191o is IOO. A large number of these children have been kept under observation during the whole period since 191o, and all but six have been medically examined. The conditions found may conveniently b e tabulated as follows : Children with catarrhal .conditions affecting one or both -bases which c l e a r e d u p after a longer or shorter interval . . . . . . .
14
PUBLIC H E A L TH.
1914.
Children with s i m i l a r conditions which have persisted or r e c u r r e d . . . . . . . . Children with general c a t a r r h w h i c h has not yielded to t r e a t m e n t or has recurred from t i m e to t i m e . . . . . . . . . . Children with general c a t a r r h which has yielded to t r e a t m e n t after a longer or shorter period Bronchietasis . . . . . . . . . . Children in w h o m no definite evidence of tuberculosis was f6und, who were suffering from coughs, a n d who a r e now well, and w i t h o u t p h y s i c a l signs . . . . . . . . . . Card iac . . . . . . . . . . . . Children with r e l a t i v e apical dulness . . . . Empyema . . . . . . . . . . . . Children with tubercle bacilli in the spit ..
i2
16 13 5
17 2 7 I
7 94
T A B L E V.
Ca~es Notified in 191o who have since died. Percentages of Total Deaths in each Age Group, occurring during each of the four years 19 IO- 1913. Ages,
I912,
98"2 8o'4
-5 --IO
~72"2
-~5 -20 -25 -3 ° "-35 -4o -45 -50 -55 -6o -65 -65 + Atl Ages
gTa
63"5 58"3 68'o 55"3 61"6 64'8 62'2
66" 7 66"7 69o ..
65i
.. 17"9 26"2 25.o 24'6 27'0 21"4 24"1 20'1 I 2o"1 ! 189 [ rt"6 ~ 19. 0 ~-----19°
I'8 I: 7 i'6 5.1 8' 5 8'I 5"3 10"6 14"2 io'8 7'~ 15"9 4"8 86
I9r3,
Totals,
100'O ..
2"6 3'4 6'6 5'3 IO'O
4"1 4'3 11'8 5,8 9'5 3'4 5'3
IOO'O I0O O IOO O IO0'O IOO'O 100 O IOO'O IOO O IO0'O I00 0
Ioo o ioo'o IOO'O I00"0
Many of these clinical conditions are the sequelze of measles, whooping cough, or pneumonia. For instance, in 24 cases t h e onset was dated from an attack of measles, in eight from an attack of whooping cough, in five from both measles and whooping cough, and in five from an attack of pneumonia, making a total of 41 . Eighteen of these children are not attending school. The chief physical signs exhibited were catarrhal conditions of the lungs, subacute or chronic, commonly confined to one or both bases, and often persistent, recurring, and intractable, taking months to clear up, or remaining stationary throughout the three or four years during which they were under observation. The numbers given above could be considerably increased by including (unnotified) children attending the dispensaries. Children with physical signs conforming to this description are common in Glasgow.
Survivors of Age.Group Fifteen and over.~ As in the case of the former group, we have
275
endeavoured to keep under observation as many of this group as possible for the purpose of a medical census. This class consists of 356 cases, and I am able to furnish particulars of 289 of them, I58 males and 13I females, who were still alive at the beginning of the year. Our medical survey concludes as follows : Patients r e g a r d e d as definitely tubercular . . . . . . P a t i e n t s i n w hom the evidence for notification h a d a p p a r e n t l y passed off at t he date of examination, a nd who ha ve r e m a i n e d well -.. ,. P a t i e n t s in w h o m the evidence w a s doubtful , . . . .. P a t i e n t s affected w i t h ot he r ailm e n t s - bronchitis, asthma, bronchietasis, c a rdi a c disease, etc . . . . . . . . .
196"
33
=_ 67.8 %
r
',t ~ 93 = 32 2% 6 1
54
It may be of interest to add that of the I96 cases regarded as definitely tubercular 38 per cent. were reported to be in advanced stages of the disease, several having so remained since the date of notification in 19Io. This completes the record of an effort to study the natural history of the notified cases in a large city by prospective methods. Imperfect and inconclusive as affording material for generalisation, it serves to indicate some of the difficulties, administrative and clinical, which surround statistical inquiries based on notification data. Contact Notifications.--It is regarded as an axiom in anti-tuberculosis work that the members of a family where a case of phthisis has occurred should be subjected to medical scrutiny for the detection of other or early cases among those in the same household. It is, therefore, important to consider to what extent our experience of the past four years suggests any close relationship between primary and secondary cases in members of the same household. Since 191o a special record has been kept of tile occurrence of phthisis in the immediate household contacts of cases already under notice, and the results have now been tabulated for the years 1911 , 1912, and 1913. These records are based upon the notifications sent in during these years, and are here given without any scrutiny of their accuracy or any attempt at clinical classification. The results are given in Table VI. The columns in Table VI. may be explained seriatim. The first contains the cases in each Sputum positive in r3o cases, C
27(~
MAY,
P U B L IC t t E A L TIt.
year, on the basis of notifications, no correction being m a d e for age distribution. The b r o a d indication from the analysis is t h a t during t h e past three 3,ears 411 notifications have been received in respect of m e m b e r s of the same household as 375 previously notified cases. A s s u m i n g t h a t the yearly a t t a c k - r a t e for the general p o p u l a t i o n applies equally to
y e a r notified from h o m e addresses, and the second the c o n t a c t p o p u l a t i o n in association with them. In t h e third column, headed " p r i m a r y cases," are given the cases in each y e a r in respect of w h o m s u b s e q u e n t cases were notified, e.g., 132 p a t i e n t s notified in 191o have been followed by 15o s e c o n d a r y cases during the three y e a r s 1 9 1 1 - I 3 - - 7 4 in 1911, 51 in
TABLE VI. G L A s G o w . - - P h t h i s i s . S e c o n d a r y Cases in S a m e H o u s e h o l d . T a b l e S h o w i n g I n c i d e n c e of Notified T u b e r c u l o s i s of the L u n g s in C o n t a c t C a s e s for each y e a r 1911-1913 . ] I
SECONDARY CASES. 1912. I913 .
i911. _ _ .
Contams.
_
_
. . . .
Primary Actual Ex. ] I Aotual ExCases., Cases CCa s ae s .a e Di__ff. s . p e Cases. c t e c pecteu t
TO'I'AL,~ f
Actnal 1Zx-Cases. I pected
Actual Cases.
Expected Cases.
Diff.
89
q 61
",'ear.
Cases.
i9to
2477 ~to363
132
74
3 I i + 43i
51
31
+ 20
19ti
I936
8079
i26
46
24
58
24
+3'
33
21 -~- 12
137
69 +68
1912
I947
8424
8I
47
25
+ 2:
4°
22[@ I8
87
47 + 4°
I913
I9o5
7535
36
37
19
+ 18
37
+ i8
135
89
46
411
187
375
+ 22
......
i2o
55
65
i56
TABLE
Diff
80
76
Diff
VII.
GLASGOW ( I 9 I I - I 3 ) - - P h t h i s i s . S e c o n d a r y Cases. T a b l e Showing E x c e s s of Actual over E x p e c t e d Cases according to size of house. Whole Population. Population.
Cases.
Cage Rate per i,ooo.
313,923
1,387
4'4
:0,64
86
2 apartments
I ~IO2,O23
3,428
3"I
:5,I~
3 apartments
480,249
999
2"I
4 apartments and up
382,647
546
1' 4
Size of House.
i apartment
Secondary Cases.
Contact Population. pulati
Actual Cases.
Rate Expected. per i,oao,
C a s e
Actual.
Ratio of Expected to Actual Difference. Cases,
8'I
47
86
+ 39
x to 1.83
216
4"8
14o
216
+ 76
I to J'54
5,45
7o
45
32
70
+ 38
i to 2"t 9
8,41
39
4"6
Iz
39
+ 27
I to 3"25
1912, and 25 in I 9 1 3 - - n o t i f i e d from a m o n g a c o n t a c t p o p u l a t i o n of lO,363 persons. Similarly for I91I the table indicates t h a t there were 8,079 persons in c o n t a c t with 1,936 notified cases, of w h o m I26 have been followed by I37 s e c o n d a r y cases in a11--~46 in I911 , 58 in 1912, and 33 in 1913 . T h e figures given u n d e r the h e a d i n g " e x p e c t e d c a s e s " are calculated by a s s u m i n g t h a t the a t t a c k - r a t e a m o n g the respective c o n t a c t p o p u l a t i o n s was the s a m e as a m o n g the population generally for each
the c o n t a c t populations, 224 of these cases m i g h t be r e g a r d e d a s " expected cases," leaving I87 to r e p r e s e n t the excess for the three years a m o n g the c o n t a c t s of notified patients. T h o s e persons who h a d been associated w i t h the notified cases of a n y particular y e a r from i 9 t o to 1913 have so far, in each of the succeeding y e a r s (with one exception), yielded m o r e cases in p r o p o r t i o n to their n u m b e r s t h a n has the general population. But the excess is not great, their n u m b e r s v a r y i n g f r o m a b o u t I per cent.
1914:.
PUBLIC
to a little over 2 per cent. of the t o t a l h o m e cases notified in the y e a r in which the c o n t a c t cases occurred. C o m p a r i n g the c o n t a c t w i t h the general p o p u l a t i o n s involved in the period studied, the c a s e - r a t e per I,ooo in the f o r m e r group is 5'2, as against 2"8 in the latter group. I t will be of interest to consider the b e h a v i o u r of the incidence-rates When the cases are grouped socially (Table V I I . ) . T h i s table is self-explanatory. It shows the u n i f o r m g r a d a tion of incidence a m o n g the whole p o p u l a t i o n in accordance with social condition as e x p r e s s e d by size of house. A m o n g the c o n t a c t p o p u l a tion there is a s h a r p g r a d a t i o n b e t w e e n t h e one and t w o - a p a r t m e n t groups, but for the o t h e r groups the incidence alters little. I n d e e d , t h e case-rates a m o n g the better class c o n t a c t s exceed those for t h e similar g r o u p s of t h e general population. T h e s e tables p e r m i t of only very t e n t a t i v e conclusions. T h e y express results b a s e d u p o n " notifications " as t h e y come to hand, a n d a r e subject to t h e errors and qualifications earlier discussed. For instance, v a r i a t i o n in t h e locus of inquiry would in all p r o b a b i l i t y c o m p l e t e l y alter t h e c o m plexion of the tables. T h e n u m b e r s are too small to allow of m u c h manipulation. T h e r e is disclosed, howeyer, the g e r m of an interesting study, t h e result of which would be m o r e conclusive if spread over a longer period of time. T h e s e r e m a r k s fall s h o r t of m y original intention. T h e y indicate, however, the kind of studies for which an a c c u r a t e knowledge of the general incidence of phthisis is desirable, and the special defects and difficulties likely to be e n c o u n t e r e d in an effort to utilise the d a t a of notification for epidemiological purposes. DISCUSSION. The PRESIDI;NT said he was sure that Dr. Macgregor's interesting facts would give rise to a good deal of comment,and the paper was open for discussion. Dr. W. G. WILLOUGHBY said he wished to thank Dr. Macgregor for his very interesting paper, wMch he hoped they would see in full in the journal, together with the tables, so that they would be able to study them at leisure. As to the number of primary notificatlons in proportion to deaths : in the town he represented, which was very small, lie found there were five notifications to. every death, i.c., the notifications were just under 2oo, and the deaths 4 ° . The question of the value of sanatorium treatment was .very important, and the facts disclosed by Dr. Macgregor showed that the notifications should be carefully followed up, and the statistics regularly tabulated. H e understood Dr. Macgregor to say that there were just as many of those notified living who
HEALTH.
277
had not received sanatorium treatment as those who had received such treatment. If so, he hoped that that would be brought out in the paper, so that they should have the full facts before them. Dr. VEITCn CLAI~I~said he had been particularly interested in the reference in the paper to the incidence of mortality from phthisis amongst children. T h e y were all interested in the provision of institutions for the treatment of tuberculosis. H e had been lately connected with the proposal for the establishment of open-air schools for children, and if Dr. Macgregor's figures were correct it was a very moot question whether they would be able to do much good by the open-air schools. H e bad been struck with the incidence of death and capacity for work in the two classes ofadutts mentioned by Dr. Macgregor ; those who had been treated in sanatoria, and those who had not. H e had been interested in a sanatorium run by charitable means in which an inquiry had been made in reference to all the cases of mortality amongst those who had received not less than three months' treatment. In ckses of a very mild lesion of the apex of the lung the results of tile inquiry were so excessively bad that they dared not publish them, they had 7 ° per cent. of deaths of all very early cases, tIis own opinion was that they must give those patients a much longer stay in the sanatoria than had been anticipated ; and he knew of cases where under long treatment they had recovered perfectly. T h e y must look for curative results not only to the institutional treatment, but to the after-care, which was quite as essential, if not more so. H e would be inclined to doubt the accuracy of the deductions from the red figures in the table on secondary cases, for they had no indication as to how closely they had been brought into contact with those suffering from tuberculosis, except that they were in the same family, l i e knew of a case of five deaths amongst the occupants of one clerk's room. So far as the intimacy of contact was concerned the figures could not be accepted as absolutely correct. Professor E. \V. H o p e said that one of the most useful features of Dr. Macgregor's paper was the methods of investigation into the problems of phthisis which he suggested, and which in the future could be applied much more fully than in the past. As greater and more abundant facilities were given to tuberculosis officers and their deputies, they would be abie to make their diagnosis with more exactitude, and that would sweep away the difficulties which Dr. Macgregor had had to encounter, l i e had been struck with the modesty of the deductions which Dr. Macgregor had made from his figures as to the results of sanatorium treatment, and he was disposed to agree with the doctor's observations. T h e y must not, however, lose sight of the fact that at least half of the value of sanatorium treatment was the C2
~o78
PUBLIC HEA LTH.
isolation of the patient, the removal of the source of the infection and of the individuals who had contributed so largely to swell the figures. H e had made a note of Dr. Macgregor's facts for home consumption and adoption, and he hoped that in future they would be able to get fuller information which would clear away the extraordinary anomalies as to the prevalence of phthisis in different cities. I t was regrettable, but true, that every new method in the treatment of phthisis had been put forward in terms of inflation and exalted expectation, and the result had been to discredit it in the eyes of laymen, town and county councils, bailies, aldermen, etc., who looked with rather an unfriendly eye at the measures which had been suggested. T h e r e was no doubt that the medical profession were open to the reproach that inflated claims f o r certain treatment of phthisis had been put forward which had led to disappointment. SIR SHIRLEY F. MURPHY said he wished to thank Dr. Macgregor for his paper, which had whetted his appetite for more information than he had yet placed at their disposal. Dr. Hope had spoken as to the value of sanatorium treatment as a means of segregation leading to reduction of exposure to infection, but he supposed that if all the patients had had six months segregation instead of three, better results in that direction would not have been obtained. H e would like to see the relation between the social condition of the patient and the incidence of disease on the contacts stated. I f they had the figures derived from the poorer classes in Glasgow they might expect to find that the secondary cases would be higher than indicated in Dr. Macgregor's tables. Dr. C&LDWELL SMITH said he wanted more information as to the patients who had recovered. H i s experience was that the number was exceptionally s m a l l - - o u t of 2,8oo only as m a n y as could be counted on his fingers had completely recovered. If they had go t a doctor in a school who had tuberculosis on the brain, then the number of children declared to be suffering from the early stages of phthisis was inflated; and if they got a large proportion of children notified, that would make a very great ratio of notifications to deaths. T h a t was a question which ought to be thoroughly thrashed out, and also as to what was tuberculosis in children, tn his own experience, out of 5o0 contacts examined, only 5 2 , or IO per cent., proved to be tuberculous. T h a t showed that the preventative aspect of tuberculosis was going to be a greater problem than had been thought. The whole of their efforts should be directed to the prevention of the disease in children, and if so then the death-rate would go down enormously. Dr. E. H . T. NASH dwelt on the importance of diagnosis, In some schools 12 per cent. of the
MAY,
deaths of children were put down to tuberculosis, and that was due to the fact that the doctor saw tuberculosis in every case of notified sickness. H e insisted where tuberculosis was diagnosed they should be sent as speedily as possible to a sanatorium. In his own district it took two months from notification before the patient got into a sanatorium ; whereas amongst the officials of the post office it was only a week. DR. ALFRED GREENWOOD suggested that the statement made by Dr. Macgregor, that the working capacity of patients suffering from phthisis was equal among those who had never been in a sanatorium and those who had undergone a six months' sanatorium treatment, should be qualified, because hitherto sanatoria for early cases in this country had rarely been filled with early cases of phthisis. Until, therefore, these sanatoria for early cases were filled with the class of case for which they were intended originally, it was dangerous to draw any conclusions. The PRESIDENT said that the first impression he obtained from the excellent paper read by Dr. Macgregor was that something more was wanted than a simple record of notified phthisis. There were m a n y reasons for suggestinff that the administrative treatment which followed notification required that the notification itself should be viewed from a different standpoint than the customary one adopted with regard to infectious disease generally. T h e clinical features of phthisis, and its occasional long drawn-out history, were themselves sufficient tO make such differential treatment necessary. Another impression was that phthisis at school ages fluctuated so violently when different towns were compared that it was necessary to ask the question whether the term always represented the same pathological condition. A third p~int which he thought Dr. Macgregor's enquiry had emphasized was the variation which occurred in the incidence of phthisis when the cases were grouped according to certain economic standards, as represented by housing. The differing death-rates of these groups had been known for some time, but Dr. Macgregor had been able to expand this by illustrating how widely the attack-rate among them varied. H e regarded Dr. Macgregor's endeavour to ascertain the attack-rate among the household contacts with phthisis, as compared with other " n o n - c o n t a c t " members of the same economic grouping, was breaking distinctly new ground, and was likely ultimately to have a considerable bearing on the administrative problems to which the disease gave rise. H e was sure he expressed the feeling of the meeting when he conveyed to Dr. Macgregor their best thanks--first of all, for filling the gap which Dr. Robertson's unfortunate indisposition lind created, and in the second place for the most interesting paper which he had submitted.
1914.
STUDIES
IN T H E E P I D E M I O L O G Y OF PHTHISIS. e
By ALEXANDER S. M . D.P.H., Tuberculosis
MACGREGOR, Officer, Glasgow.
M.D.,
L recently, studies in the epidemiology of T I Lphthisis have mainly been based on analyses of mortality statistics. The inclusion of consumption among the notifiable diseases has, however, had the effect "of enlarging the field of study, and it has become the custom to follow the receipt of notifications by an elaborate series of inquiries. The voluminous information in course of collection and analysis is being regarded with a measure of expectancy as having a bearing on the solution of administrative and scientific questions of local or national importance. Compulsory notification has been in operation in Glasgow since January, I9iO , and it was my intention to utilise the information collected since then for a preliminary study. The difficulties, however, surrounding inquiries which have for their object a general survey based on notifications have been so considerable that I propose to devote the main part of this paper to their discussion. These difficulties are obvious enough, but highly important. Briefly, they are both clinical and administrative, comprising under the former, errors in diagnosis, absence of uniformity in clinical standards, and varying significance of the notification; under the latter, imperfect organisation for getting into immediate touch with notified cases, and the disconcerting effect of migration. Variatiol~ in Clinical Standards : ~ I n the first place, clinical standards appear to vary from place to place, and at different age periods of life. Increase in facilities for early detection account for considerable variation in the frequency of notifiable tuberculosis of the lungs in different localities and even" in successive years in the same locality. Dr. Robertson, in his Annual Report for Birmingham for the year i912 , contrasts several large towns in respect of the proportion of notifications to every ioo deaths from consumption during the y e a r - - a convenient method of expressing, for purposes of comparison, the prevalence of notified pulmonary tuberculosis. Part of the table is here transcribed (see Table I). The figures in the last colunm show considerable discrepancies. In the case of Birmingham the ratio of cases to deaths *Read before a meeting of the Society of Medical Officers of Itealth ou 13th Marchj 191.4.
2~;9
exceeds that of most of the other towns, being twice that for Manchester, while the figure for Portsmouth is highest of all. T A B L E I.* Pr@ortiou of Notifications to IOO Deaths from Phthisis for several towm--year 1912. TowlL
D,R. per r,ooo,
Birmingham Liverpool
il
..
Manchester t3ra:lford
- • '~
Sheffield
Proportion of Cases to ioo Deaths.
4,394
404
I'49
3,690
329
"53
2,396
216
921
253
I,~67
475
~
..
Portsmouth
Total Notifications.
i'i 3 ..
98o
I73
Edinburgh..
i'26
1,255
309
Glasgow
i'32
2,330
2- 5
.,
This table reveals differences in frequency worth enquiring into', Comparing Birmingham (year 1912) with Glasgow (year 191o ) the first year of compulsory notification in both cities, and splitting the ratio of cases to deaths into several age groups we obtain the following result : T A B L E II. Birmingham and Glasgow--Comt~arisou of Cases Notified bet IOO Deaths for eac,h age gro@. I I -~ --] -~i -zo! -i 5 -2o-2 , 5 - 35 - 45 -55 -6565~~, ~ .z, Birmingham..
Glasgow
93 1,75o 1,18o494 591 178324303 209 172 t o4
. . 2071 544] 423 276,333 334]3 `32 3°9 23 ~5 229 ]327
It will be o b s e r v e d that in the case of Birmingham the ratios of cases to deaths are in excess of those for Glasgow at the age periods from 5 to 35, and that the discrepancy is greatest at the school age period. Between the ages of 5 and 15 the ratio for the former city is about three times that for the latter; contrasting similarly the results for the second year of notification in either city (Birmingham I9I 3 and Glasgow I9II), the ratio for Birmingham becomes 2,448 or 7 times that for Glasgow. In Diagram I. the contrast is between Birrningham for the years I912-I3, and Glasgow for the years i91o-I912 inclusive. Diagrams II. and III. show a greater similarity in result throughout the various age groups as between *These ligures are, of course, only compmable for those towns wilere I912 was the first year of notification since the cases registered during the first year will be in eXCess of those which come to light in succeeding years.
270
MAY,
PUBLIC HEALTH.
relatives of consumptive patients at the Royal Victoria Dispensary. There is a slight increase in the ratios at the higher ages, but generally they remain much the same as in Glasgow and less than in Birmingham.
Birmingham and Portsmouth, and again b~tween Glasgow and Sheffield. As an example of variation within the same city the case of Edinburgh may be noticed (Diagram IV.). Here the proportion of cases Z,~06 L3"00
I|
It
II
Z.200
?.tO0
F
t t t I I I |
Z t qoo
I
1,800
I I
I, yo0
.I ) I
l,oo
t I t
t,500
~5oo I t I
U,{)O
t
t300
I
1200 I t I
t I00
t I I I
tOOO
qoo
I I I
gO0 ~00
I t
"-zt
500 .~00
. . . . . .
~fg
;,6
too a
.~
:to
45
-~o
.2,~
35
.~5
dJ
-b5
&~÷
DIAGRAM I.
to deaths rose from 196 in 191o to 268 in 1911 , by far the greatest increase being at the period under 15 years of age when the ratio increased from 448 to 1,221, as the result of a more critical and extended examination of the
In the case of Portsmouth again, the proportion of cases to deaths for the several age periods is substantially the same as in Birmingham during the year 1912, while in the case of Sheffield in t912 the ratios are l o w e r
1914L.
PUBLIC
271
HEA LTH.
tuberculosis dispensaries-whose aim is to engage in an aggressive search for tuberculosis among the population of their area. It is thus apparent that medical practice varies markedly in the notification of pulmonary tuberculosis at all periods of life, particularly at school age. These variations in the interpreta-
throughout than in Glasgow with the exception of age 5-15 where the figure is almost double. In the medical report of the London County Council for 1912, Dr. Hamer specially refers to the high frequency of pulmonary tuberculosis at ages 5-15 in the returns from several of the metropolitan boroughs. The proportion which
ooo qoo I,iO0
,'too I,t oo {500 i S,O0
13120 /,ZOO
t/oo I 6~0
goo ~'CO 76O
500 Z,O0 dog ZOO
I .
100
.
.
.
.
.
,
.
II}4 '0
5
-/5
-25
-~J
,yZ
765
D$
DIAGRAM II. notifications referring to children of school age bear to the total is variously given as follows :-Woolwich, 33"7 per cent. ; Paddington, 29"4 per cent.; St. Marylebone, 28"1 per cent.; Kensington, 18"3 per cent.; Battersea, 17"5 per cent.; Wandsworth, lO"4 per cent. ; Lambeth, 8'2 per cent. ; Chelsea, 8"3 per cent. ; these disproportions are directly attributable to the existence of special agencies--
tion of what precise clinical signs and symptoms constitute notifiable tuberculosis probably depend to a large extent upon the clinical acumen or even idiosyncrasy of those whose work brings them much into contact with tuberculosis. Where standards differ so markedly, the effect is to vitiate for comparative purposes the results of statistical inquiries carried out by medical officers of health on receipt of
MAY,
PUBLIC H E A L T H .
272
notifications. If any practical use is to be made of the data collected by such inquiries (which are often very elaborate), attention must be given to the need for clinical classification and standardisation. This, of course, is the function of the medical officers of a tuberculosis department who should make it their
also, no doubt, affects considerably the number of doubtful or suspected cases notified among contacts and others. For instance, the practice at the six Glasgow municipal tuberculosis dispensaries, is to adopt a conservative attitude towards notification. The health of suspected cases is watched over, adverse conditions of
~000
Iqoo 1,~'00
; oo t,300 I I~0 t J60
1~00 HO0
tooo
qoo gO0 1
yoo
I
\
I
~oo
\
i I
,580
', 5~/~
!
\
/
]~00
\
/
JOO
~\
\
200 I00
0
5
-/5
-LJ
25
45
6 : -~
DIAGRAM I I t .
business to get into immediate touch with as many notifie'd cases as possible. In this way a more accurate picture of the distribution, etc., of tuberculosis in the area would be obtainable and a signal service rendered to the study of its epidemiology. The diagnosis of pulmonary tuberculosis is admittedly difficult, especially in children. Not only do clinical standards differ but custom
environment remedied, and they are treated for any signs or symptoms, e.¢, catarrhal conditions, anaemia, etc., likely to aid the entrance or development of infection, the medical officer being responsible for treatment, classification and administration generally. As they are already under the observation of the public health dePartment, uncertainties of diagnosis are not regarded as sufficient ground for formal
PUBLIC HEALTH.
1914.
notification. Tuberculin is administered at the discretion ot the medical officer. The SubsequeJ,t History of Patients Notified in 191o "up to the end of 1913. It has been our experience in Glasgow--as, doubtless, elsev~here--that many notifications
273
tuberculosis of the lung came into force in Glasgow in January, I9IO; the total notifications during that year may be assumed to have included practically all the then known cases of phthisis in the city. This inquiry, therefore, resolves itself into a prospective
Z 000
,qoo
gO0 I (?I o
U oo
/
/ /
........
1300
l
I00
CCO
~. t
@0
!
I
g00 I
£00 500
l
,(fl
~UU
l
•
If~f
~,o
~
-
"-'-{i
lob
0
-15
-IO
<5
55
-65
-55
~0
]~) I AGF, AM I V .
are of doubtful validity, and that consequently statistics based on the inquiries which follow are subject to considerable qualification. For the double purpose of testing the accuracy of the notifications and of getting into touch with practical issues, I have endeavoured to follow the cases notified during I9IO into the present year. Compulsory notification of
account of a consumptive population, as revealed by notification, for a period of between three and four years. Following the patients in five yearly age groups into the succeeding years, we obtain Table III. on page 274, which gives the subsequent history of phthisis patients notified" in I9IO up to January I 9 I 4, showing the
274
losses by death, migration, etc. It should be along with Table IV., which e x p r e s s e s the same data as percentages. In the first four columns are given the deaths in each year and the total deaths from 191o to 1913 inclusive at different .age periods. The tables show that 1,775 cases, out of a total of 3,425 notified during I91O, died during these four years, while 66 notified cases died of diseases certified other than. tuberculosis, making a total percentage mortality of nearly 54; that 209, or 6'1 per cent., left the city in the interval ; that 328, or 9"6 per cent., disappeared, and have not been traced; and that 492 , or 14"4 per cent., could not be traced to the addresses given in the notifications. The survivors are divided into two groups-those in institutions, 8% or 2"3 per cent., and those remaining at home, 475, or 13"9 per cent. The 492 cases comprising the " not founds" belong to a class which causes considerable embarrassment. It is composed chiefly of inmates of model lodging-houses. A large number of them were notified on slender evidence. None of these 492 cases have since come under notice by re-notification or by application for treatment or by death certificate. They remain, however, on the records as notified cases. The figures quoted above illustrate some of the difficulties encountered in keeping trace of notified cases, and of making a just estimate of the circumstances surrounding the incidence of phthisis. The operation of the Insurance Act, along with increasingly efficient organisation, will very largely" eliminate many of these sources of difficulty. I should like now to direct attention to those survivors who remain under observation. Patients of school age attract particular notice. Referring to the Table of Deaths (Table V.) it will be observed that of the fatal cases in this group all but a very small percentage died within one to two years after notification. It will also be noted (Table I V . ) t h a t the losses by death are less than those of any other group; that a larger proportion of children than of adults died from causes other than pulmonary tuberculosis, while the number of survivors among them is larger. This bears out what we know of the relatively short duration of fatal phthisis in children of this age group, and suggests, in addition, the existence of a very chronic or easily~arrested type of tuberculosis of the lung in• children. I propose to discuss these surviving casesin the light of a study of their present condition read
MAY,
PUBLIC H E A L T H . and
past
history
since
they
came
under
o b s e r v a t i o n in i 9 1 o . TABLE
III.
GLASGOW--ANALYSIS OF PHTHISIS N O T I F I E D I N 191o.
CASES
History subsequent to Notification u~ to Januao, , 1914 , showing Losses by Death, Migration, Etc. .
I Deaths certified
~,
l~,e -
I I
Phthisis.
I
..... 7 .
--50
,.
-I
IO
-I 5 -2o -25 -3 ° -'35 -4 o -45 -5 ° -55 -6o -65 65 +
I6 39 58 57 44 41 34 28 24 I2 11
I .
.
I 8 20 I7 II 18 ~4 15 9 II 3 5
56 61 56 36 i1 o6 7° 69
~ i
39 27 69
i
27 22 29 46 43 37 33 25
i~
24 19 II
63
45
58 6 6
82 ~43
772
32
TABLE
.
.
.
.
.
.
" I 3 3 4 4, 5 6 4
2 4
.
.
Jo 441 143 451 273 52! 411 44i 377 I ]58391 58 350 i 36 347 i 276 1 201 248 3 7 I42 5 7 12o
4/ 4/
i 801475!3425
IV.
Subsequent History up to January, 1914 , of Cases Notified in 191o, showing Percentage Losses by Death, Migration, Etc. "~ ~ '~ ~" ~1 ~ "
Ages.
o ~..~
-5 -Io -I 5 -20 -25 -30 -35 -4 o -45 -50 -55 -6o -65 65+
63 .6 35'0 42'7 5T 2 57"4 55'9 52.6 48'5 487 50'4 5 v2 48"7 52'5 56'9
All Ages
5i'8
~_Remainder.
~
o ~k)
~
o~
i
3"5 16'9 15'4 lO'6 112 1i. 4 9'5 9'4 7'2 8'7 7'7 7'7 4"2 3'9
;'i 3'5 5"5 7"5 lO, 3 I1"O 12'3 239 20"3 24"6 33 '1 30"8 26"5 ,
Vg 14"--4
1"2 I'2 2 I 1'8 1"o 0"8 2'6 2"3 32 3'6 4"4 2'i 4'2
22'3 35'0 30'7 16'5 I2" 7 11' 7 14'o 16'6 1o' 4 io-I i 8'1 I 4"9 5'8
2"3
I 13"9
3__2
The Survivors of School Age.--The total number of survivors who have remained underobservation since notification i n 191o is IOO. A large number of these children have been kept under observation during the whole period since 191o, and all but six have been medically examined. The conditions found may conveniently b e tabulated as follows : Children with catarrhal .conditions affecting one or both -bases which c l e a r e d u p after a longer or shorter interval . . . . . . .
14
PUBLIC H E A L TH.
1914.
Children with s i m i l a r conditions which have persisted or r e c u r r e d . . . . . . . . Children with general c a t a r r h w h i c h has not yielded to t r e a t m e n t or has recurred from t i m e to t i m e . . . . . . . . . . Children with general c a t a r r h which has yielded to t r e a t m e n t after a longer or shorter period Bronchietasis . . . . . . . . . . Children in w h o m no definite evidence of tuberculosis was f6und, who were suffering from coughs, a n d who a r e now well, and w i t h o u t p h y s i c a l signs . . . . . . . . . . Card iac . . . . . . . . . . . . Children with r e l a t i v e apical dulness . . . . Empyema . . . . . . . . . . . . Children with tubercle bacilli in the spit ..
i2
16 13 5
17 2 7 I
7 94
T A B L E V.
Ca~es Notified in 191o who have since died. Percentages of Total Deaths in each Age Group, occurring during each of the four years 19 IO- 1913. Ages,
I912,
98"2 8o'4
-5 --IO
~72"2
-~5 -20 -25 -3 ° "-35 -4o -45 -50 -55 -6o -65 -65 + Atl Ages
gTa
63"5 58"3 68'o 55"3 61"6 64'8 62'2
66" 7 66"7 69o ..
65i
.. 17"9 26"2 25.o 24'6 27'0 21"4 24"1 20'1 I 2o"1 ! 189 [ rt"6 ~ 19. 0 ~-----19°
I'8 I: 7 i'6 5.1 8' 5 8'I 5"3 10"6 14"2 io'8 7'~ 15"9 4"8 86
I9r3,
Totals,
100'O ..
2"6 3'4 6'6 5'3 IO'O
4"1 4'3 11'8 5,8 9'5 3'4 5'3
IOO'O I0O O IOO O IO0'O IOO'O 100 O IOO'O IOO O IO0'O I00 0
Ioo o ioo'o IOO'O I00"0
Many of these clinical conditions are the sequelze of measles, whooping cough, or pneumonia. For instance, in 24 cases t h e onset was dated from an attack of measles, in eight from an attack of whooping cough, in five from both measles and whooping cough, and in five from an attack of pneumonia, making a total of 41 . Eighteen of these children are not attending school. The chief physical signs exhibited were catarrhal conditions of the lungs, subacute or chronic, commonly confined to one or both bases, and often persistent, recurring, and intractable, taking months to clear up, or remaining stationary throughout the three or four years during which they were under observation. The numbers given above could be considerably increased by including (unnotified) children attending the dispensaries. Children with physical signs conforming to this description are common in Glasgow.
Survivors of Age.Group Fifteen and over.~ As in the case of the former group, we have
275
endeavoured to keep under observation as many of this group as possible for the purpose of a medical census. This class consists of 356 cases, and I am able to furnish particulars of 289 of them, I58 males and 13I females, who were still alive at the beginning of the year. Our medical survey concludes as follows : Patients r e g a r d e d as definitely tubercular . . . . . . P a t i e n t s i n w hom the evidence for notification h a d a p p a r e n t l y passed off at t he date of examination, a nd who ha ve r e m a i n e d well -.. ,. P a t i e n t s in w h o m the evidence w a s doubtful , . . . .. P a t i e n t s affected w i t h ot he r ailm e n t s - bronchitis, asthma, bronchietasis, c a rdi a c disease, etc . . . . . . . . .
196"
33
=_ 67.8 %
r
',t ~ 93 = 32 2% 6 1
54
It may be of interest to add that of the I96 cases regarded as definitely tubercular 38 per cent. were reported to be in advanced stages of the disease, several having so remained since the date of notification in 19Io. This completes the record of an effort to study the natural history of the notified cases in a large city by prospective methods. Imperfect and inconclusive as affording material for generalisation, it serves to indicate some of the difficulties, administrative and clinical, which surround statistical inquiries based on notification data. Contact Notifications.--It is regarded as an axiom in anti-tuberculosis work that the members of a family where a case of phthisis has occurred should be subjected to medical scrutiny for the detection of other or early cases among those in the same household. It is, therefore, important to consider to what extent our experience of the past four years suggests any close relationship between primary and secondary cases in members of the same household. Since 191o a special record has been kept of tile occurrence of phthisis in the immediate household contacts of cases already under notice, and the results have now been tabulated for the years 1911 , 1912, and 1913. These records are based upon the notifications sent in during these years, and are here given without any scrutiny of their accuracy or any attempt at clinical classification. The results are given in Table VI. The columns in Table VI. may be explained seriatim. The first contains the cases in each Sputum positive in r3o cases, C
27(~
MAY,
P U B L IC t t E A L TIt.
year, on the basis of notifications, no correction being m a d e for age distribution. The b r o a d indication from the analysis is t h a t during t h e past three 3,ears 411 notifications have been received in respect of m e m b e r s of the same household as 375 previously notified cases. A s s u m i n g t h a t the yearly a t t a c k - r a t e for the general p o p u l a t i o n applies equally to
y e a r notified from h o m e addresses, and the second the c o n t a c t p o p u l a t i o n in association with them. In t h e third column, headed " p r i m a r y cases," are given the cases in each y e a r in respect of w h o m s u b s e q u e n t cases were notified, e.g., 132 p a t i e n t s notified in 191o have been followed by 15o s e c o n d a r y cases during the three y e a r s 1 9 1 1 - I 3 - - 7 4 in 1911, 51 in
TABLE VI. G L A s G o w . - - P h t h i s i s . S e c o n d a r y Cases in S a m e H o u s e h o l d . T a b l e S h o w i n g I n c i d e n c e of Notified T u b e r c u l o s i s of the L u n g s in C o n t a c t C a s e s for each y e a r 1911-1913 . ] I
SECONDARY CASES. 1912. I913 .
i911. _ _ .
Contams.
_
_
. . . .
Primary Actual Ex. ] I Aotual ExCases., Cases CCa s ae s .a e Di__ff. s . p e Cases. c t e c pecteu t
TO'I'AL,~ f
Actnal 1Zx-Cases. I pected
Actual Cases.
Expected Cases.
Diff.
89
q 61
",'ear.
Cases.
i9to
2477 ~to363
132
74
3 I i + 43i
51
31
+ 20
19ti
I936
8079
i26
46
24
58
24
+3'
33
21 -~- 12
137
69 +68
1912
I947
8424
8I
47
25
+ 2:
4°
22[@ I8
87
47 + 4°
I913
I9o5
7535
36
37
19
+ 18
37
+ i8
135
89
46
411
187
375
+ 22
......
i2o
55
65
i56
TABLE
Diff
80
76
Diff
VII.
GLASGOW ( I 9 I I - I 3 ) - - P h t h i s i s . S e c o n d a r y Cases. T a b l e Showing E x c e s s of Actual over E x p e c t e d Cases according to size of house. Whole Population. Population.
Cases.
Cage Rate per i,ooo.
313,923
1,387
4'4
:0,64
86
2 apartments
I ~IO2,O23
3,428
3"I
:5,I~
3 apartments
480,249
999
2"I
4 apartments and up
382,647
546
1' 4
Size of House.
i apartment
Secondary Cases.
Contact Population. pulati
Actual Cases.
Rate Expected. per i,oao,
C a s e
Actual.
Ratio of Expected to Actual Difference. Cases,
8'I
47
86
+ 39
x to 1.83
216
4"8
14o
216
+ 76
I to J'54
5,45
7o
45
32
70
+ 38
i to 2"t 9
8,41
39
4"6
Iz
39
+ 27
I to 3"25
1912, and 25 in I 9 1 3 - - n o t i f i e d from a m o n g a c o n t a c t p o p u l a t i o n of lO,363 persons. Similarly for I91I the table indicates t h a t there were 8,079 persons in c o n t a c t with 1,936 notified cases, of w h o m I26 have been followed by I37 s e c o n d a r y cases in a11--~46 in I911 , 58 in 1912, and 33 in 1913 . T h e figures given u n d e r the h e a d i n g " e x p e c t e d c a s e s " are calculated by a s s u m i n g t h a t the a t t a c k - r a t e a m o n g the respective c o n t a c t p o p u l a t i o n s was the s a m e as a m o n g the population generally for each
the c o n t a c t populations, 224 of these cases m i g h t be r e g a r d e d a s " expected cases," leaving I87 to r e p r e s e n t the excess for the three years a m o n g the c o n t a c t s of notified patients. T h o s e persons who h a d been associated w i t h the notified cases of a n y particular y e a r from i 9 t o to 1913 have so far, in each of the succeeding y e a r s (with one exception), yielded m o r e cases in p r o p o r t i o n to their n u m b e r s t h a n has the general population. But the excess is not great, their n u m b e r s v a r y i n g f r o m a b o u t I per cent.
1914:.
PUBLIC
to a little over 2 per cent. of the t o t a l h o m e cases notified in the y e a r in which the c o n t a c t cases occurred. C o m p a r i n g the c o n t a c t w i t h the general p o p u l a t i o n s involved in the period studied, the c a s e - r a t e per I,ooo in the f o r m e r group is 5'2, as against 2"8 in the latter group. I t will be of interest to consider the b e h a v i o u r of the incidence-rates When the cases are grouped socially (Table V I I . ) . T h i s table is self-explanatory. It shows the u n i f o r m g r a d a tion of incidence a m o n g the whole p o p u l a t i o n in accordance with social condition as e x p r e s s e d by size of house. A m o n g the c o n t a c t p o p u l a tion there is a s h a r p g r a d a t i o n b e t w e e n t h e one and t w o - a p a r t m e n t groups, but for the o t h e r groups the incidence alters little. I n d e e d , t h e case-rates a m o n g the better class c o n t a c t s exceed those for t h e similar g r o u p s of t h e general population. T h e s e tables p e r m i t of only very t e n t a t i v e conclusions. T h e y express results b a s e d u p o n " notifications " as t h e y come to hand, a n d a r e subject to t h e errors and qualifications earlier discussed. For instance, v a r i a t i o n in t h e locus of inquiry would in all p r o b a b i l i t y c o m p l e t e l y alter t h e c o m plexion of the tables. T h e n u m b e r s are too small to allow of m u c h manipulation. T h e r e is disclosed, howeyer, the g e r m of an interesting study, t h e result of which would be m o r e conclusive if spread over a longer period of time. T h e s e r e m a r k s fall s h o r t of m y original intention. T h e y indicate, however, the kind of studies for which an a c c u r a t e knowledge of the general incidence of phthisis is desirable, and the special defects and difficulties likely to be e n c o u n t e r e d in an effort to utilise the d a t a of notification for epidemiological purposes. DISCUSSION. The PRESIDI;NT said he was sure that Dr. Macgregor's interesting facts would give rise to a good deal of comment,and the paper was open for discussion. Dr. W. G. WILLOUGHBY said he wished to thank Dr. Macgregor for his very interesting paper, wMch he hoped they would see in full in the journal, together with the tables, so that they would be able to study them at leisure. As to the number of primary notificatlons in proportion to deaths : in the town he represented, which was very small, lie found there were five notifications to. every death, i.c., the notifications were just under 2oo, and the deaths 4 ° . The question of the value of sanatorium treatment was .very important, and the facts disclosed by Dr. Macgregor showed that the notifications should be carefully followed up, and the statistics regularly tabulated. H e understood Dr. Macgregor to say that there were just as many of those notified living who
HEALTH.
277
had not received sanatorium treatment as those who had received such treatment. If so, he hoped that that would be brought out in the paper, so that they should have the full facts before them. Dr. VEITCn CLAI~I~said he had been particularly interested in the reference in the paper to the incidence of mortality from phthisis amongst children. T h e y were all interested in the provision of institutions for the treatment of tuberculosis. H e had been lately connected with the proposal for the establishment of open-air schools for children, and if Dr. Macgregor's figures were correct it was a very moot question whether they would be able to do much good by the open-air schools. H e bad been struck with the incidence of death and capacity for work in the two classes ofadutts mentioned by Dr. Macgregor ; those who had been treated in sanatoria, and those who had not. H e had been interested in a sanatorium run by charitable means in which an inquiry had been made in reference to all the cases of mortality amongst those who had received not less than three months' treatment. In ckses of a very mild lesion of the apex of the lung the results of tile inquiry were so excessively bad that they dared not publish them, they had 7 ° per cent. of deaths of all very early cases, tIis own opinion was that they must give those patients a much longer stay in the sanatoria than had been anticipated ; and he knew of cases where under long treatment they had recovered perfectly. T h e y must look for curative results not only to the institutional treatment, but to the after-care, which was quite as essential, if not more so. H e would be inclined to doubt the accuracy of the deductions from the red figures in the table on secondary cases, for they had no indication as to how closely they had been brought into contact with those suffering from tuberculosis, except that they were in the same family, l i e knew of a case of five deaths amongst the occupants of one clerk's room. So far as the intimacy of contact was concerned the figures could not be accepted as absolutely correct. Professor E. \V. H o p e said that one of the most useful features of Dr. Macgregor's paper was the methods of investigation into the problems of phthisis which he suggested, and which in the future could be applied much more fully than in the past. As greater and more abundant facilities were given to tuberculosis officers and their deputies, they would be abie to make their diagnosis with more exactitude, and that would sweep away the difficulties which Dr. Macgregor had had to encounter, l i e had been struck with the modesty of the deductions which Dr. Macgregor had made from his figures as to the results of sanatorium treatment, and he was disposed to agree with the doctor's observations. T h e y must not, however, lose sight of the fact that at least half of the value of sanatorium treatment was the C2
~o78
PUBLIC HEA LTH.
isolation of the patient, the removal of the source of the infection and of the individuals who had contributed so largely to swell the figures. H e had made a note of Dr. Macgregor's facts for home consumption and adoption, and he hoped that in future they would be able to get fuller information which would clear away the extraordinary anomalies as to the prevalence of phthisis in different cities. I t was regrettable, but true, that every new method in the treatment of phthisis had been put forward in terms of inflation and exalted expectation, and the result had been to discredit it in the eyes of laymen, town and county councils, bailies, aldermen, etc., who looked with rather an unfriendly eye at the measures which had been suggested. T h e r e was no doubt that the medical profession were open to the reproach that inflated claims f o r certain treatment of phthisis had been put forward which had led to disappointment. SIR SHIRLEY F. MURPHY said he wished to thank Dr. Macgregor for his paper, which had whetted his appetite for more information than he had yet placed at their disposal. Dr. Hope had spoken as to the value of sanatorium treatment as a means of segregation leading to reduction of exposure to infection, but he supposed that if all the patients had had six months segregation instead of three, better results in that direction would not have been obtained. H e would like to see the relation between the social condition of the patient and the incidence of disease on the contacts stated. I f they had the figures derived from the poorer classes in Glasgow they might expect to find that the secondary cases would be higher than indicated in Dr. Macgregor's tables. Dr. C&LDWELL SMITH said he wanted more information as to the patients who had recovered. H i s experience was that the number was exceptionally s m a l l - - o u t of 2,8oo only as m a n y as could be counted on his fingers had completely recovered. If they had go t a doctor in a school who had tuberculosis on the brain, then the number of children declared to be suffering from the early stages of phthisis was inflated; and if they got a large proportion of children notified, that would make a very great ratio of notifications to deaths. T h a t was a question which ought to be thoroughly thrashed out, and also as to what was tuberculosis in children, tn his own experience, out of 5o0 contacts examined, only 5 2 , or IO per cent., proved to be tuberculous. T h a t showed that the preventative aspect of tuberculosis was going to be a greater problem than had been thought. The whole of their efforts should be directed to the prevention of the disease in children, and if so then the death-rate would go down enormously. Dr. E. H . T. NASH dwelt on the importance of diagnosis, In some schools 12 per cent. of the
MAY,
deaths of children were put down to tuberculosis, and that was due to the fact that the doctor saw tuberculosis in every case of notified sickness. H e insisted where tuberculosis was diagnosed they should be sent as speedily as possible to a sanatorium. In his own district it took two months from notification before the patient got into a sanatorium ; whereas amongst the officials of the post office it was only a week. DR. ALFRED GREENWOOD suggested that the statement made by Dr. Macgregor, that the working capacity of patients suffering from phthisis was equal among those who had never been in a sanatorium and those who had undergone a six months' sanatorium treatment, should be qualified, because hitherto sanatoria for early cases in this country had rarely been filled with early cases of phthisis. Until, therefore, these sanatoria for early cases were filled with the class of case for which they were intended originally, it was dangerous to draw any conclusions. The PRESIDENT said that the first impression he obtained from the excellent paper read by Dr. Macgregor was that something more was wanted than a simple record of notified phthisis. There were m a n y reasons for suggestinff that the administrative treatment which followed notification required that the notification itself should be viewed from a different standpoint than the customary one adopted with regard to infectious disease generally. T h e clinical features of phthisis, and its occasional long drawn-out history, were themselves sufficient tO make such differential treatment necessary. Another impression was that phthisis at school ages fluctuated so violently when different towns were compared that it was necessary to ask the question whether the term always represented the same pathological condition. A third p~int which he thought Dr. Macgregor's enquiry had emphasized was the variation which occurred in the incidence of phthisis when the cases were grouped according to certain economic standards, as represented by housing. The differing death-rates of these groups had been known for some time, but Dr. Macgregor had been able to expand this by illustrating how widely the attack-rate among them varied. H e regarded Dr. Macgregor's endeavour to ascertain the attack-rate among the household contacts with phthisis, as compared with other " n o n - c o n t a c t " members of the same economic grouping, was breaking distinctly new ground, and was likely ultimately to have a considerable bearing on the administrative problems to which the disease gave rise. H e was sure he expressed the feeling of the meeting when he conveyed to Dr. Macgregor their best thanks--first of all, for filling the gap which Dr. Robertson's unfortunate indisposition lind created, and in the second place for the most interesting paper which he had submitted.