MORTALITY AND 31ORBIDITY &‘l%e)M HEART DISEASE CNDEX INDUSTRIAL A4ND GROUP 1KSIRAl‘alCE

WADE ~%T:XICIIT,* M.D. NEW YORK, N. Y.

EART disease and limitation of capacity for physical exertion are SO closely associated, and heart disease may be so aggravated by

physical exertion that it might quite naturally be assumed that the interrelations of heart disease and occupation would be reflected in high mortality rates in at least a considerable number of occupational groups. There is little evidence, however, that such excessive occupa- tional mort’ality exists.

This is a matter of particular interest when it is remembered that heart disease is foremost, among the causes of deat.11. In striking cou- trast stand pulmonary tuberculosis, pneumonia and accidents, all of \vhich display clearly the influence of occupation upon mortality rates.

Tuberculosis is the cause of grossly excessive mortality among such workers exposed to silicious dusts as hard rock miners, pottery mork- ers, stone cutters and grinders and amon, v such workers as waiters, cigar makers, laundry workers and printers (see Tables I and VI).

Pneumonia causes a still more marked excessive mortality among

iron foundry workers, cordage workers. metal polishers, miners and &eel workers.

Deaths from accident are more readily associated with occupation, and the very high death rates from accidental violence among electric linemen, railway workers, coal miners, structural iron workers, city firemen, roofers and others are, of course, extreme examples of the effect of occupation upon mortality.

There is undoubtedly some degree of association of social or eco- nomic status and mortality from heart disease. This is reflected in the morta.lity rat.es from this cause in the several classes of insured per- sons. The “ordinary” class is made up, b aenerally speaking, of the most

favored individuals ; the ” indus’trial ” class is made up largely of wage earners holding small policies, and the “intermediate” class falls between.

These observations are confirmed in the last repol~t of the Registrar General of England and Wales, 1923.-1923.

It is unfortunate that the statistical data relating to deaths among those covered by group insurance and by industrial insurance are not, at present, in such form as to permit of the recognition of mortaliQr rates by specific occupations.

*Assistant Medical Director, MetT’opolitan Life Insurance Company. Read at the Annual Meeting of the Amex’ican Heart Association. February 4. 1929.

448

TABL

E 1

OCCU

PATI

ONS

SHOW

ING

THE

HIGH

EST

PEBC

ENTA

GE

OP

DEAT

HS

BROM

SP

ECIF

IED

CAUS

ES

OF

DEAT

H LI

STED

AC

CORD

ING

TO

THEI

R ST

ANDA

RDIZ

ED

RATI

OS"

MO

RTAL

ITY

EXPE

RIEN

CE

OF

MET

ROPO

LITA

N LI

FE

INSU

RANC

E CO

MPA

NY

ON

WHI

TF,

MAL

E IN

DUST

RIAL

PO

LICYH

OLDE

RS

15

To

64

YEAR

S.

1922

-192

4

TUBE

RCUL

OSIS

O

F TH

E RE

SPIR

ATOR

Y SY

STEM

PN

EUM

ONIA

(A

LL

FORM

S)

OC

CU

PATI

ON

ST

ANDA

RDIZ

ED

OCCU

PATI

ON

STAN

DARD

IZE1

RA

TIO

RA

TIO

M

iners

(u

nder

grou

nd)

exclu

ding

co

al

Iron

foun

dry

work

ers

220.

0 m

iners

Potte

ry

work

ers

Ston

e cu

ttcTs

W

aite

rs

and

hote

l se

rvan

ts Cu

tlers

an

d gr

inde

rs

Ciga

r m

aker

s an

d to

bacc

o wo

rker

s La

andr

.~

work

ers

Com

posit

ors,

pr

inte

rs

and

pres

smen

Br

ass

foun

rlry

work

ers

Barb

ers

and

haird

ress

ers

Gla

ss

work

ers

Cler

ks,

book

keep

ers

and

offic

e as

sist

ants

Po

lishe

x (ir

on

and

stee

l pr

oduc

ts)

Shoe

fa

ctory

wo

rker

s Td

ors

and

othe

r clo

thin

g wo

rker

s Fu

rnitu

re

and

other

wo

odwo

rkers

Corda

ge

2nd

hclnp

I~

lill wo

rkers

Slau

ghter

xl1

13

pack

ing

hous

e wo

rkers

Shoe

mak

ers

(cobb

lers)

Bake

rs Al

l oc

eupa

.tion

s (e

mclu

diug

retire

d)

182.

7 17

6.5

144.

4 14

0.7

135.

8 13

5.2

134.

6 13

0.9

126.

5 12

5.9

123.

5 12

2.8

122.

2 11

8.5

118.

5 11

8.5

117,

9 11

7.9

116.

7 11

6.0

100.

0

Cord

age

and

hem

p m

ill

work

ers

Polis

hers

(ir

on

and

stee

l pr

oduc

ts)

Coal

m

iner

s (u

nder

grou

nd)

Iron

rind

stee

l m

ill

work

ers

Rubb

er

faet

ory

work

ers

IInck

ster

s rin

d pe

ddle

rs

Roof

ers

Long

shor

emen

an

d ste

vedo

res

Brick

, til

e an

d te

rra

cotta

wo

rker

s Bo

iler

mnk

crs

Gla

ss

work

ers

Labo

rers

Bl

acks

mith

s M

iners

(u

nder

grou

nd)

exclu

ding

co

al

min

ers

Ston

e cu

tters

St

reet

an

d se

wer

clean

ers

Mas

ons

and

brick

layer

s Ce

men

t an

d lim

e wo

rker

s O

il re

finer

y wo

rker

s Al

l oc

cupa

tions

(e

xclu

ding

re

tired

)

185.

0 18

3.8

150.

0 14

2.5

135.

0 13

2.5

131.

.3

130.

0 12

7.5

123.

8 12

0.0

120.

0 12

0.0

117.

5 11

7.5

115.

0 11

3.8

111.

3 11

0.0

100.

0

ACCI

DENT

AL

OR

UNDE

FINED

VI

OLEN

CE

OCCU

PATI

ON

STAN

DARD

IZED

RA

TIO

Elec

tric

linem

en

280.

8 Ra

ilway

en

ginc

men

an

d tra

inm

en

Coal

m

iner

s f u

nder

grou

nd)

Stru

ctur

al

iroil

work

ers

Fire

men

(c

ity

depa

rtmen

t) Ro

ofer

s Fi

sher

men

, oy

sterm

en,

sailo

rs

and

240.

0 22

7.5

218.

3 19

6.7

188.

3

mar

ine

work

ers

Mine

rs

(und

ergr

ound

) ex

cludi

ng

coal

m

iner

s Ra

ilway

tra

ck

and

yard

wo

rker

s Ch

emica

l an

d ex

plos

ives

facto

ry

work

ers

Cem

ent

and

lime

work

ers

Oil

refin

ery

work

ers

Brick

, til

e an

d te

rra

cotta

wo

rker

s Ch

auff

curs

W

atch

men

n:

:d

guar

ds

Raw

and

plan

ing

mill

wo

rker

s El

ectri

cian

s Pa

per

and

pulp

m

ill

work

ers

Long

shor

emen

an

d st

evcd

orcs

^. Ua

,rpen

ters

173.

3 17

0.0

160.

8 16

0.0

145.

8 14

5.0

143.

3 14

3.3

140.

8 13

7.5

128.

3 10

0.0

-- Al

l oc

cupa

tions

(e

xclu

ding

re

tired

) __

_- __

---.--

“T

he

Perce

ntage

of

de

aths

fro

m

each

sp

ecifi

ed

caus

e of

de

ath

in

the

the

age

perio

cl 15

to

64

ye

ars

amon

g al

l oc

cupa

tions

co

rnbinc

cl wa

s tak

en

as

100.

The

stan

&r&e

d PP

X’cnta

ge

for

each

ca

use

in

each

oc

cupa

tion

divid

ecl

by

the

eol'l‘e

spon

cling

perce

ntage

fo

r al

l oc

cupa

tions

co

mbin

ed

&es

the

stand

ardize

d ra

tio.

185.

0

184.

2 17

6.7

Group insurance is of relatively recent development. It is written at extraordinarily low rates because there are eliminated from the transactions all possible administrative and selective procedures. Pre- cise statements concerning the occupations of those insured are not required. In consequence the mortality which is experienced relates to industries and not to occupations. Physical examinations are not required so there is no physical selection of lives. Among those ex- posed to risk are individuals of varying ages, of either or both sexes, and to some extent, white or colored. It is evident that as group in- surance covers employees upon the payrolls of the respective insured

TILE II

DEATH R,ATES FROM OTHER DISEASES OF THE HEART METROPOLITAN LIPE IKSURANCE COMPANY, 1927

DEATHS PER 100,000 LIVES EXPOSED AT SPECIFIED AGES

AGE PERIOD ' ORDINARY CLASS IKTER,MEDIATE CLASS IXDUSTRIAL CLASS

(MALES) (MALES) (WHITE MALES)

20 to 24 years 11.2 12.6 20.5 25 to 34 years 10.9 18.3 38.3 35 to 44 years 27.9 52.1 90.0 45 to 54 years 118.6 195.8 284.0 55 to 64 years 343.9 427.8 738.4 65 to 74 years 1013.9 1171.3 1785.8 75 vears and over 3168.6 4166.7 4295.2

TABLE III

STANDARDIZED MORTALITY OF THE FIVE SOCIAL CLASSES am op ALL MALES. AGES 20 TO 65 YEARS

( (VALVULAR DINSEASE ' J OF THE HEART AND Cc OTHER HEART DISEASE I ’ REPORT OF THE REGISTRAR GENESAL FOR EKGLAND AND WALES, 1921-1923

K&J& disease of hea* f *~+&j[~[&/-$Z&J+ Other heart disease

*Social Class I-Upper and Middle. Social Class II-Intermediate. Social Class III-Skilled Workers. Social Class IV-Intermediate. Social Class V-Unskilled Workers.

groups, there is a tendency to eliminate from the exposure those indi- viduals whose incapacity because of heart disease is such as to prevent them from engaging in active work. A portion of those incapacitated

because of heart disease may, under group insurance, become eligible for total and perma,nent disability benefit,s. Such cases are charged as claim losses as of the dates of acceptance of the claims. Unf ortu-

nately, published statements of group claim experience do not offer a classification of such permanent and total disability claims, by cause. About 15 per cent are due to heart disease.

Accepting such data as are available in connection with the mor- bality from heart disease among the several million workers covered under group insurance, it is apparent that there exist relatively unim-

WRIGHT: MORTALITY AND MORBIDITY FROM HEART DISEASE 451

portant differences between the major classifications, such as ‘(rnin-

ix, ’ ’ ‘ ‘ iron, steel and other metals, ” ‘ ‘ transport,ation, ’ ’ ’ ‘ clerical, ’ ’ and “all others. ” Such differences as are observable in the several rates for each age are for the greater part to be explained by elements of selection incident to the demands of the respective industrial class&a- tions. The cardiac cripple will, for example, be almost automatically excluded from a heavy occupation. The operation of such tendencies has evidently been responsible for the levelling of cardiac mortality rates among the various occupational classes.

TABLE IV

DISEASES OF HEARTANT)'~IRCULATORY SYSTEM DEATHS PER 100,000 LIFE YEAXS

CENTRAL AGE

18 23 28 33 38 43 48 53 58 63 68 73 78 83 88

- MINING

Class I 14.0 23.8 34.6 46.8 45.2

112.9 188.3 316.5 505.7 765.6

1325.3 1293.1 2991.4 3333.3 5263.1

IRON, STEEL OTHER METALS

Class II

6.2 26.8

-

-

31.6 45.9 73.9

122.8 177.1 344.9 529.6 816.6

1600.0 2552.6 4354.8 6611.5

10000.0

TRANSPOR'TATION CLERICA

Class III

16.6 23.8 29.7 39.7 76.6

133.2 229.1 361.3 594.2

1020.2 1774.3 2556.6 4655.1 6666.6 9230.7

Class IV 19.8 13.8 28.4 32.8 53.2 95.9

184.7 356.2 546.6

1000.0 1551.1 2394.7 4114.3 5431.3 3571.4

1

.-

. -

!.LL OTHEKS

Class V 21.3 21.5 25.6 38.5 65.5

111.5 18.5.1 296.8 515.7 872.9

1386.2 1956.6 3273.7 6257.2 7260.6

At the present time group insurance data concerning morbidity from heart disease in relation to occupation are not to be had. It is possible, however, to present some general figures indicating the relative impor- tance of diseases of the circulatory system among t.he many causes of illness for which benefits are payable in time of sickness.

In a study of 6671 claims incurred under policies, paying benefits for approximately twenty-six weeks beginning on the eighth day of illness among white males, a life year exposure of 173,000 years, there were 323 or 4.8 per cent of the total number paid for losses due to various types of circulatory diseases, about 2 per 1,000. These claims involved the payment of 9 per cent of the total benefits paid for all causes and were of an average duration of 75.7 days which may be compared with an average duration of benefit of 41 days, and which is a greater dura- tion than that associated with any other group of disabilities.

Among white females under similar policy provisions, 34,000 life years, the diseases of the circulatory system accounted for 32 claims out of 1154 or 2.8 per cent of the total, about 1 per 1,000; on these claims were paid 5.9 per cent of all benefits paid ; and the average duration of benefit was 80.8 days which may be compa.red with an

average duration of benefit of 44 days. The average durat,ion of dis- ability due to circulatory diseases in this instance also was greater than that due to any other cause.

In view of the many circumstances which would incline the vital statistician to view group insurance mortality data as treacherous and nntrustworthy, it is of interest that an extensive mortality experience among men covered by that form of insurance known as industrial insurance shows an almost identical picture.

These data relate to deaths among individual policyholders whose occupations at death are recorded. Unfortunately, the number of lives at risk in each occupational classification cannot be obtained, so true death rates are not available. In consequence it is necessary to resort, to the use of a form of statement of mortality, which, while useful and truly informative, leaves much to be desired. The proportion of deaths from any cause, such as heart disease, in an occupational group is corrected for age and expressed in ratio to the proportion of deaths from that cause among all oc,cupied males. This figure is known as the “standardized ratio.”

In a study recently undertake:1 by the Statistical Bureau of the Metropolitan Life Insurance Company, under the direction of Dr. Louis 1. Dublin, there was determined the relation of occupation to 105,467 deaths which occurred during t’he three years, 1922 to 1924, among three and one quarter million male white indastrial policyholders.

The great majority, 90 per cent, of cardiac deaths were due to the cause of the international classification known as “Other Diseases of

the Heart, ” heart disease excluding pericarditis, acut,e endoca.rditis, acute myocarditis, and angina pectoris.

N~BLBEK OF I>EATIIS IN SPECIP'IEU _&GE PEKI~US Fp,ox ALL CAUSES END FKOM ~‘OT~IEX I)ISEASES OF THE HEART." R~IORTALITY ESPFXIEWE OF ;LIETKOPOLITAN LIFE INSCRANW

COMPANY ON WHITE MALE ISDUSTRIAL POLICYHOLDERS (Exc~vn~so RETIRED) 15 YEARS API'D OLDER, 1922 TO 1924

-___- KUMBER OF DEATHS

CAUSES OF AGES 15 DEATH YEARS 15 TO 24 2.5 TO d35 TO 44 4.5 TO 54155 TO 64 65 YE.wS

YEARS I'EARS YEARS YEARS / YEARS ASD OVER AXD OVER I

All eauees -11,927 105,467 12,153 15,041 Other diseases

19,656 / 25,054 21,636

of the heart 16,217 903 I 854 1 1,356 / 2,982 1 4,941 5,151

To this cause, “Other Diseases of the IIeart,” were assigned 16,217 deaths of individuals fifteen years or over, and it is to this class that the following data relate. The standardized ratios were computed for those deaths between the ages of fifteen and sixty-four years.

With the “ratio” of 100 for all occupied males, those for specific occu- pations ranged, strangely enough, from 180 among sailors of the navy to 37 among soldiers. These ratios may be ignored, however, as they

TABL

E VI

PERC

ENTA

GE

OF

DEAT

H~S

DUE

TO

“OTH

ER

DISE

ASES

OP

TH

E HE

ART”

O

F DE

ATIIS

FR

OM

ALL

CAUS

ES

IN

SPEC

IFIE

D OG

CUPA

TION

S M

ORT

ALIT

Y EX

PER.

IENC

E OP

M

ETRO

POLI

TAN

LIKE

INSU

RANC

E CO

MPA

NY

ON

WHI

TE

MAL

E IN

DUST

RIAL

PO

LICYH

OLDE

RS

15

YEAR

S AN

D OL

PEK.

19%

TO

19

%.

- .__

DE

ATHS

(15

YE

ARS

AND

OLDE

R)

OCCU

PATI

ON

OR

INDU

STRY

All

occu

patio

ns

cornb

iDed

(e

xclud

ing

retire

d)

sailo

rs (n

avy)

Boile

r m

aker

s M

erch

ants

and

store

keep

ers

Roofe

rs Co

oks

(hote

l an

d re

staur

ant)

Tailo

rs

and

other

clo

thing

m

ocke

rs Te

xtile

dyein

g, ble

nchin

g, an

d fin

ishing

m

ill wo

rkers

Wait

ers

and

hotel

se

rvants

Cl

erks

, bo

okke

epers

am

l off

ice

assis

tnrits

Ea

rbevs

an

d ha

irdre

sser

s Sh

oem

aker

s (co

bbler

s) Ho

stler

s an

d sta

blem

en

Brick

, tile

am

l ter

ra

cotta

wo

rkers

Huck

sters

and

pedd

lers

Plas

terer

s Ja

nitor

s an

d bu

ilding

em

ploye

es

Stor

e cle

rks

and

sales

men

Ag

ents,

ca

nvas

sers

and

sales

men

Tin

ners

(shop

) an

d tin

ware

wo

rkers

Long

shor

emen

an

d ste

vedo

res

ALL

CAUS

ES

105,4

67 21

8 3G

7 3,1

33

179

324

1,175

39

1 78

9 5,1

40

765

666

363

199

932

354

2.243

3,3

02

1,296

46

7 59

4

I’HER

DI

SEAS

ES

OF

THE

HEAR

.1’

16,21

7 10

G4

57

8 26

59

232 81

12

7 74

9 13

2 14

5 77

36

171 62

44

6 49

0 21

3 84

96

PERC

ENTA

GE

01’

DEAT

HS

FROM

OT

HER

DISE

ASES

0

CRUD

E FO

R AG

ES

15

YEAR

S AN

D O

LDER

15.4 4.6

17

.4 18

.4 14

.5 18

.2 1.9

.7 20

.7 16

.1 14

.6 17

.2 21

.8 21

.2 18

.1 18

.3 17

.5 19

.9 14

.8 16

.4 18

.0 16

.2

THE

HEAR

T

STAN

DARD

IZED

FO

R

AGES

15

TO

64

YE

ARS

13.2

23.8

17.0

16.9

16.3

16.3

16.2

15.5

15.4

15.2

14.8

14.7

14.7

14.6

14.6

14.5

14.5

14.4

14.1

74.1

14.0

STAN

DARD

IZED

RA

TIO

*

A’GE

S 13

TO

64

YE

ARS

luo.o

180.3

12

8.8

128.0

12

3.5

123.5

1.2

2.7

117.4

11

6.7

115.2

11

2.1

111.4

11

1.4

110.6

11

0.6

109.8

10

9.8

109.1

10

6.8

106.8

10

6.1

*The

pc

rcenta

gc

of

death

s (1

3.2)

show

n in

colum

n 4

for

all

occu

patio

ns

com

bined

wa

s tak

en

as

100.

The

stand

ardize

d pe

rcenta

ge

for

eacI1

oc

cupa

tion

divide

d by

13

.2 giv

es

the

Rtm

~rZa

.rdise

d Ra

tio.

454 THE AMERJCAS 3EART JOURXXL

are based upon small numbers of deaths and being corrected r‘or age do not accurately reflect the actual incidence of cardiac deaths in these two highly selected occupational groups.

These ratios, it must be clearly understood, are not death rates. They reflect only the importance of cardiac mortality in relation to other causes. Such indices, however, are of value in disclosing any tendency of occupation to induce an excessive mortality from any cause or causes.

The best extensive occupational mortality data of recent date now available are to be found in the report of the Registrar General of England and Wales for the period 1921-1923.

Among 164 occupational classes of those males dying between the ages twenty and sixty-five years but 16 classes showed significant standardized mortality rates from valvular diseases of the heart in excess of that for all occupied and retired males, and 21 classes, an excessive mortality from “Other Diseases of the Heart. ”

In only a few classes was the excess mortality at all marked. It was for other diseases of the heart particularly notable in those classes’ ex- posed to a silica hazard and with bartenders. The association of heart disease and a silica hazard was not evident in the American data.

It is possible, even probable, that there is in this country a higher degree of mobility of labor than in Great Britain, a greater tendency of workers to shift from one form of employment to another more congenial or better suited to physical capacity.

It may thus be seen that whatever may be the importance of the part played by occupation in the development or aggravation of cardiac incapacity in particular, individual cases, there is no considerable evidence that certain occupations are conducive to high death rates in the battle with the new captain of the men of death.