cause-specific mortality by marital status and social class in finland during 1969–1971

Soc. Sci. & Med., Vol. 13A. pp. 69t to 697 Pergamon Press Lid 1979. Printed in Great Britain

CAUSE-SPECIFIC MORTALITY BY STATUS AND SOCIAL CLASS IN

D U R I N G 1969-1971

MARITAL FINLAND

MARKKU KOSKENVUO, SEPPO SARNA, JAAKKO KAPRIO

Department of Public Health Science, University of Helsinki, Haartmaninkatu 3 , SF-00290 Helsinki 29, Finland

and

JOUKO I~NNQVIST

Psychiatric Clinic, Helsinki University Central Hospital, Lapinlahdentie, SF-00180 Helsinki 18, Finland

Abstract--Variation in cause-specific mortality by marital status and social class in Finland during t969 1971 was studied. Greatest variations were found for violent deaths, infectious diseases and alcohol-associated diseases. If other factors were kept constant, elimination of differences in mortality by social class would reduce total mortality by 21%. The corresponding figure for marital state differences would be 13%. However, differences in mortality rates between marital status categories were greater than between social class categories. It was concluded that both selective forces and environmental factors influence these mortality differences, but further clarification should be based on prospective studies of life-changes, environmental factors and morbidity.

INTRODUCTION

Marital status, current occupation and social class are basic demographic data which reflect psychosocial characteristics. These can therefore be used as easily available variables of a psychosocial nature.

Mortality rates vary by marital status and social class. Mortali ty rates have been commonly found to be lowest for married persons [ i - 8 ] and for persons belonging to the highest social class [9-13]. In Eng- land and Wales young widowed persons have the highest mortality rates [13], while the mortality rates of divorced persons do not differ from those of single persons. In Finland on the other hand, divorced persons have higher mortality rates than single persons [I4]. Variation of mortality rates by social class is nearly twofold both in Finland and England and Wales [13, 14].

In a previous paper [14] we have analysed overall mortality rates for natural and violent causes in Finland by marital status and by social class simultaneously. It was found that mortality rates in different marital status-social class combinatiofis varied most in younger (25-44 year olds) and least in older age-groups (65-84). Variation was greater for morta-

Abbreviations: Marital status: S = single; M = married; W = widowed; D = divorced. Social class [17, 18]: 1 = upper professional; 2 = lower professional; 3 = skilled worker; 4 = unskilled worker; 5 = farmers. RR = mortality rate ratio = mortality rate of marital state or social class with the highest rate/mortality rate of marital state or social class with the lowest rate. MSR = (marital status category with highest mortality rate)/(marital status category with lowest mortality rate). SCR = (social class category with highest mortality rate/(social class category with lowest mortality rate).

691

lity rates from violent causes than from natural causes.

Variations in mortality rates have been attributed either to selective forces or to environmental differences between social classes or marital status. Selec- tive forces would cause persons with a greater liability to disease to remain in or change to less favourable marital states or social classes, thus resulting in variations in mortality rates. On the other hand, environmental differefices of risk factors of disease between marital status or social classes would cause mortali ty rate variation, even though initial liability to disease in the population was equally distributed. Therefore, we hypothesized that, if mortality rates varied by marital status or social class to the same extent by most causes of death, and the same marital state or social class has consistently the highest mortality rates, selective forces would have been the most in- fluential in moulding mortality pattern in Finland. Contrariwise, if mortality rate variation differed by cause of death, and varying marital states or social classes had highest cause-specific mortality rates, environmental differences between marital status or social classes would have been more important in affecting mortality.

In this paper, the mortality rates of 25-64 year-olds by marital status and social class in main diagnosis groups will be presented. For deaths from natural causes, classification by principal groups of the Inter- national Classification of Diseases [15] were used and for deaths from violent causes, subgrouping was used.

MATERIALS AND METHODS

The mortality data for the 25-64 year-olds was based on 44,548 (32.3% of all deaths) death certificates

692 MARKKU KOSKENVUO, SEPPO SARNA, JAAKKO KAPRIO and JOUKO LONNQVIST

for the years 1969, 1970 and 1971 in Finland. The reference popula t ion was based on 1970 census returns [16]. The materials and methods have been reported previously [14] and the composi t ion of social classes in F in land has been described elsewhere [17]. Mortal i ty rates per 100,000 per annum were calculated by direct s tandardisat ion by sex, 5 year agegroup and social class or mari tal status using the corresponding reference popula t ion figures. To study age trends, results for the age groups 25-44, 45-54 and 55-64 were also calculated.

Classification of causes of death was based on the 8th revision of the ICD [15]. Causes of death were grouped into main disease groups I -XVI for na tura l causes, and for deaths from violent external causes were grouped by a slightly modified version of the ICD "A" list. For cardiovascular diseases, myocardial disorders (ICD rubrics 410-429) and cerebrovascular diseases (ICD rubrics 430--438) were also considered separately. Main disease groups IV, XI, XII, XIII, XIV, XV and XVI and certain rare external causes were omitted. Altogether 1332 death certificates (3.0~) were excluded.

Social class had been coded at the Central Statisti- cal Office based on the occupational da ta on the death certificate, Nonemployed and retired persons were classified by their former occupation, or the occupation of their supporter, which was the case for non-employed marr ied women. The occupation, and thus social class, was unknown in 2 .2~ of all death certificates. Data was missing more often for women than men. Compar isons between social class as recorded on the death certificate and social class

recorded at t h e 1970 census have not been made. These are, however, coded by the same procedure [173.

To assess possible differences in accuracy of cause of death certification, the propor t ion of autopsies (both medical and medicolegal) by sex, age-group and mari tal status or social class was analysed. Analysis was done separately for deaths from natura l causes and violent causes.

The propor t ion of autopsies (medical and medicolegal) by age and sex in the mari tal status and social class categories for deaths from natura l causes is shown in Table 1. The propor t ion of autopsies de- creased with age, and was generally greater for men than for same-aged women in the same mari tal status or social class category. In all age-groups for bo th men and women, farmers had the lowest propor t ion of autopsies compared to other social classes. Divorced persons had the highest autopsy rates of all mari tal status categories in all sex-age groups.

The autopsy rates for deaths from violent causes (Table 2) were higher than for deaths from natural causes. The decrease with age in autopsy rates was less clear for violent deaths and no meaningful sex differences can be seen. Again farmers had the lowest autopsy rates for all social classes, while autopsy rates were of the same order in all mari ta l status categories.

RESULTS

The variat ion of mortal i ty rates by mari tal status or social class in men and women is given in Tables 3~5. For each marital state and social class, the standard-

Table 1. Proportions of autopsies by age, social class and marital status for deaths from natural causes. Men and women

Social class Marital status Age group 1 2 3 4 5 S M W D

Men 25-44 63.6 57.8 59.6 59.5 45.5 60.2 54 .1 45.5 78.7 45-54 53.1 45.9 49.9 43.8 30.4 44.9 42 .1 46.8 66.! 55-64 40.8 40.8 40.5 33.2 21 .1 33.9 32.4 38.3 53.7

Women

25-44 54.6 50.0 54.0 48.8 43.4 49.6 49.7 54.8 61.6 45-54 49.4 43.7 44.8 39.7 25.7 40.1 38.1 37.6 53.9 55-64 41.0 40.0 38,5 34.2 20,4 35.3 30,9 33.6 49.8

Table 2. Proportions of autopsies by age, social class and marital status for deaths from violent causes. Men and women

Social class Marital status Age group l 2 3 4 5 S M W D

Men 25-44 85.4 87.5 87.6 84.4 75.3 83.7 85.2 85.3 90.8 45-54 89.5 85.7 88.2 86.3 71.3 83.2 83.5 91.1 90.9 55-64 83.3 85 .1 89.3 79.2 75.9 79.3 83.2 85.7 81.3

Women

25-44 90.6 90.6 91.5 89.9 82.6 86.6 89.5 91.3 100.0 45-54 90.0 96.4 91.7 82.5 76.9 87.3 86.4 95.7 93.8 55-64 83.3 91.5 83.3 83.0 78.3 80.2 81.9 84.3 92.5

Cause-specific mortality by marital status and social class

Table 3. Mortality rates by marital status. Men 25-64 years

693

S M W D RR MSR

Natural causes of death I Infections 43.4(152) 10.3(266) 30.5(27) 54.1 (53) 5.3 D/M

II Cancer 203.6 (677) 180.5 (4680) 230.9 (274) 277.6 (274) 1.5 D/M " III Endo., Nut. & Metab. dis. 18.1 (81) 6.7(172) 10.8(12) 21.7(20) 3.3 D/M V Mental disorders 22.5 (90) 1.9 (50) 8.6 (5) 75.0 (67) 38.8 D/M

VI Nervous system 23.0 (104) 5.5 (142) 3.6 (6) 21,7 (20) 6.3 S/W VII Circulatory 593.2(1985) 443.5(11528) 665.1(721) 741.0(717) 1.7 D/M

ICD: 410-429 443.4 343.5 479.6 576.1 1.7 D/M ICD: 430-438 95.6 64.7 111.7 111.7 1.7 W-D/M

VIII Respiratory 132.1 (438) 33.4(865) 76.6 (94) 147.6 (142) 4.4 D/M IX Gastrointestinal 39.2 (145) 19.2 (497) 47.9 (44) 85.0 (80) 4.4 D/M X Genito-urinary 17.6(68) 9.3(240) 11.7(15) 17.5(16) 1.9 S/M

Total 1108.1 (3812) 7172(18623) 1090.2(1204) 1454.7(1400) 2.0 D/M

Deaths from accidents, poisonings and violence. External cause of death

1. Traffic 91.2(441) 44.9(1131) 410.9(55) 131.9(110) 9.2 W/M 2. Poisonings 53.0(220) 10.0(258) 41.8(25) 139.2(124) 13.9 D/M 3. Falls 16.3 (65) 5.1 (131) 11.1 (10) 41.1 (38) 8.0 D/M 4. Fires 19.4 (79) 1.8 (46) 13.1 (5) 26.4(24) 14.3 D/M 5. Drownings 27.9(130) 6.5(614) 16.7(4) 49,3(41) 7,6 D/M 6. Suicides 112.4(554) 40.1 (1022) 267.2(71) 153.8(129) 6.7 W/M 7. Homicides 14.2(73) 2.4(59) 11.1 (2) 34.1 (31) 14.5 D/M

Total 378.3(1764) 124.2(3151) 798.0(188) 661.0(571) 6.4 W/M

Standardized rates per 100,000 and number of deaths. Rate ratios (RR) for highest to lowest marital status category (MSR).

ized death rate and number of deaths is given by cause of death. The ratio (RR) of the highest to lowest rate and the mari ta l state (MSR) or social class (SCR) categories with the respective rates are given on the right-hand side of the tables.

Marital status The highest rate ratios for men (Table 3) were men-

tal disorders, nervous system diseases and infections for deaths from natural causes, while for violent deaths highest ratios were for homicides, fire acci-

Table 4. Mortality~rates by marital status. Women 25-64 years

S M W D RR MSR

Natural causes of death I Infections 11.2 (53) 4.3 (93) 7.5 (38) 11.4 (18) 2.6 D/M

II Cancer 138.7 (652) 115.2 (2522) 111.4 (678) 144.2 (238) 1.3 D/W III Endo., Nut. & Metab. dis. 10.9(55) 9.0(187) 13.6(75) 8.8(14) 1.6 W/D V Mental disorders 2.7 (13) 0.5 (11) 0.9 (8) 5.5 (9) 10.5 D/M

VI Nervous system 16.0 (77) 4.9 (106) 6.2 (28) 9.7 (16) 3.3 S/M VII Circulatory 189.7 (910) 158.9 (3264) 227.6 (1382) 232. (381) 1.5 D/M

ICD: 410-429 96.7 78.4 110.0 117.8 1.5 D/M ICD: 430-438 60.9 53.9 78.7 70.8 1.5 W/M

VIII Respiratory 34.2(162) 11.1 (230) 22.4(123) 27.1 (45) 3.1 S/M IX Gastrointestinal 15.7 (73) 10.8 (235) 9.3 (63) 19.9 (33) 2.1 D/W X Genito-urinary 19~6 (93) 9.8 (215) 16.4 (80) 17.6 (29) 2.0 S/M

Total 456.0 (2169) 332.4 (7042) 423.4 (2518) 487.2 (799) 1.5 D/M


1. Traffic 16.6 (82) 10.5 (254) 41.7 (78) 26.0 (37) 4.0 W/M 2. Poisonings 1.2 (6) 1.1 (27) 2.4 (5) 5.4 (9) 4.9 D/M 3. Falls 3.9(19) 1.5(33) 2.7(14) 3.1 (5) 2.7 S/M 4. Fires 1.2 (6) 0.5 (13) 7.6 (3) 4.4 (6) 14.3 W/M 5. Drownings 3.0 (14) 0.5 (13) 1.0 (6) 2.5 (3) 5.9 S/M 6. Suicides 25.6 (122) 11.2 (272) 15.8 (68) 34.9 (52) 3.1 D/M 7. Homicides 1.0(5) " 1.2(31) 8.0(4) 8.1 (12) 8.1 D/S

Total 56.9 (275) 28.9 (700) 84.5 (191) 93.0 (138) 3.2 D/M

Standardized rates per 100,000 and number of deaths. Rate ratios (RR) for highest to lowest marital status category (MSR).


dents and poisonings. For external causes all ratios were greater than 6.0, while lowest ratios were for cancer and cardiovascular diseases. It may be noted that for mental disorders, alcoholism was the main single cause of death. Married men had generally the lowest rates, while divorced men had most often the highest rates.

The general trend over age for each cause of death was a decrease in the magnitude of the rate ratio. The decrease was clearer for natural causes of death, while for external causes fire accidents and homicides showed no decrease with age.

For women (Table 4), the rate ratios were smaller than for men, but the same disease groups showed the highest and lowest ratios for natural causes. For violent causes fires and homicides had the highest ratios, the smallest being for falls and suicides. Mar- ried women had the lowest rates for most categories, while divorced or single women had the highest rates.

Interestingly widowers had the highest rates for traffic accidents and suicides, the two most common causes of violent "death, while widows had the highest rate for traffic accidents. If the mortality rates of all marital state groups were at the same level as those of married persons, it was calculated that the overall death rate from natural causes would be 10~ lower for men and 9~o for women. For violent causes the total death rate would be 31~o lower for men and 24~ lower for women.

Social class

For men (Table 5) ratios of highest to lowest social class specific death rates were of the same order as for marital status. Mental disorders, respiratory diseases, nervous system diseases and infections had the highest ratios for natural causes, while the corre-

sponding classes of external causes were homicides, fires and poisonings. In all categories unskilled workers (social class 4) had the highest rate, while upper professionals had generally the lowest rate.

Mortali ty rate ratios showed for natural causes a fairly consistent decrease with age, while for external causes the trend was a less clear decrease with age. Traffic accidents, drownings and homocides were the only external causes to decrease with age.

Table 6 shows the variation by social class of mortality rates for women. The overall amount of variation is lower than that for men, the highest ratio of 4.0 being for mental disorders. For violent deaths poisonings, fires and falls show the most variation in mortality rates. No clearcut patterns as to which social classes had lowest and highest rates could be seen for women. For all causes variation in rates de- creased with age.

If the mortality rates in other social classes were the same as for social class 1, which had in general the lowest rates, the overall mortality would have been 21~ smaller for natural causes and 40~ among violent causes for men. For women, the reduction would have been 12~o for natural causes. For women social class 1 did not have the lowest rate for violent causes but if all social classes had the same rate as farmers (social class 5), mortality would have been 24~o lower.

DISCUSSION

Methods

In a previous paper [14] overall mortality rates by social class and marital status for natural deaths and violent deaths in 25-84 year-olds were described. It was found that little variation occured in 65-84

•able 5. Mortality rates by social class. Men 25-64 years

1 2 3 4 5 RR SCR

Natural causes of death I Infections 9.8 (24)

II Cancer 142.8 (323) III Endo., Nut. & Metab. dis. 7.9 (19) V Mefltal disorders 2.1 (6)

VI Nervous system 6.5 (14) VII Circulatory 398.7 (886)

ICD: 410-429 305.3 ICD: 430-438 61.5

VIII Respiratory 17.7 (41) IX Gastrointestinal 30.5 (72) X Genito-urinary 6.4 (15)

Total

13.7 (7.3) 17.1 (185) 28.7 (124) 10.7 (80) 2.9 4/1 173.0(904) 200.4(2147) 250.5(1134) 164.9(1362) 1.8 4/1

10.5 (57) " 7.7 (91) 13.2 (54) 8.9 (62) 1.7 4/3 2.9 (16) 6.7 (80) 23.0 (93) 1.7 (13) 13.9 4/5 5.6 (31) 6.7 (77) 17.5 (70) 12.1 (69) 3.1 4/2

521.3(2730) 444.1(4812) 613.6(2716) 447.5(3637) 1.5 4 / 1 ' 404.4 339.6 477.8 338.6 1.6 4/1

73.0 67.2 87.5 71.3 1.4 4/1 30.8 (158) 46.5 (494) 99.2 (444) 43.9 (359) 5.6 4/1 26.4(143) 23.0(257) 32.1(138) 17.7(136) 1.8 4/5 10.8 (57) 12.2 (135) 14.6 (62) 8.9 (69) 2.3 4/1

627.5(1413) 806.7(4233) 771.9(8368)1102.5(4879) 725.7(5845) 1.8 4/1


I. Traffic 36.3(100) 54.0(311) 2. Poisonings " 7.2 (20) 9.2 (53) 3. Falls 5.2(13) 7.4(40) 4. Fires 0.7 (2) 2.7 (16) 5. Drownings 4.1 (11) 6.5(37) 6. Suicides 44.1 (123) 47.7 (274) 7. Homicides 0.3 (1) 2.7 (16)

Total 107.6 (297) 143.6 (823)

52.6 (647) 102.1 (390) 45.0(268) 2.8 4/1 16.9 (205) 67.1 (262) 11.4 (71) 9.4 4/1 8.9 (104) 14.2 (57) 4.0 (26) 3.5 4/5 3.4 (43) 18.6 (74) 3.3 (16) 27.3 4/1

11.4 (140) 27.6 (101) 7.8 (42) 6.7 4/1 46.4 (566) 114.2 (432) 60.3 (339) 2.6 4/1 4.5 (57) 19.3 (71) 2.7 (18) 66.4 4/1

163.8(2005) 416.2(1589) 146.8(852) 3.9 4/1

Standardized rates per 100,000 and number of deaths. Rate ratios (RR) for highest to lowest social class category (SCR).

Cause-specific mortality by marital status and social class 695

Table 6. Mortality rates by social class. Women 25-64 years

1 2 3 4 5 RR SCR

Natural causes of deaths I Infections

II Cancer III Endo., Nut. & metab, dis. V Mental disorders

VI Nervous system VII Circulatory

ICD: 410-429 ICD: 430~38

VIII Respiratory IX Gastrointestinal X Genito-urinary

Total

2.7 (6) 3.8 (29) 6.6 (64) 6.3 (36) 7.5 (57) 2.7 5/1 126.4(268) 122;1 (891) 132.8 (1275) 122.1 (680) 109.6(896) 1.2 3/5 "

7.1 (16) 9.4 (70) 8.7 (82) t4.4 (75) 10.8 (78) 2.0 4/1 1.3 (3) 0.7 (5) 1.0 (10) 2.6 (14) 1.0 (7) 4.0 4/2 6.3 (13) 5.1 (38) 6.1 (59) 8.8 (4.2) 8.9 (57) 1.8 5/2

131.1(266) 142.9(981) 179.8(1689) 205.2(1169) 183.4(1541) 1.6 4/1 67.9 73.7 91.7 96.5 90.8 1.4 4/1 44.3 45.0 58.1 75.1 61.0 1.7 4/1

8.9 (19) 10.5 (73) 13.6 (129) 25.9 (142) 19.1 (156) 2.9 4/1 17.4(37) 10.1 ( 7 5 ) 14.6(139) 12.6(67) 8.6(68) Z0 1/5 13.3(28) 1 1 . 7 ( 8 8 ) 13.7(131) 11.3(63) 11.4(93) 1.2 3/4

323.4(676) 324.5(2316) 386.1(3669) 419.4(2342) 370.2(3023) 1.3 4/1


1. Traffic 13.6(33) 12 .0(104) 14.4(147) 17.1 (77 ) 10.2(75) 1.7 4/5 2. Poisonings 0.3 (1) 1.8 (15) 1.2 (12) 2.9 (14) 0.6 (4) 10.6 4/1 3. Falls 1.0 (2) 1.9 (15) 2. ! (20) 3.9 (20) 0.9 (8) 4.1 4/5 4. Fires 0.3(1) 0.7(5) 1.l (11) 1.6(7) 0.7(4) 5.0 4/1 5. Drownings 1.3 (3) 0.7 (7) 1.l (11) 1.0 (5) 1.2 (7) 1.9 1/2 6. Suicides 21.8 (56) 12.1 (107) 15.5 (156) 17.7 (83) 12.8 (88) 1.8 1/2 7. Homicides 1.2 (3) 1.4 (12) 2.0 (21) 2.0 (8) 0.7 (5) 2.9 3-4/5

Total 45.6 (113) 32.1 (282) 41.3 (418) 49.2 (230) 28.8 (204) 1.7 4/5

Standardized rates per 100,000 and number of deaths. Rate ratios (RR) for highest to lowest social class category (SCR).

year-olds and therefore this agegroup was excluded from this study. Under 25 year-olds were excluded as their social class is generally based on parental classification.

When the present material was divided by sex and cause of death, simultaneous analysis by social class and marital status was not possible for all causes of death, resulting from too few cases in most cause of death categories. Therefore analysis by social class and marital status was carried out separately. The strong dependence of these two variables and their classification had been described and discussed previously [14]. For men the meaningful finding was an increasing proportion of single and divorced men with decreasing social class.

The accuracy of diagnosis in death certificates in Finland has been studied [19, 20]. In this study, of im- portance is whether differences in accuracy occur in different marital states or social classes. One variable assessing accuracy of death certification is the autopsy rate. The autopsy rate (Table 1) for deaths from natural causes was highest for 25-44 year-olds, and slightly higher for men than women. As the variation of mortality rates was greatest in youngest agegroups and more so for men than women, it would not be a confounding effect. Farmers had lower autopsy rates than other social class categories, who had very- similar rates. This is explained by the lower autopsy rates in rural areas [20]. Divorced persons had higher autopsy rates than persons in other marital status categories, which is probably due to fact that divorced persons form a smaller proportion of social class 5 than other classes [14]. On the other hand divorced persons may behave differently with respect to health services and so die more often in situations leading to autopsy. Autopsy rates for deaths from violent

causes (Table 2) were higher than for deaths from natural causes, which is explained by medicolegal procedures in Finland [21].

Occupational mortality data from England and Wales has been shown to be biased [13] due to differences in occupational classification on census returns and death certificates. A comparable study has not been published for Finnish data. The same coding procedure, however is used for both data sets [17]. The social class classification was based on the occupation recorded on the death certificate by the treat- ing physician based on information reported by the patient or his relatives.

The death certificate is sent to the local population registry, where the information is checked before it is sent to the Central Statistical Office for coding and registration. The occupation recorded on the death certificate may not necessarily correspond to the main occupation in the occupational history of the deceased but might be the last occupation or the one with the most social stature. This type of error would probably lessen differences in mortality rates by social class.

Results

In this study we have attempted to explore the variation of mortality rates by marital status or social class by cause of death in the working-aged population in Finland during 1969-1971, and to discover whether the variation in rates is attributable to certain causes of death or is the variation similarly distributed among all causes. If mortality varies consider- ably by marital status or social class for a specific cause of death, it is probable that some environmental factor(s) associated with this cause of death also varies by marital status or social class. In such a case


selective forces are less likely to be operating. The two mechanism, however, probably both operate over time, their relative influence varying with the dynamic process of the disease. For example abuse of alcohol may lead to divorce, but simultaneously increase acci- dent-proneness. On the other hand disability and disease will reduce occupational possibilities leading to a vicious circle involving high levels of risk factors, poor occupational history and low use of medical facilities.

The distribution of marital statuses and social classes with the highest and lowest mortality rates conforms for most causes of death to the overall pattern described earlier [14]. Divorced men and women generally had the highest rates, while married persons had the lowest for nearly all age-groups and causes of death. For social class, men showed fairly consistently that unskilled workers have the highest rates, while upper professionals and farmers had the lowest rates. For women social class showed the least clearcut patterns. In part this may be explained by the fact that non-gaiiafully employed married women are classified by their husbands' occupation [17], thus blurring any effect their own social class may have.

The greatest variation in mortality rates was found fairly consistently for both marital status and social class to be restricted to the main categories of mental disorders (V), disorders of the nervous system (VI), respiratory diseases (VII) and infectious diseases (I). Three of these categories are relatively homogenous with respect to the individual causes of death within the categories [22]. For instance, alcoholism (ICD 303) accounted for 78% of all deaths for mental disorders and tuberculosis (ICD 010--019) also for 78~o of deaths in category I. Infectious processes accounted also for the majority of deaths from respiratory diseases, as the pneumonias and bronchitis (ICD 485-491) with emphysema and asthma (ICD 492-493) formed nearly 80% of deaths in this category. In con- trast, no individual diagnosis in the category of nervous system diseases accounted for any significant proportion of deaths.

Cancer and cardiovascular diseases showed least variation, with at most 1.8-fold variation for cancer and 1.7-fold for cardiovascular disorders. It has been estimated that the majority of cancers are caused by environmental agents [23]. In the light of the present results, it appears that these agents are fairly evenly distributed with respect to marital status and social class, while conditions due to infective agents or alcohol associated disorders are more unevenly distributed. In an international comparison of the variation of cause-specific mortality rates [24], large variations for respiratory tuberculosis and certain specific cancers were found, while all neoplasms showed little intercountry variation.

For external causes of death variation in rates was high for nearly all causes. For men, deaths from acci- dental fires and poisonings, as well as homicides had the largest variations in mortality rates. Alcohol poisonings formed four-fifths of all poisonings, while alcohol has been shown to be involved in the majority of homicides [25] in Finland. In 1967 in over 80% of victims of fire accidents, blood alcohol concen- trations over 1%o were measured [26]. Divorced persons, in particular, use to a much larger degree hospi-

tal services for alcohol associated diseases [27]. Thus large alcohol involvement is seen for those causes with large variation in mortality rates, indicating the role of alcohol as a definite risk factor for mortality.

The low mortality rates for married persons may be due partly to lower risk factor levels. The effect of marriage, and in particular remarriage of divorcees and widow(er)s should also be considered. It would be interesting to have data on effect on family stability, i.e. what are mortality differences between married persons according to family stability.

In a Finnish study [28] widowed persons had a 1.6-fold hypermortality during the first two years after the spouse's death. After that their mortality returned to the same level as population's mortality. So it seems that selective forces have a minimal effect on the increased mortality of widowed persons.

The decrease in variation of mortality with age in- dicates that environmental factors that vary by marital status or social class play a lesser role in mortality in older age-groups. This trend did not occur for violent deaths, where variation remained fairly constant at all ages.

In conclusion, considerable variation in mortality by social class and marital status for a number of causes of death exist in a relatively recently industria- lized welfare state. The analysis of results seem to indicate the existence both of selective influences and of environmental variation. Because death is the end- point of a complicated dynamic process, an analytical study would necessitate results from longitudinal studies of life-changes, environmental changes and morbidity. The results, however, strongly suggest that a viable and intact family has a powerful positive effect on the health behaviour of its members. If all other factors were kept constant, the elimination of social class differentials would reduce mortality 21% and elimination of marital state differentials--a less realistic possibility--would reduce mortality 13%.

Acknowledoement--This study has been supported by a grant from the Yrjti Jahnsson Foundation.

REFERENCES

1. Kraus A. S. and Lilienfeld A. M. Some epidemiologicat aspects of the high mortality rate in the young widowed group, d. chron. Dis. 10, 207-217,, 1959.

2. Sheps M. C. Marriage and mortality. Am. J. Publ. Hlth 51, 547-555, 1961.

3. Berkson J. Mortality and marital status. Am. J. Publ. Hlth 52, 1318-1329, 1962.

4. Young M., Benjamin B. and Wallis C. The mortality of widowers. Lancet 1,454-456, 1963.

5. Rahe R. H., McKean J. and Arthus R. J. A longitudinal study of life change and illness. J. Psychosom. Res. 10, 355-366, 1967.

6. Parkes C. M., Benjamin B. and Fitzgerald R. G. Broken heart: a statistical study of increased mortality among widowers. Br. Med. J. 1, 740-743, 1969.

7. Gove W. R. Sex, marital status and mortality. Am. J. Sodol. 79, 45~67, 1973.

81 Jenkins C. D. Recent evidence supporting psychologic and social risk factors for coronary disease. N. Enol. J. Med. 294, 987-994; 1033-1038, 1976.

9. Logan W. P. D. Social class variations in mortality. Br. J. prey. Social Med. 8, 128-137, 1954.

Cause-specific mortality by

10. Stockwell E. G. Use of socioeconomic status as a demographic variable. Publ. Hlth Rep., Wash. 81, 961-966, 1966.

11. Antonovsky A. Social class, life expectancy and overall mortality. Milbank mere. Fund q. bull. 45, 31-73, 1967.

12. Wald N. Morbidity and mortality in relation to social class. Lancet i, 259, 1972.

13. Occupational mortality, Decennial supplement, 1970- 1972, England and Wales. A publication of the Govern- ment Statistical Service, Series DS No. 1, London, 1978.

14. Koskenvuo M., Sarna S. and Kaprio J. Mortality by marital status and social class in Finland during 1969 1971. Mortality from natural and violent causes. Scand. J. Social Med. 6, 132143, 1978.

15. World Health Organisation. International Classifica- • tion of Diseases, Eight (1965)revision. WHO: Geneva, 1967.

16. Central Statistical Office of Finland. Census 1970, Part 9, Occupation and Social Class. Central Statistical Office of Finland, Helsinki, 1974.

17. N~iyh~i S. Social group and mortality in Finland. Br. J. prey. soc. Med. 31, 321-327, 1977.

18. Central Statistical Office of Finland. Occupation Cata- loque. Central Statistical Office of Finland, Helsinkk 1972.

19. Isotalo A. and Korpela A. Reliability of statistics on causes of death and the diagnostic basis on death certi- fications (English summary). J. Finn. Med. Ass. 18, 1537, 1963.

marital status and social class 697

20. Penttil~i A. Mortality from arteriosclerotic and other degenerative heart diseases in Finland in 1968. Health Services Research of the National Board of Health in Finland 12/1974, Helsinki, 1975.

21. Poikolainen K. Alcohol poisoning mortality in four nordic countries. The Finnish Foundation for Alcohol Studies, Helsinki, 1977.

22. Central Statistical Office of Finland• Causes of death in Finland 1970. Central Statistical Office of Finland, Helsinki, 1973.

23. Berlin N. Cancer and the national cancer institute: today and tomorrow (Editorial). J. chron. Dis. 30, I-6, 1977.

24. Gentleman J. F. and Farkes W. F. The identification of environmental factors in various disease processes. by analysing the variation in disease-specific mortality rates. J. chron. Dis. 30, 477-487, 1977.

25. Virkkunen M. Alkoholi ja henkirikokset (Alcohol and homicides). Alkoholipolitiikka 39, 86, 1974.

26. Virkkunen M. and Alho A. R. Deaths caused by fire or carbon monoxide in 1967 in Finland (English summary). J. Finn. Med. Ass. 24, 1213, 1969.

27. Salaspuro A. The strain on health services caused by the use of alcohol. Proceedings of 21st International Institute on the Prevention and Treatment o f Alcoho- lism, Helsinki, 1975.

28. Koskenvuo M. Mortality and the causes oF death among spouses (English summary). Thesis, Publica- tions of the Department of Public Health Science M 30, Helsinki, 1978.

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