Sarah Wamala Inst. För Folkhälsovetenskap, Avd för Preventiv medicin Karolinska Institutet

Abstract
Socioeconomic Status and Cardiovascular Vulnerability in Women: Psychosocial, Behavioral, and Biological Mediators

Sarah P. Wamala Inst. För Folkhälsovetenskap, Avd för Preventiv medicin Karolinska Institutet

Cardiovascular disease (CVD) is the leading cause of death in both men and women in the industrialized world, and represents a major health and economic burden. CVD is the disease which is invariably more frequent in men and women of lower than higher socioeconomic status (SES), than any other disease. In spite of the overall decline in CHD rates, socioeconomic differences persist, and may even be widening, particularly in women. Women are more socioeconomically disadvantaged than men, and the attributable fraction of low SES for CVD, may be higher in women than in men. Unfortunately, relatively little is known about the association between SES and CVD in women.

The aims of the thesis included studying the association between SES and CVD risk in women, and to estimate the relative contribution of social and behavioral factors to the socioeconomic disparities in women's CVD. In addition the effects of SES and childhood circumstances on CVD prognosis, and the associations between SES and physiological risk factors for CVD (obesity, atherogenic lipid profile and hemostatic dysfunction) in women were studied.

The data used in this thesis were from the Stockholm Female Coronary Risk (FemCorRisk) Study. The FemCorRisk study is a population-based case-control study which comprises all women aged 65 years or younger who were admitted for an acute event of CHD between 1991 and 1994 in any of the coronary care units of all hospitals in the greater Stockholm area. Healthy controls from the census register were matched with CHD patients with regard to age and catchment area.

The results showed that low SES increases vulnerability to CHD in women. Low SES (as measured by low educational attainment and low occupational status) had a substantial impact on both cardiovascular risk, and physiological risk factors for CHD (obesity, atherogenic lipid profile and hemostatic dysfunction). After adjustment for age, women with only mandatory school education (¾9 years) had a two-fold increased risk for CHD as compared to women who had attained college/university. Psychosocial stress, unhealthy behaviors and poorer physiological risk factor profiles were the factors which explained the association between low education and increased CHD risk. Of these factors, psychosocial stress and unhealthy behaviors were the most important. Un/semi-skilled workers had a four-fold increased risk for CHD as compared to executives/professionals after adjustment for age. Traditional cardiovascular risk factors and work-related factors however, did not "fully" explain why women with lower status jobs had an increased risk of CHD. There was no indication of low SES being associated with a poorer prognosis of CHD. Adverse childhood circumstances (as measured by short stature) on the other hand, showed a strong negative effect on CHD prognosis. Low SES was also associated with obesity, atherogenic lipid profile (mainly low HDL) and hemostatic dysfunction in the healthy control women.

The results in this thesis underline the importance of low SES in the etiology of CVD in women. The factors explaining the CVD-SES association in women range from adverse childhood circumstances, negative personality, poor social relations, unhealthy behaviors, poorer biological risk factor profiles, to stressors that operate both at work and at home.

The fact that these findings are based on women living in Sweden raises a major concern for re-considering the substantial importance of SES in the etiology of CVD. In Sweden there is a tradition of economic policies which are geared to reducing the gap between the "better-off" and the "disadvantaged". These economic policies unfortunately, have not been successful in reducing the socioeconomic inequalities in health. In fact, these inequalities are increasing and widening, especially for women. More over, the impact of socioeconomic status on health in women, who occupy the most vulnerable socioeconomic positions, has been given relatively little attention. Because of the structural positions that women occupy in society, one of the challenges for future preventive efforts is to create favorable conditions for socioeconomically deprived women. Such efforts should combine both work and non-work related factors.

I Wamala SP, Mittleman AM, Schenck-Gustafsson K, Orth-Gomér K. Potential explanations for the educational gradient in coronary heart disease: A population-based case control study of Swedish women. American J Public Health 1999;89(3):315-321.

II Wamala SP, Mittleman AM, Horsten M, Schenck-Gustafsson K, Orth-Gomér K. Job control and the occupational gradient in coronary heart disease risk in women.1999: In review.

III Wamala SP, Mittleman AM, Horsten M, Schenck-Gustafsson K, Orth-Gomér K. Short stature and prognosis of coronary heart disease in women. J Internal Medicine 1999;245:(in press).

IV Wamala SP, Wolk A, Orth-Gomér K. Determinants of obesity in relation to socioeconomic status in middle aged Swedish women. Preventive Medicine 1997;26:734-44.

V Wamala SP, Wolk A, Schenck-Gustafsson K, Orth-Gomér K. Socioeconomic status and lipid profile in middle aged women in Sweden. J Epidemiology Community Health 1997;51(4):400-407. Erratum: J Epidemiol Community Health 1998;52:340.

VI Wamala SP, Mittleman AM, Horsten M, Eriksson M, Hamsten A, Silveira A, Schenck-Gustafsson K, Orth-Gomér K. Socioeconomic status and determinants of hemostatic function in healthy women. Arteriosclerosis Thrombosis Vascular Biology 1999; (in press).