Socioeconomic status and cardiovascular vulnerability in women : psychosocial, behavioral and biological mediators

Abstract

Background: 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. Coronary heart disease (CHD), one of the most common of the cardiovascular diseases, is invariably more frequent in men and women of lower than higher socioeconomic status (SES). In spite of the overall decline in CHD rates, socioeconomic differences persist, and may even be widening, particularly in women. Most studies of SES and CHD have been done in men, and relatively little is known about the socioeconomic determinants of CHD risk in women. Studying SES and CHD in women is even more important than in men, because the attributable fraction of low SES for CVD, may be higher in women due to their more disadvantaged socioeconomic position.

Aims of the study: 1) To study the association between SES and CHD development in women, 2) To estimate the relative contribution of social and behavioral factors to the socioeconomic disparities in women's CHD, 3) To study the effects of SES and childhood circumstances on CHD prognosis in women, and 4) To study the associations between SES and physiological risk factors for CHD (obesity, atherogenic lipid profile and hemostatic dysfunction) in women.

Material and Methods: This is the first doctoral thesis which is based on data 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. To study the association between SES and CHD development, case-control analyses were done. To study the effects of SES and childhood circumstances on CHD prognosis, CHD patients were followed for 5-years after an acute event of CHD. Deaths from CHD, recurrent acute myocardial infarctions, and revascularizations were monitored. To study the associations between SES and physiological risk factors, cross-sectional analyses of the population-based healthy women (control-group) of the FemCorRisk Study were done.

Results: 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 (<9 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 explained the association between low education and increased CHD risk. Of these factors, psychosocial stress and unhealthy behaviors were the most important. Un/semiskilled 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, explained "only in part" why women with lower status jobs had an increased risk of CHD. The impact of low SES on a poorer prognosis of CHD, was unclear, but adverse childhood circumstances (as measured by short stature), showed a strong negative effect on CHD prognosis. In healthy women, low SES was associated with obesity, atherogenic lipid profile (mainly low HDL) and hemostatic dysfunction.

Conclusions: Findings in this thesis underline the importance of low SES in the etiology of CHD in women. The factors explaining the CHD-SES association in women range from adverse childhood circumstances, individual personality, social relations, health behaviors, biological risk factor profiles, to stressors that operate both at work and at home. 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.