Incidence and prognosis of ischaemic heart disease with respect to marital status and social class. A national record linkage study.
Increased mortality from ischaemic heart disease (IHD) has been found in previous studies among divorced, widowed, and unskilled middle-aged Finnish men. In this study all cases of IHD in men aged 40-64 during 1972 were analysed by linking death certificates and hospital records (7499 cases with 3136 deaths). Age-adjusted incidence, mortality, and survival rates of the first and third year were calculated by marital status and social class. The highest mortality rate was found among unskilled workers, the highest incidence among widowers and those in the lower professional classes, and the lowest survival rate among divorcees, single persons, and unskilled workers. The ratio of mortality by marital status (1.77) was in part due to survival (ratio 1.44) and in part due to incidence (ratio 1.32). The ratio of mortality by social class (1.44) seemed to be due more to differences in incidence (ratio 1.36) than to differences in survival (ratio 1.18). The distribution of conventional risk factors of IHD by marital status and social class seems to explain only part of the mortality differences.