SOCIOECONOMIC DIFFERENCES IN RISK OF MYOCARDIAL-INFARCTION 1971-1994 IN SWEDEN - TIME TRENDS, RELATIVE RISKS AND POPULATION ATTRIBUTABLE RISKS

Background The general trend in incidence of myocardial infarction (MI ) in the Stockholm area changed from increasing to decreasing around 1 980. The objective of this study is to examine time trends in incidenc e in major socioeconomic strata, relative risk between socioeconomic g roups and population risk attributable to socioeconomic differences du ring this period. Methods All cases of MI from 1971 to 1986 were ident ified from hospital discharge and cause-of-death registers. Person-yea rs for each year of follow-up were calculated from the population regi ster in the Stockholm region 1971-1986. Census registers were used for information on socioeconomic status. Register information was individ ually linked through the Swedish personal identification number, Suppl ementary information for 1992-1994 was taken from the case-control stu dy SHEEP (Stockholm Heart Epidemiology Program). Results The decline i n MI risk among male high- and middle-level employees started in 1976 and in male manual workers in 1981. For women incidence inn-eased from 1971 to 1986 among manual workers and decreased among high- and middl e-level employees. The increase over time of the relative risk from lo w socioeconomic position continued into the 1990s. Despite the reducti on of the category of manual workers, the population attributable risk from socioeconomic differences also increased over time. The process of social change influencing the size of the socioeconomic groups cont ributes to the change in time trends of MI morbidity. Conclusions The increase over time of relative and population attributable risks of MI from low socioeconomic status add to the public health importance of social inequity.