Malki N, Koupil I, Eloranta S, Weibull CE, Tiikkaja S, Ingelsson E, Sparén P
PLoS ONE 9 (8) e105279 [2014-08-29; online 2014-08-29]
We analyzed temporal trends in the incidence of myocardial infarction and ischemic stroke in Sweden by socioeconomic position and investigated whether social inequalities in incidence of these diseases changed over time. We studied a cohort of almost three million Swedish residents born between 1932 and 1960 followed from 1987 until 2010. Incident cases of myocardial infarction and ischemic stroke were identified in the Swedish National Inpatient Register and Cause of Death Register. Socioeconomic position was retrieved from the Population and Housing Censuses. Incidence rates of myocardial infarction and ischemic stroke and incidence rate ratios comparing levels of socioeconomic position were estimated using flexible parametric survival models adjusted for calendar year, attained age, sex, and birth country. The overall incidences of myocardial infarction and ischemic stroke decreased over time among men, but were stable over time among women. With regard to ischemic stroke incidence, socioeconomic inequality increased over time in the age group 55 to 59: the incidence rate ratios for low manual compared to high non-manual increased from 1.3 (95% CI: 1.2-1.4) in 1997 to 1.5 (1.4-1.7) in 2010 among men, and from 1.4 (1.3-1.6) in 1997 to 2.1 (1.8-2.5) in 2010 among women. The socioeconomic inequality in incidence of myocardial infarction was stable over time for both men and women. There was a decrease in myocardial infarction and ischemic stroke incidence over time among men but no significant change for women. Our study highlights existing, and in some cases increasing, social inequalities in the incidence of cardiovascular diseases.