The role of preclinical atherosclerosis in the explanation of educational differences in incidence of coronary events

The associations between educational level, preclinical carotid atherosclerosis and incident coronary events (CE), were investigated in a general population sample of 5399 Swedish middle-aged men and women without history of cardiovascular disease (CVD) over a median follow-up of 8.7 years. Presence of carotid plaque (focal intima-media thickness (IMT) >1.2 mm) was determined by B-mode ultrasound. In the age- and sex-adjusted model, there was an inverse relationship between educational level and risk of future CE (p for trend = 0.002). To explore if there were education differences between groups with similar degrees of preclinical carotid atherosclerosis stratified analyses were made. Those with low educational level without carotid plaque showed a slightly increased hazard rate ratio (HRR), 1.14 (95% CI: 0.65, 1.97), compared to those with high educational level without carotid plaque (reference group). For those with high educational level with carotid plaque the HRR was 1.53 (95% CI: 0.92, 2.55). Having both low educational level and carotid plaque was associated with a HRR of 2.72 (95% CI: 1.72, 4.31). Individuals with plaque generally had more unfavourable cardiovascular risk factor levels, regardless of educational level. However, after risk factor adjustment those with both low education and carotid plaque still had a two-fold increased risk of CE. The results imply that differences in the prevalence of preclinical atherosclerosis seem important in explaining education differences in future coronary morbidity.