Socioeconomic differences in the progression of carotid atherosclerosis in middle-aged men and women with subclinical atherosclerosis in Sweden

Abstract

While the persistence of socioeconomic differences in cardiovascular disease (CVD) has been recognized for many years, less is known about whether socioeconomic factors are of importance to CVD before symptoms of the disease appear. In this study the associations among educational level, occupational status and progression of atherosclerosis were investigated in 1016 Swedish middle-aged men and women with signs of subclinical atherosclerosis, i.e., carotid plaque (defined as focal intima-media thickness (IMT) >1.2 mm). IMT in the common carotid artery (CCA) and in the carotid bifurcation area, as well as carotid plaque score, was determined by B-mode ultrasound. Results showed only weak associations between educational level, occupational status and age-, sex- and baseline IMT-adjusted progression of IMT in the CCA. However, in the age, sex- and baseline IMT-adjusted analyses, those in unskilled manual occupations showed a significantly higher yearly progression of carotid IMT in the bifurcation area compared to those in high- or medium-level non-manual occupations. Those with primary education tended to show a higher yearly progression of carotid IMT in the bifurcation area compared to those with completed secondary education. After adjustment for risk factors, the magnitude of these associations were somewhat attenuated. Similar patterns of associations were seen for the change of carotid plaque score. We conclude that low socioeconomic status (SES) is associated with progression of atherosclerosis in a middle-aged population with signs of subclinical atherosclerosis. Even though socioeconomic differences in cardiovascular risk factor levels could explain part of the found differences in progression rate in women, the mechanisms involved remain to be further established.