Educational Inequalities In Cardiovascular Disease

Educational inequalities in cardiovascular disease are evident in many countries, especially those in northern Europe. Cardiovascular disease also strongly contributes to overall health inequalities in these countries due to its relatively high prevalence. However, much less is known about biological mechanisms accounting for these inequalities. The metabolic syndrome is one potential factor behind educational and other socioeconomic inequalities in cardiovascular disease.

The metabolic syndrome is a metabolic state characterized by many classical risk factors of cardiovascular disease, i.e. abdominal obesity, low high-density lipoprotein (HDL) cholesterol, elevated triglycerides, hyperinsulinaemia, and hyperglycaemia. The causes of the metabolic syndrome are not yet well understood. In addition to behavioural factors, such as diet and physical activity, previous research indicates a strong genetic influence. It has also been suggested that undernutrition during fetal life and early childhood may cause permanent changes in human metabolism and thus affect the development of the metabolic syndrome in later life.6 Thus, the metabolic syndrome may mediate the effect of early material resources on later cardiovascular disease risk.

Inequalities in the prevalence of the metabolic syndrome by occupational status or education have been examined by three previous studies. In the Whitehall II Study with a large sample of British civil servants, a clear negative association was found between occupational status and the prevalence of the metabolic syndrome. Among men, the prevalence of the metabolic syndrome decreased across the six categories of the occupational scale, but among women a higher prevalence was found only in the three lowest categories. In a follow-up study in the UK, negative, but statistically insignificant, associations were found between the metabolic syndrome and socioeconomic class in childhood or in adulthood.

However, the sample size was smaller than in the Whitehall II study, which may explain the statistically insignificant results. In a study of Swedish women, an inverse gradient in the prevalence of the metabolic syndrome was found across categories of education.9 In this study, the age-adjusted prevalence of the metabolic syndrome was 2.6 times higher among women with basic education compared with women who had college or university level education. Adjustment for other risk factors only slightly decreased the occupational gradient in the Whitehall II study and the educational gradient in the Swedish study.

The social gradient in the metabolic syndrome could help explain socioeconomic inequalities in coronary heart disease (CHD). If so, then factors that cause the metabolic syndrome may also be important in the formation of social inequalities in CHD risk. Further, the metabolic syndrome may offer a simple screening tool to find sub-groups and individuals at high risk for CHD. If educational variation is found in the metabolic syndrome, then interventions to prevent and treat metabolic abnormalities, especially in people with low social position, may help to narrow socioeconomic inequalities in CHD. In this study, we examined educational disparities in the metabolic syndrome in a cohort of Finnish middle-aged men and women.

Education is a good indicator of social position in epidemiological studies because it precedes other indicators, such as occupational based social position or income, is comparable between men and women, does not usually change in adulthood, and shapes health behaviours through attitudes, values, and knowledge. First, we investigated whether there were educational differences in the prevalence of the metabolic syndrome and whether adjusting for other risk factors attenuated these differences. Second, we investigated whether the educational differences in the prevalence of the metabolic syndrome at baseline explained educational inequalities in CHD incidence.