Quantifying the contributions of behavioral and biological risk factors to socioeconomic disparities in coronary heart disease incidence: the MORGEN study

Kiarri N. Kershaw, Mariël Droomers, Whitney R. Robinson, Mercedes R. Carnethon, Martha L. Daviglus, W. M. Monique Verschuren

Quantifying the impact of different modifiable behavioral and biological risk factors on socioeconomic disparities in coronary heart disease (CHD) may help inform targeted, population-specific strategies to reduce the unequal distribution of the disease. Previous studies have used analytic approaches that limit our ability to disentangle the relative contributions of these risk factors to CHD disparities. The goal of this study was to assess mediation of the effect of low education on incident CHD by multiple risk factors simultaneously. Analyses are based on 15,067 participants of the Dutch Monitoring Project on Risk Factors for Chronic Diseases aged 20-65 years examined 1994-1997 and followed for events until January 1, 2008. Path analysis was used to quantify and test mediation of the low education-CHD association by behavioral (current cigarette smoking, heavy alcohol use, poor diet, and physical inactivity) and biological (obesity, hypertension, diabetes, and hypercholesterolemia) risk factors. Behavioral and biological risk factors accounted for 56.6 % (95 % CI 42.6-70.8 %) of the low education-incident CHD association. Smoking was the strongest mediator, accounting for 27.3 % (95 % CI 17.7-37.4 %) of the association, followed by obesity (10.2 %; 95 % CI 4.5-16.1 %), physical inactivity (6.3 %; 95 % CI 2.7-10.0 %), and hypertension (5.3 %; 95 % CI: 2.8-8.0 %). In summary, in a Dutch cohort, the majority of the relationship between low education and incident CHD was mediated by traditional behavioral and biological risk factors. Addressing barriers to smoking cessation, blood pressure and weight management, and physical activity may be the most effective approaches to eliminating socioeconomic inequalities in CHD.