The association between education and cardiovascular disease incidence is mediated by hypertension, diabetes, and body mass index

Irene R Dégano,Betlem Salvador-González,Alberto Zamora,Jaume Marrugat,Ruth Martí,Rafel Ramos,Maria Grau,Roberto Elosua

doi:10.1038/s41598-017-10775-3

Abstract

Education and cardiovascular disease (CVD) are inversely associated but the mediating factors have not been totally elucidated. Our aim was to analyze the mediating role of modifiable risk factors. Cohort study using the REGICOR population cohorts. Participants without previous CVD were included (n = 9226). Marginal structural models were used to analyze the association between education and CVD incidence at 6 years of follow-up. Mediation by modifiable risk factors (diabetes, dyslipidemia, hypertension, smoking, body mass index, and physical activity) was assessed using the counterfactual framework. Participants with a university degree had a CVD incidence hazard ratio (HR) of 0.51 (95% confidence interval (CI) = 0.30, 0.85), compared to those with primary or lower education. Only hypertension, BMI, and diabetes mediated the association between education and CVD incidence, accounting for 26% of the association (13.9, 6.9, and 5.2%, respectively). Sensitivity analyses showed that hypertension was the strongest mediator (average causal mediation effect [95% CI] = increase of 2170 days free of CVD events [711, 4520]). The association between education and CVD incidence is partially mediated by hypertension, BMI, and diabetes. Interventions to decrease the prevalence of these risk factors could contribute to diminish the CVD inequalities associated with educational level.

Highlights

There are a number of determinants that affect health
Our study showed an inverse association between education and cardiovascular disease (CVD) incidence in general population from North-Eastern Spain when comparing participants with university education to participants with primary or lower education
Further analyses showed that awareness, treatment, and control of diabetes and hypertension were not mediating the association between education and CVD incidence, and that hypertension was the strongest mediator

Summary

Introduction

There are a number of determinants that affect health. The World Health Organization has defined that determinants of health include the social and economic environment, the physical environment, and the individual characteristics and behaviors[1]. More recently some authors have examined the mediating role of modifiable classical cardiovascular risk factors (hypertension, diabetes, and dyslipidemia) and/or lifestyle factors (smoking, physical activity -PA-, body mass index -BMI-, and diet)[18,19,20] All these studies have shown evidence of the implication of both classical and lifestyle modifiable risk factors on the association between SES and CVD but their results were highly heterogeneous. These studies have not used new methodologies to estimate the effect of SES on CVD through a set of mediators and have not evaluated whether awareness, treatment, or control of classical risk factors is playing a role. The present study used a large population based cohort[21,22] to analyze the mediating role of modifiable risk factors on the association between education, as a SES indicator, and 6-year CVD incidence

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