Education and hypertension in the CONSTANCES cohort: which factors mediate this association?
Résumé
BackgroundIndividual socioeconomic characteristics and in particular education have been shown to be strongly associated with hypertension (HTN). Few studies have examined the mechanisms involved in such associations and understanding them would help to reduce the burden of social inequalities. We aimed to investigate whether specific risk factors of HTN intervene as mediators in the association between individual education and HTN in a large sample of French adults.MethodsIn this cross-sectional analysis, participants are adults aged between 18 and 69 years old recruited to the CONSTANCES cohort over the period 2012-2015. We included behavioral (poor diet, physical inactivity, alcohol consumption), anthropometric (body mass index) and socioeconomic risk factors (income and longest occupation) as potential mediators. Analyses were stratified by sex. Natural direct and indirect effects of education on HTN were estimated using weighted Poisson regression models with inverse odds weighting.ResultsA total of 62,247 individuals (53% women, mean age 48±13 years) were included. Prevalence of HTN was 37.3% [95%-Confidence Interval (95%-CI) =36.6-38.0] in men and 23.2% [95%-CI=22.7-23.8] in women. We found a steep educational gradient of HTN in both sexes, larger among young adults in relative terms. Low education was strongly associated with HTN: RRTotal Effect=1.16 [95%-CI=1.12-1.21] in men and 1.26 [95%-CI=1.21-1.32] in women. Behavioral, anthropometric and socioeconomic risk factors accounted for 49% and 32% of the total effect in men and women respectively.ConclusionsThis study underlines the importance of education in inequalities in HTN and suggests that behavioral, anthropometric and socioeconomic risk factors substantially mediate the association between education and HTN. Future research using longitudinal data should be done to help understand the causal pathway linking education and HTN.