Social mobility and subclinical atherosclerosis in a middle-income country: Association of intra- and inter-generational social mobility with carotid intima-media thickness in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Abstract

Over the past half century Brazil has undergone a process of dramatic industrialization and urbanization. Cardiovascular diseases (CVD) have become common due to rapid demographic, epidemiologic, and nutritional transitions. The association of social mobility with subclinical CVD has been rarely explored, particularly in developing societies. We investigated the association of intra- and inter-generational social mobility with carotid intima-media thickness (IMT), a marker of subclinical or asymptomatic atherosclerosis, in a large Brazilian sample (ELSA-Brasil). We used baseline data (2008-2010) for 7343 participants from ELSA-Brasil. Intra-generational social mobility was defined as the change in occupational social class between participants' first occupation and current occupation. Inter-generational social mobility was defined as the change in occupational social class of the head of the household when the participant started working and participants' current occupation. Social mobility groups were classified as: stable high (reference), upward, downward and stable low. Linear regression models were used to examine the associations between type of social mobility and IMT. Compared to those who experienced stable high occupational status across generations, downward inter-generational mobility was associated with greater IMT. Additionally, those who declined the most in occupational status had the highest values of IMT, even after adjustments for lifestyle and cardiovascular factors. For intra-generational mobility, stable low versus stable high social mobility was independently associated with higher IMT. Subclinical atherosclerosis is patterned by socioeconomic status both within and across generations, demonstrating an association even before symptoms of CVD appear. The health consequences of downward inter-generational social mobility were not fully explained by lifestyle and cardiovascular factors, whereas being consistently exposed to low occupational status within one's own adulthood was associated with greater IMT, suggesting a cumulative risk model. Primary prevention of atherosclerosis should be complemented by macrosocial policies aimed to reduce downward socioeconomic mobility between generations.

Keywords: Brazil; Cardiovascular disease; Carotid intima-media thickness; Life course; Social mobility.