LAUSR

AIMS Obesity levels have increased worldwide with serious public health concerns. However, weight status is related to socioeconomic status (SES), which may also influence health-related lifestyles. Here we study the association between SES and obesity mediated by diet and physical activity. METHOD AND RESULTS Using cross-sectional data from 2006, 2011, 2014 and 2017 Spanish health surveys (final sample consisted of 61,768 adults aged between 18 and 64), we conducted a latent class analysis to estimate health-related lifestyle clusters (based on dietary patterns and physical activity) and mediation analyses to evaluate the association of SES and obesity through the clustering of health-related lifestyles. In both men and women, SES was inversely related to obesity (p < 0.001) and positively related to healthier lifestyle classes (p < 0.001). Obesity was inversely related to healthier lifestyle classes (p < 0.001). A small -although significant- proportion mediated by the clustering of lifestyles was found: 4.9%, 95% CI (6.6%, 3.2%) in men and 2.3%, 95% CI (3.4%, 1.3%) in women for educational attainment, 5.3%, 95% CI (7.2%, 3.6%) in men and 2.0%, 95% CI (2.9%, 1.1%) in women for occupational social class, and 4.9%, 95% CI (6.5%, 3.1%) and 1.9%, 95% CI (2.9%, 1.1%) combining the above two SES indicators. CONCLUSIONS SES is related to obesity through the clustering of health-related lifestyles, with greater emphasis on men. However, the complex relationship between SES and weight status also suggests other indicators that contribute to the social gradient of obesity.