Gender Differences in Socioeconomic Inequalities in Body Mass Index and Health-Related Mediators Among Young and Early Midlife Finns

Introduction: Socioeconomic differences in body mass index (BMI) are well established, but less is known about gender differences and their behavioral pathways. We examined gender differences in the association between socioeconomic position (SEP) and BMI, and whether dietary factors and physical activity mediated the associations. Methods: We used survey data from the employees of the City of Helsinki aged 19-39 collected in 2017 (n = 4,400, 80% women). SEP was measured by highest educational attainment, and the examined mediators were consumption of fruit and vegetables, red and processed meat, sweets and confectionery and alcohol as well as leisure-time vigorous physical activity (VPA) and sedentary time. We conducted gender-specific multiple mediation analyses using structural equation modeling and additional analyses using multiple imputation by chained equations. Results: With increasing educational attainment, mean BMI decreased from 26.4 kg/m2 to 24.0 kg/m2 among women, and from 26.6 kg/m2 to 25.2 kg/m2 among men. Lower SEP was associated with lower consumption of fruit and vegetables, higher consumption of red and processed meat, and lower VPA in both genders. Women reported healthier diets but less VPA than men. The strongest SEP-BMI mediator among women was VPA (indirect effect: 0.35, 95% confidence interval (CI) 0.26, 0.44), followed by fruit and vegetable consumption (0.15, 95% CI 0.08, 0.23) and red and processed meat consumption (0.06, 95% CI 0.02, 0.11). Among men, significant mediators were red and processed meat consumption (0.12, 95% CI 0.03, 0.23), sedentary time (0.11, 95% CI 0.01, 0.24) and VPA (0.10, 95% CI 0.02, 0.21). Conclusions: Socioeconomic inequalities in BMI appear stronger among women and are shaped through partly different mechanisms between genders. Improving VPA may be relevant among low-SEP women, whereas reducing sedentary time may be more relevant among low-SEP men. Reducing red and processed meat is beneficial for both genders.