Socioeconomic factors, body mass index and bariatric surgery: a Swedish nationwide cohort study

BACKGROUND: Bariatric surgery is considered to be the most effective method of weight loss today. The aim of the present Swedish study, which was performed in a country that has universal health care, was to investigate if there is an association between socioeconomic factors and bariatric surgery by taking body mass index (BMI) into account. METHODS: In this prospective cohort study, BMI data were collected for the period 1985–2010 from the Military Service Conscription Register (for men) and from the Medical Birth Register in the first trimester (for women). The follow-up period started in 2005 and continued until 2012. Age-standardized cumulative incidence rates (CR) of bariatric surgery were compared between different BMI groups by considering individual variables. We analyzed the association between the individual variables and bariatric surgery using Cox proportional hazard models. RESULTS: In the study population of 814,703 women and 787,027 men, a total of 7433 women and 1961 men underwent bariatric surgery. In women, the hazard ratios (HRs) for bariatric surgery were higher for low and middle income and educational levels, compared to high income and educational levels. In men, the highest HR for bariatric surgery was found among those with a high income. The HRs when comparing the different socioeconomic groups in those with BMI > 40 kg/m(2) showed no significant results, except for middle education in women. CONCLUSION: Differences in bariatric surgery between socioeconomic groups were found, favoring those with a low socioeconomic status. However, very few socioeconomic differences were found amongst those who had a BMI > 40 kg/m(2). This indicates that the Swedish healthcare system seems to have achieved equal access to health care for bariatric surgery. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12889-019-6585-8) contains supplementary material, which is available to authorized users.