Obesity and psychotropic medication: a prospective register linkage study among midlife women and men

BACKGROUND Both obesity and mental health are major public health issues. This study aimed to examine whether overweight and obesity among midlife employees are associated with subsequent psychotropic medication. A further aim was to examine the potential effect of key covariates on the association. METHODS The Helsinki Health Study baseline survey was conducted in 2000-2002 among 40-60-year-old employees of the City of Helsinki, Finland (n = 8960). The participants were classified as of normal weight (18.5-24.9 kg/m(2)), overweight (25-29.9 kg/m(2)), obese (30-34.9 kg/m(2)) or severely obese (≥35 kg/m(2)) based on self-reported body mass index. Data on psychotropic medication purchases from baseline to 2009 were derived from registers of the Social Insurance Institution of Finland. The final analysis included 4760 women and 1338 men. Antidepressants and sedatives were examined separately. Covariates included socio-demographic factors, workload, health behaviours, physical functioning, somatic ill-health and psychotropic medication prior to baseline. Hazard ratios (HR) for the first psychotropic medication purchase were calculated using Cox regression analysis. RESULTS Third of women and quarter of men made at least one psychotropic medication purchase during the follow-up. Adjusting for age, obese (HR = 1.57; 95 % CI = 1.10-2.24) and severely obese (HR = 2.15; 95 % CI = 1.29-3.56) men were at risk of having psychotropic medication compared to men of normal weight. These associations disappeared after further adjustment. Severe obesity remained associated with subsequent sedative medication among the men even after full adjustment (HR = 2.12; 95 % CI = 1.17-3.84). No associations were found among the women. CONCLUSIONS Obese and severely obese men, but not women, were at risk of psychotropic medication. Further studies are needed to deepen understanding of the relationship between obesity and mental ill-health, and the possible protecting effects of age, employment, and living environment.