TY - JOUR T1 - Effects of body mass index on relationship status, social contact, and socioeconomic position: Mendelian Randomization study in UK Biobank JF - bioRxiv DO - 10.1101/524488 SP - 524488 AU - Laura D Howe AU - Roshni Kanayalal AU - Robin N Beaumont AU - Alisha R Davies AU - Timothy M Frayling AU - Sean Harrison AU - Samuel E Jones AU - Franco Sassi AU - Andrew R Wood AU - Jessica Tyrrell Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/01/18/524488.abstract N2 - Objective To assess whether body mass index (BMI) has a causal effect on social and socioeconomic factors, including whether both high and low BMI can be detrimental.Design Mendelian Randomization, using genetic variants for BMI to obtain unconfounded estimates, and non-linear Mendelian Randomization.Setting UK Biobank.Participants 378,244 men and women of European ancestry, mean age 57 (SD 8 years).Main outcome measures Townsend deprivation index, income, age completed full time education, degree level education, job class, employment status, cohabiting relationship status, participation in leisure and social activities, visits from friends and family, and having someone to confide in.Results Higher BMI was causally associated with higher deprivation, lower income, fewer years of education, lower odds of degree-level education and skilled employment. For example, a 1 SD higher genetically-determined BMI (4.8kg/m2 in UK Biobank) was associated with £1,660 less income per annum [95%CI: £950, £2,380]. Non-linear Mendelian Randomization provided evidence that both low BMI (bottom decile, <22kg/m2) and high BMI (top seven deciles, >24.6kg/m2) can increase deprivation and reduce income. In men only, higher BMI was related to lower participation in leisure and social activities. There was no evidence of causal effects of BMI on visits from friends and family or in having someone to confide in. Non-linear Mendelian Randomization analysis showed that low BMI (bottom three deciles, <23.5kg/m2) reduces the odds of cohabiting with a partner or spouse for men, whereas high BMI (top two deciles, >30.7kg/m2) reduces the odds of cohabitation with a partner or spouse for women.Conclusions BMI affects social and socioeconomic outcomes, with both high and low BMI being detrimental for some measures of SEP. This suggests that in addition to health benefits, maintaining healthy ranges of BMI across the population could have benefits both for individuals and society. ER -