Although BMI is a well accepted and commonly used measure of obesity, it is an indirect and approximate measure of adiposity. BMI has two components, weight and height, and can also be influenced by lean and/or fat mass. To determine which aspect(s) of BMI are influenced by the variants we identified, we analyzed their association with the different anthropometric components of BMI, and also with a more direct measure of adiposity, percentage fat mass. All of the variants had much stronger associations with weight than with height (Supplementary Tables 6 and 8), with the exception that for KCTD15 and MTCH2 the small effects on BMI in stage 2 samples limited our ability to dissect the effect on BMI into its constituent components. Variation at MC4R was significantly associated with adult height, as previously reported9. To measure more directly the effects on adiposity, we tested these variants for association with percentage fat mass in a meta-analysis of three cohorts of adults in which percent fat mass was assessed (EPIC-Norfolk, Botnia PPP and METSIM; total n = 18,279), and also in the
