Global, multi-ethnic genome-wide association meta-analysis of body mass index: A.E. Locke 1; S. Vedantam 2,3; E. Marouli 4; S. Berndt 5; L. Yengo 6; A.R. Wood 7; T. Ferreira 8; S. Graham 9; on behalf of the Genetic Investigation of ANthropometric Traits (GIANT) Consortium