HLA-B^∗07, HLA-DRB1^∗07, HLA-DRB1^∗12, and HLA-c^∗03:02 strongly associate with BMI: Data from 1.3 million healthy Chinese adults

Strong associations between HLA alleles and infectious and autoimmune diseases are well established. Although obesity is also associated with these diseases, the relationship between HLA and obesity has not been systematically investigated in a large cohort. In the current study, we analyzed the association of HLA alleles with BMI using data from 1.3 million healthy adult donors from the Chinese Marrow Donor Program (CMDP). We found 23 HLA alleles, including 12 low-resolution and 11 highresolution alleles, were significantly associated with BMI after correction for multiple testing. Alleles associated with high BMI were enriched in haplotypes that were common in both Chinese and European populations, whereas the alleles associated with low BMI were enriched in haplotypes common only in Asians. Alleles B^∗07, DRB1^∗07, DRB1^∗12, and C^∗03:02 provided the strongest associations with BMI (P = 6.89 × 10^-10, 1.32 × 10^-9, 1.52 × 10^-9, and 4.45 × 10^-8, respectively), where B^∗07 and DRB1^∗07 also had evidence for sex-specific effects (P_{heterogeneity} = 0.0067 and 0.00058, respectively). These results, which identify associations between alleles of HLA-B, DRB1, and C with BMI in Chinese young adults, implicate a novelbiological connection between HLA alleles and obesity.