Beta-cell failure rather than insulin resistance is the major cause of abnormal glucose tolerance in Africans: insight from the Africans in America study. - Ishimwe MCS; Wentzel A; Shoup EM; Osei-Tutu NH; Hormenu T; Patterson AC; Bagheri H; DuBose CW; Mabundo LS; Ha J; Sherman A; Sumner AE (BMJ open diabetes research & care, 2021)