TCF7L2 and type 2 diabetes mellitus: In fact, individuals with impaired glucose tolerance and undiagnosed diabetes at examination had the greatest protective effect on BMI of T2D-risk alleles at TCF7L2. Forthcoming HCHS/SOL, or other prospective cohort follow up data will allow future investigators to explore the contemporaneous and interacting relationships between TCF7L2, BMI and T2D status across the adult life course.