A previously reported T2D locus (TCF7L2) was associated with both using second-line T2D treatments (Pmeta = 2.1 × 10−13) and insulin (Pmeta = 2.3 × 10−11) (one CS per analysis) (Extended Data Fig. 5h,i and Supplementary Tables 12 and, 17). Here, TCF7L2 is linked to type 2 diabetes mellitus.