GK and type 2 diabetes mellitus: Genetically-proxied impaired GK-GKRP interaction was associated with reduced risk of T2D (odds ratio [OR] 0.09 per 1 mmol/L lower FPG, 95% confidence interval [CI] 0.03–0.28, P = 2.53 × 10−5) and did not influence plasma insulin level (β − 1.43 per 1 mmol/L lower FPG, 95% CI − 3.19 to 0.33, P = 0.111) (Tables 1 and 2).