We perform multivariable cis-Mendelian randomization for variants in the GLP1R gene region: first, considering body mass index (BMI) and type 2 diabetes (T2D) as distinct risk factors, representing two outcomes affected by GLP1R agonism; and second, considering GLP1R gene expression in different tissues as risk factors. Here, GLP1R is linked to type 2 diabetes mellitus.