TG and type 2 diabetes mellitus: In a recent Mendelian randomization study of 69,033 euthyroid individuals with 12,171 cases of T2DM, no evidence for a causal relation was found between 20 genetic variants for TSH levels, and 4 variants for free thyroid hormone (fT4) levels, and insulin resistance and T2DM (Odds ratio 0.91 per SD TSH increase; 95% CI 0.78–1.07) [35].