The IVW method showed that lower birth weight was associated with a higher risk of T2DM (β: −1.113, 95% CI: −1.573 ∼ −0.652), higher fasting insulin (β: −0.080, −0.108 ∼ −0.052) and higher two-hour glucose (β: −0.250, −0.360 ∼ −0.140). The gene discussed is INS; the disease is type 2 diabetes mellitus.