Longer term good quality studies found breastfeeding for >3 months decreased the risk of T2DM by >40% (HR 0.54, 95% CI 0.34–0.85) after adjusting for islet autoantibodies, family history of diabetes, maternal BMI, age, and smoking [103] and breastfeeding for >10 months improved glucose tolerance, and increased insulin sensitivity and insulin secretion/insulin sensitivity [104]. This evidence concerns the gene INS and diabetes mellitus.