A cohort study of 52,731 women was carried out to examine the effect of childbearing and maternal breastfeeding on a woman's subsequent risk of developing type 2 diabetes. The researchers used information on parity, breastfeeding and diabetes and estimated the risk of type 2 diabetes using multivariate logistic regression. 3,160 (6.0%) women were classified with type 2 diabetes. Overall, nulliparous and parous women had a similar risk of diabetes. Among parous women, there was a 14% (p<0.001) reduced likelihood of diabetes per year of breastfeeding. Compared to nulliparous women, parous women who did not breastfeed had a greater risk of diabetes, (p<0.001); whilst for those breastfeeding for at least 3 months per child, the risk was not significantly increased. The authors conclude that compared to nulliparous women, childbearing women who do not breastfeed have about a 50% increased risk of type 2 diabetes in later life. Breastfeeding substantially reduces this excess risk.
Liu B, Jorm L, Banks E (2010) Parity, Breastfeeding and the Subsequent Risk of maternal Type 2 diabetes. Diabetes Care.