Breastfeeding duration in infancy and adult risks of type 2 diabetes in a high-income country

Matern Child Nutr. 2019 Oct;15(4):e12869. doi: 10.1111/mcn.12869. Epub 2019 Aug 2.


Observed associations between breastfeeding and reduced risk of type 2 diabetes in adulthood may be confounded. We examined if the duration of breastfeeding in infancy was associated with the risk of type 2 diabetes in adulthood after adjustment for a range of prenatal and postnatal risk factors. We prospectively followed 6,044 individuals from the Copenhagen Perinatal Cohort born 1959-1961. Duration of any breastfeeding (≤0.5, >0.5-1, >1-2, >2-4, >4 months) was assessed at the infant's 1-year health examination. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for type 2 diabetes (at age ≥30 years, 237 persons) by breastfeeding duration without and with adjustment for parental social status and education, maternal pre-pregnancy body mass index (BMI), maternal diabetes and smoking during pregnancy, gestational weight gain, parity, preterm birth, birth weight, sex, and BMI at ages 7 and 41-43 years. In the unadjusted analysis, compared with infants breastfed for ≤0.5 month, those breastfed for >4 months had a 51% reduced risk of type 2 diabetes (HR = 0.49; 95% CI [0.32, 0.75]). After the stepwise adjustment for putative early life confounders, this was attenuated to a nonsignificant 31% reduced risk (HR = 0.69; 95% CI [0.44, 1.07]). Adjustment for childhood and adulthood BMI minimally changed the results. We found that the inverse association between the duration of breastfeeding and risk of type 2 diabetes in adulthood is considerably weakened and no longer significant after adjustment for prenatal and postnatal factors in the infant and mother.

Keywords: breastfeeding; breastfeeding and diabetes; breastfeeding duration; cohort study; confounding variables; epidemiology; type 2 diabetes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Breast Feeding / statistics & numerical data*
  • Denmark / epidemiology
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Prospective Studies
  • Risk Factors
  • Time Factors
  • Young Adult