Infant Feeding and Risk of Type 1 Diabetes in Two Large Scandinavian Birth Cohorts

Diabetes Care. 2017 Jul;40(7):920-927. doi: 10.2337/dc17-0016. Epub 2017 May 9.


Objective: Our aim was to study the relation between the duration of full and any breastfeeding and risk of type 1 diabetes.

Research design and methods: We included two population-based cohorts of children followed from birth (1996-2009) to 2014 (Denmark) or 2015 (Norway). We analyzed data from a total of 155,392 children participating in the Norwegian Mother and Child Cohort Study (MoBa) and the Danish National Birth Cohort (DNBC). Parents reported infant dietary practices when their child was 6 and 18 months old. The outcome was clinical type 1 diabetes, ascertained from nationwide childhood diabetes registries. Hazard ratios (HRs) were estimated using Cox regression.

Results: Type 1 diabetes was identified in 504 children during follow-up, and the incidence of type 1 diabetes per 100,000 person-years was 30.5 in the Norwegian cohort and 23.5 in the Danish cohort. Children who were never breastfed had a twofold increased risk of type 1 diabetes compared with those who were breastfed (HR 2.29 [95% CI 1.14-4.61] for no breastfeeding vs. any breastfeeding for ≥12 months). Among those who were breastfed, however, the incidence of type 1 diabetes was independent of duration of both full breastfeeding (HR per month 0.99 [95% CI 0.97-1.01]) and any breastfeeding (0.97 [0.92-1.03]).

Conclusions: Suggestive evidence supports the contention that breastfeeding reduces the risk of type 1 diabetes. Among those who were breastfed, however, no evidence indicated that prolonging full or any breastfeeding was associated with a reduced risk of type 1 diabetes.

MeSH terms

  • Adult
  • Breast Feeding*
  • Cohort Studies
  • Diabetes Mellitus, Type 1 / epidemiology*
  • Diabetes Mellitus, Type 1 / prevention & control
  • Diet
  • Female
  • Humans
  • Incidence
  • Infant
  • Male
  • Nutrition Assessment
  • Proportional Hazards Models
  • Registries
  • Risk Factors
  • Scandinavian and Nordic Countries / epidemiology
  • Socioeconomic Factors
  • Surveys and Questionnaires
  • White People*