Islet Autoimmunity Risk Not Affected by Infant Formula Type

Infant formula type does not appear to affect the risk for islet autoimmunity.
Infant formula type does not appear to affect the risk for islet autoimmunity.

Consumption of hydrolyzed vs nonhydrolyzed cow's milk-based infant formula does not decrease, and may even increase, risk for islet autoimmunity in children who are at an increased genetic risk for type 1 diabetes, researchers reported in Diabetes Care.

“Although the evidence for an association between early cow's milk exposure or longer exclusive breast-feeding duration and type 1 diabetes risk is limited, various infant feeding policies suggest a type 1 diabetes protective effect by delayed introduction of cow's milk,” they wrote. “As a result, healthcare professionals and mothers are uncertain regarding the choice of infant formula if breast-feeding is not possible or additional milk feeding is needed.”

In the TEDDY (The Environmental Determinants of Diabetes in the Young; ClinicalTrials.gov identifier: NCT00279318) study, the researchers examined the environmental causes of type 1 diabetes in a prospective cohort of children who have an increased genetic risk for the disease. A total of 8676 children recruited at 6 clinical research centers — 3 in the United States and 3 in Europe — were included in the study. The researchers measured autoantibodies to insulin, GAD65, and IA2 to define islet autoimmunity and collected information about formula feeding via questionnaires at age 3 months. Median follow-up was 8 years.

After adjustment for family history of type 1 diabetes, HLA genotype, sex, country, delivery mode, breast-feeding for at least 3 months, and seasonality of birth, survival analyses demonstrated no significant association between islet autoimmunity and consumption of hydrolyzed vs nonhydrolyzed infant formula as first formula during the first 3 months of life (adjusted hazard ratio [HR]: 1.38; 95% CI, 0.95-2.01). However, risk for islet autoimmunity was increased with the introduction of hydrolyzed formula during the first 7 days of life (adjusted HR: 1.57; 95% CI, 1.04-2.38).

No formula or use of a partially hydrolyzed or other type of formula as first formula were also not associated with risk for islet autoimmunity.

“Our study provides further evidence that there is no benefit for infants at increased genetic risk for type 1 diabetes to be fed extensively or partially hydrolyzed infant formula as a first formula if breast-feeding is not possible,” the researchers concluded. “For infants who cannot be breast-fed, hydrolyzed infant formula should therefore be considered in the context of atopy prevention, according to recommendations published by pediatric authorities.”

Study Limitations

  • The follow-up time covers early islet autoimmunity, but longer follow-up would be required to investigate whether infant formula feeding is associated with progression to clinical type 1 diabetes.
  • Most infants fed hydrolyzed formula were from Finland (80.5%).
  • The researchers lacked information on why parents chose a certain formula type.
  • Other unmeasured variables cannot be excluded as confounders.
  • Because the study population was selected based on HLA genotype, results may not be generalizable.

Reference

  1. Hummel S, Beyerlein A, Tamura R, et al; for the TEDDY Study Group. First infant formula type and risk of islet autoimmunity in The Environmental Determinants of Diabetes in the Young (TEDDY) study [published online January 17, 2017]. Diabetes Care. doi: 10.2337/dc16-1624
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