Breast-feeding and childhood-onset type 1 diabetes: a pooled analysis of individual participant data from 43 observational studies

OBJECTIVE-To investigate if there is a reduced risk of type 1 diabetes in children breastfed or exclusively breastfed by performing a pooled analysis with adjustment for recognized confounders. less thanbrgreater than less thanbrgreater thanRESEARCH DESIGN AND METHODS-Relevant studies were identified from literature searches using MEDLINE, Web of Science, and EMBASE. Authors of relevant studies were asked to provide individual participant data or conduct prespecified analyses. Meta-analysis techniques were used to combine odds ratios (ORs) and investigate heterogeneity between studies. less thanbrgreater than less thanbrgreater thanRESULTS-Data were available from 43 studies including 9,874 patients with type 1 diabetes. Overall, there was a reduction in the risk of diabetes after exclusive breast-feeding for andgt;2 weeks (20 studies; OR = 0.75, 95% CI 0.64-0.88), the association after exclusive breast-feeding for andgt;3 months was weaker (30 studies; OR = 0.87, 95% CI 0.75-1.00), and no association was observed after (nonexclusive) breast-feeding for andgt;2 weeks (28 studies; OR = 0.93, 95% CI 0.81-1.07) or andgt;3 months (29 studies; OR = 0.88, 95% CI 0.78-1.00). These associations were all subject to marked heterogeneity (I-2 = 58, 76, 54, and 68%, respectively). In studies with lower risk of bias, the reduced risk after exclusive breast-feeding for andgt;2 weeks remained (12 studies; OR = 0.86, 95% CI 0.75-0.99), and heterogeneity was reduced (I-2 = 0%). Adjustments for potential confounders altered these estimates very little. less thanbrgreater than less thanbrgreater thanCONCLUSIONS-The pooled analysis suggests weak protective associations between exclusive breast-feeding and type 1 diabetes risk. However, these findings are difficult to interpret because of the marked variation in effect and possible biases (particularly recall bias) inherent in the included studies. Funding Agencies|National Institutes of Health|R01-DK-46498R01-DK-42316|Chinese Foundation of Health||Department of Health, Executive Yuan, Republic of China|DOH91-TD1167|Ministry for Science and Technology of the Republic of Serbia|175042|German Research Foundation|HE 234/1-1|Research Council of Norway|148359/330