Breastfeeding and the Risk of Childhood Hodgkin Lymphoma: A Systematic Review and Meta-analysis

Purpose: Numerous observational epidemiological studies have evaluated associations between breastfeeding and the risk of childhood Hodgkin lymphoma; however, the existing results are inconsistent. We therefore conducted a systematic review and meta-analysis. Methods: Medical literature was searched in the Pubmed and Embase databases to identify all English-language relevant studies up to April 10, 2013. Reference lists were thereafter hand-searched for additional articles. Studies that reported relative risk ratios (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were included. This meta-analysis was conducted in accordance with the guidelines for the meta-analysis of observational studies in epidemiology. Results: We finally included 10 case-control studies in our meta-analysis, involving 1,618 childhood Hodgkin lymphoma cases and 8,181 controls. Overall, we did found a borderline significant association between breastfeeding and reduced risk of childhood Hodgkin lymphoma comparing ever breastfed children to never breastfed children (pooled OR =0.79; 95% CI, 0.58-1.08; P=0.13), with limited evidence for between-study heterogeneity (P =0.12, I-2 =35.70%). Conclusion: There is limited evidence for an inverse association between breastfeeding and risk of childhood Hodgkin lymphoma.