Polybrominated Diphenyl Ether Concentrations in Human Breast Milk Specimens Worldwide

Background: Polybrominated diphenyl ethers (PBDEs) are a class of flame retardants of ubiquitous presence in numerous consumer products. PBDEs may impair neurodevelopment in infants. There is a lack of meta-analysis on PBDE concentrations in human breast milk worldwide. We aimed to summarize global research data on PBDE concentrations in human breast milk specimens in recent years. Methods: We conducted a systematic review through PubMed search of original studies on PBDE concentrations in human individual breast milk specimens collected in the general population over the recent 15-year period (2000-2015) worldwide. Results: A total of 49 eligible studies (total number of study subjects = 7,502) were identified. The pooled means (95% CI) of total PBDE concentration in breast milk (ng/g lipid) were 66.8 (44.7, 88.9) in North America, 2.6 (2.2, 3.1) in Europe, and 2.8 (2.4, 3.3) in Asia, respectively. The pooled means (95% CI) of median total PBDEs concentration in breast milk (ng/g lipid) were 40.0 (30.8-49.1) in North America, 1.9 (1.4-2.4) in Europe, and 2.2 (1.3-3.2) in Asia. The high concentrations of total PBDEs in breast milk in North America were mainly due to high concentrations of brominated diphenyl ether-47 (BDE-47), BDE-99, BDE-100, and BDE-153. There were too few studies from other continents (Africa, South America, and Oceania) for meaningful meta-analysis. Conclusion: Total PBDE concentrations in breast milk in the recent 15-year period were over 20 times higher in North America versus Asia or Europe, and comparable in Europe versus Asia. There is a need for more research data from other continents.