Objective To measure polybrominated diphenyl ethers (PBDEs) concentrations in cord blood of newborns in Minhang District of Shanghai and explore risk factors of PBDEs exposure.
Methods The present study was based on the Shanghai Minhang Birth Cohort Study (S-MBCS)from April to December of 2012. We analyzed the concentrations of nine congeners of PBDEs (BDE-28, BDE-47, BDE-66, BDE-85, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) in cord blood samples (n=340). A questionnaire survey was conducted to understand the basic demographic characteristics, pregnancy condition, lifestyle, early pregnancy dietary intake, and disease history of enrolled pregnant women. Multiple linear regression model was used to compare PBDEs concentrations in cord blood of newborns across maternal demographic characteristics, lifestyles, and dietary factors, taking the concentration of PBDEs after logarithmic transformation as the dependent variable and the value of b after exponential transformation as the change of the ratio of geometric mean (GM) of PBDEs concentration over each unit change of a specific independent variable.
Results At least one PBDEs congener was detected among 98.82% of the subjects. Among the nine congeners, BDE-47 had the highest detection rate (83.82%), followed by BDE-28 (62.65%) and BDE-99 (61.76%); BDE-100 and BDE-153 were detected in nearly half of the samples (49.71% and 48.53%); while the detection rates of BDE-66, BDE-85, BDE-154, and BDE-183 ranged from 18.53% to 26.47%. The median concentrations were 0.67 ng/g (in terms of per gram of lipid, thereafter) for Σ9 PBDEs (the sum of nine BDE congeners) and 0.38 ng/g for Σ4 PBDEs (the sum of four penta-BDEs:BDE-47, BDE-99, BDE-100, and BDE-153). BDE-47 was also the predominant PBDE with highest median concentration (0.19 ng/g), followed by BDE-99 (0.07 ng/g) and BDE-28 (0.05 ng/g). The results of multiple linear regression analysis showed that newborns with >29-year-old mothers had higher BDE-47 and Σ4 PBDEs levels than those with < 25-year-old mothers (GM ratio=1.82, 95%CI:1.10-3.03; GM ratio=1.51, 95%CI:1.01-2.26); newborns whose mothers with high school or technical secondary school education had higher BDE-47 (GM ratio=2.44, 95%CI:1.23-4.87) and Σ4 PBDEs levels (GM ratio=1.74, 95%CI:1.00-3.02) than those whose mothers with middle school or lower education; newborns with multiparous mothers had a higher Σ9 PBDEs level than those with nulliparous mothers (GM ratio=1.48, 95%CI:1.01-2.17); newborns born to mothers with weight gain >10 kg during pregnancy had a higher concentration of BDE-47 than those mothers with weigh gain of 5-10 kg (GM ratio=1.63, 95%CI:1.15-2.33). The results for the other factors were not statistically significant.
Conclusion Nine PBDEs congeners are detected in cord blood of newborns in the present study. Mothers who are older, well educated, multiparous, or have lower weight gain during pregnancy may have newborns with higher cord blood PBDEs concentrations.
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