Relationship between occupational social class and exposure to organochlorine pesticides during pregnancy

Background: Little evidence is available on the influence of socioeconomic factors on exposure to persistent organic pollutants, especially during vulnerable periods such as pregnancy and early life.

Objective: To investigate the relationship of maternal social class with placental concentrations of organochlorine pesticides (OCPs) and their combined estrogenic activity measured with a biomarker of exposure.

Methods: Exposure to 16 OCPs (DDTs, endosulfans, and seven other compounds) and the total effective xenoestrogenic burden (TEXB) were analyzed in placentas from a mother-child cohort. OCP concentrations were quantified by gas chromatography and mass spectrometry, and TEXB was assessed with the E-Screen bioassay. Social class was classified according to maternal occupation. Multivariate regression analysis was conducted to examine variations in pesticide exposure and TEXB as a function of maternal social class in 257 subjects.

Results: Placental p,p'-DDT concentrations were higher in social classes III and IV than in classes I-II (the most affluent); concentrations of the sum of DDTs were higher in class IV; and exposure to the sum of endosulfans was greater in class III. HCB concentrations were higher among women in class IV than in classes I-II and among manual (classes III-V) than non-manual workers. However, the trend across social classes was only statistically significant for HCB. Social class significantly explained 10% of the variability in concentrations of the sum of endosulfans.

Conclusion: There is a need to explore whether more disadvantaged populations suffer higher levels of exposure to pesticides or other environmental chemicals and how different social processes contribute to this exposure.