Predictors of environmental lead exposure among pregnant women – a prospective cohort study in Poland

Blood lead levels (BLL) in women of child-bearing age have been decreasing in recent decades, but still remains a concern for long-term effects of child psychomotor development. The aim of the study was to characterize lead exposure among Polish pregnant women and assess the relationship between BLL and selected socio-demographic, economic and lifestyle factors. The study population consisted of 594 pregnant women who had been the subjects of the prospective Polish Mother and Child Cohort Study (REPRO_PL). The women were interviewed three times during pregnancy (once in each trimester. Lead concentration in the blood collected during the second trimester of pregnancy was analyzed using graphite furnace atomic absorption spectrometry (GF-AAS), or inductively coupled plasma mass spectrometry (ICP-MS). Active and passive smoking was analyzed by the cotinine level in saliva using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The lead level in the blood ranged from 0.3 – 5.7 μg/dL, with a geometric mean (GM) of 1.1 μg/dL (GSD }0.2 μg/dL). Statistically significant associations were found between BLL and factors such as maternal age (β=0.01; p=0.02), education (β=0.08; p=0.04) and prepregnancy BMI (β=0.1; p=0.001). Additionally, BLL increased with increasing cotinine level in saliva (β=0.02; p=0.06) and decreased with the increasing distance from the copper smelter (β=-0.1; p=0.009). Public health interventions, especially in regions with a higher level of exposure to lead, among women with lower SES and among smokers, are still reasonable.