Multiple environmental chemical exposures to lead, mercury and polychlorinated biphenyls among childbearing-aged women (NHANES 1999-2004)

Purpose. Lead, mercury and polychlorinated biphenyls (PCBs) are neurotoxicants with intergenerational health consequences from maternal body burden and gestational exposures. Little is known about multiple chemical exposures among childbearing-aged women. Research Questions. 1. What is the percentage of childbearing-aged women who have all three xenobiotics at or above the median in their blood/serum? 2.What is the most common binary chemical combination based on body burden? 3. Which women were disproportionately burdened based on vulnerability factors? Methodology. This descriptive and exploratory study involved analysis of existing data from the National Health and Nutrition Examination Survey (NHANES), a national probability sample. The outcome of interest was based on evidence of the biological uptake of lead and mercury in blood and PCBs in serum of these women aged 16 to 49 of diverse races and ethnicities who were living in the U.S. 1999 to 2004. The scientific literature guided the selection of 62 measures of vulnerability (susceptibility- and exposure-related attributes, socioeconomic factors and race-ethnicity). Results. More than one fifth of childbearing-aged women had all three xenobiotic levels at or above the median. Lead-PCBs was the most common binary chemical combination. The best-fit logistic regression model without interactions contained 12 variables (R²=.28). Four risk factors were notable (P<.05). An exponential relationship was demonstrated with increasing age. Any fish consumption in past 30 days more than doubled the odds. Heavy alcohol consumption or binge drinking increased risk. A history of breastfeeding children lowered their risk as did occasional alcohol consumption. Conclusions. These findings are the first description of multiple chemical exposures among U.S. childbearing-aged women. This study further supports increasing age, fish consumption and heavy alcohol consumption as significant risk factors. Prior history of breastfeeding lowered their risk. Some evidence was found of increased body burden among minority women but this relationship was not stable.