Trends and variability in blood lead concentrations among US adults aged 20-64 years and senior citizens aged ≥65 years.

Using data from National Health and Nutrition Examination Survey for the period 2003-2012, the objective of this study was to evaluate trends in blood lead levels (BLL) among adults aged 20-64 years (adults) and seniors aged ≥65 years (seniors). In addition, the contribution of other factors like gender, race/ethnicity, smoking, and exposure to secondhand smoke at home in explaining variability in BLL was also evaluated by fitting regression models with log10 transformed values of BLL as dependent variables. BLL decreased over 2003-2012 (p < 0.01). Irrespective of gender, race/ethnicity, and smoking status, seniors were found to have higher BLL than adults. Based on the magnitude of differences between the 5th and 95th percentiles, variability in the levels of blood lead was found to be substantially higher among seniors than among adults. Males had statistically significantly higher adjusted BLL than females (2.32 vs. 1.76 μg/dL for seniors, p < 0.01 and 1.66 vs. 1.13 μg/dL for adults, p < 0.01). Non-Hispanic whites had statistically significantly lower adjusted BLL than non-Hispanic blacks (1.99 vs. 2.42 μg/dL for seniors, p < 0.01 and 1.22 vs. 1.42 μg/dL for adults, p < 0.01). When compared with non-smokers, smokers had statistically significantly higher BLL (2.19 vs. 1.86 μg/dL for seniors, p < 0.01 and 1.54 vs. 1.22 μg/dL for adults, p < 0.01). Non-obese had statistically significantly higher BLL than obese individuals (2.11 vs. 1.93 μg/dL for seniors, p < 0.01 and 1.48 vs. 1.27 μg/dL for adults, p < 0.01). Exposure to secondhand smoke at home (SHS) was associated with statistically significantly higher BLL than when there was no exposure to SHS (β = 0.0683, p = 0.03 for seniors; β = 0.034, p = 0.034, p < 0.01 for adults).