BackgroundAnalyses of mortality data for participants examined in 1976–1980 in the second National Health and Nutrition Examination Survey (NHANES II) suggested an increased risk of mortality at blood lead levels > 20 μg/dL. Blood lead levels have decreased markedly since the late 1970s. In NHANES III, conducted during 1988–1994, few adults had levels > 20 μg/dL.ObjectiveOur objective in this study was to determine the risk of mortality in relation to lower blood lead levels observed for adult participants of NHANES III.MethodsWe analyzed mortality information for 9,757 participants who had a blood lead measurement and who were ≥ 40 years of age at the baseline examination. Using blood lead levels categorized as < 5, 5 to < 10, and ≥ 10 μg/dL, we determined the relative risk of mortality from all causes, cancer, and cardiovascular disease through Cox proportional hazard regression analysis.ResultsUsing blood lead levels < 5 μg/dL as the referent, we determined that the relative risk of mortality from all causes was 1.24 [95% confidence interval (CI), 1.05–1.48] for those with blood levels of 5–9 μg/dL and 1.59 (95% CI, 1.28–1.98) for those with blood levels ≥ 10 μg/dL (p for trend < 0.001). The magnitude of risk was similar for deaths due to cardiovascular disease and cancer, and tests for trend were statistically significant (p < 0.01) for both causes of death.ConclusionIn a nationally representative sample of the U.S. population, blood lead levels as low as 5–9 μg/dL were associated with an increased risk of death from all causes, cardiovascular disease, and cancer.

Exposure to methyl mercury, a risk factor for neurodevelopmental toxicity, was assessed in U.S. Hair mercury levels were associated with age and fish consumption frequency.

We report population-based concentrations, stratified by age, sex, and racial/ethnic groups, of dialkyl phosphate (DAP) metabolites of multiple organophosphorus pesticides. We measured dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate (DEP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP) concentrations in 1,949 urine samples collected in U.S. residents 6-59 years of age during 1999 and 2000 as a part of the ongoing National Health and Nutrition Examination Survey (NHANES). We detected each DAP metabolite in more than 50% of the samples, with DEP being detected most frequently (71%) at a limit of detection of 0.2 microg/L. The geometric means for the metabolites detected in more than 60% of the samples were 1.85 microg/L for DMTP and 1.04 microg/L for DEP. The 95th percentiles for each metabolite were DMP, 13 microg/L; DMTP, 46 microg/L; DMDTP, 19 micro g/L; DEP, 13 microg/L; DETP, 2.2 microg/L; and DEDTP, 0.87 microg/L. We determined the molar sums of the dimethyl-containing and diethyl-containing metabolites; their geometric mean concentrations were 49.4 and 10.5 nmol/L, respectively, and their 95th percentiles were 583 and 108 nmol/L, respectively. These data are also presented as creatinine-adjusted concentrations. Multivariate analyses showed concentrations of DAPs in children 6-11 years of age that were consistently significantly higher than in adults and often higher than in adolescents. Although the concentrations between sexes and among racial/ethnic groups varied, no significant differences were observed. These data will be important in evaluating the impact of organophosphorus pesticide exposure in the U.S. population and the effectiveness of regulatory actions.