Association of environmental toxicants and conduct disorder in U.S. children: NHANES 2001-2004

Abstract

Objective: The purpose of this study was to examine the association of tobacco smoke and environmental lead exposure with conduct disorder (CD).

Methods: The National Health and Nutrition Examination Survey (NHANES) 2001-2004 is a nationally representative cross-sectional sample of the noninstitutionalized U.S. population. We examined the association of prenatal tobacco, postnatal tobacco, and environmental lead exposure with CD in children 8-15 years of age (n = 3,081). We measured prenatal tobacco exposure by parent report of cigarette use during pregnancy, and postnatal tobacco using serum cotinine levels. We assessed lead exposure using current blood lead concentration. Parents completed the Diagnostic Interview Schedule for Children to determine whether their children met criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV ) for CD.

Results: Overall, 2.06% of children met DSM-IV criteria for CD in the past year, equivalent to 560,000 U.S. children 8-15 years of age. After adjustment, prenatal tobacco exposure was associated with increased odds for CD [odds ratio (OR) = 3.00; 95% confidence interval (CI), 1.36-6.63]. Increased blood lead levels (fourth vs. first quartile) and serum cotinine levels (fifth vs. first quintile) were associated with an 8.64-fold (95% CI, 1.87-40.04) and 9.15-fold (95% CI, 1.47-6.90) increased odds of meeting DSM-IV CD criteria. Increasing serum cotinine levels and blood lead levels were also associated with increased prevalence of CD symptoms (symptom count ratio, lead: 1.73; 95% CI, 1.23-2.43; symptom count ratio, cotinine: 1.97; 95% CI, 1.15-3.40).

Conclusions: These results suggest that prenatal tobacco exposure and environmental lead exposure contribute substantially to CD in U.S. children.

Keywords: NHANES; conduct disorder; cotinine; epidemiology; lead poisoning; tobacco smoke.

Figure 1

Adjusted mean symptom CD symptom counts by serum cotinine quintile among children without prenatal tobacco smoke exposure, adjusted for child’s age in years, PIR, maternal age at child’s birth, child’s sex, child’s race, prenatal tobacco smoke exposure, and cotinine levels. The mean symptom count is derived from the Poisson regression models presented in Table 4. Error bars represent 95% CIs.