Associations between blood lead level and substance use and sexually transmitted infection risk among adults in the United States.

The effects of low-level lead exposure on neuropsychological status in the United States (US) general adult population have been reported, and the relationship between neuropsychiatric dysfunction and health risk behaviors including substance use and sexual risk taking is well established. However, the potential influence of lead exposure on risk-taking behavior has received little attention. Using the National Health and Nutrition Examination Survey (NHANES) 2005-2010, we estimated multivariable logistic regression models to measure odds ratios (ORs) and 95% confidence intervals (CIs) for the cross-sectional associations between blood lead level and risk behaviors including binge drinking, drug use, and indicator of sexually transmitted infection (STI) risk. STI indicators included past 12 month sexual risk behaviors (age mixing with partners who were at least five years younger or older and multiple partnerships), self-reported STI, and biologically-confirmed herpes simplex virus type 2 (HSV-2) infection. Dose-response like relationships were observed between blood lead and substance use, age mixing with younger and older partners, self-reported STI, and HSV-2. In addition, participants with lead levels in highest quartile versus those with levels in the lowest quartile had over three times the odds of binge drinking and over twice the odds of injection drug or cocaine use in the past 12 months, while being in one of the top two quartiles was significantly associated with 30-70% increased odds of multiple partnerships, sex with older partners, and self-reported and biologically confirmed STI. Results from this study suggested that lead exposure may contribute to substance use, sexual risk-taking, and STI. However, given limitations inherent in the cross-sectional nature of the study, additional studies that use longitudinal data and measure detailed temporal information are warranted.