Temporal Trends of Secondhand Smoke Exposure: Nonsmoking Workers in the United States (NHANES 2001-2010)

BACKGROUND: The workplace is one of the major locations outside of the home for nonsmokers' exposure to secondhand smoke (SHS). New policies in many U.S. states and localities restrict or prohibit smoking in the workplace, and information on current trends in the exposure of nonsmokers to SHS across various occupational groups is therefore needed. OBJECTIVE: We evaluated temporal trends in SHS exposure among nonsmoking workers in the United States and identified those occupations with workers with the highest levels of SHS exposure. METHODS: We combined serum cotinine (sCOT) measurements and questionnaire data from five survey cycles of the National Health and Nutrition Examination Survey (NHANES: 2001-2010). Trends in SHS exposure by occupations were determined from percent changes and least-squares geometric means (LSGMs) of sCOT concentrations computed using sample-weighted multiple regression models. RESULTS: Between NHANES 2001-2002 and NHANES 2009-2010, LSGMs of sCOT levels had changed -25% (95% CI: -39, -7%) in nonsmoking workers. The largest decrease was identified among food preparation workers [-54% (95% CI: -74, -19%)], followed by white-collar [-40%, (95% CI: -56, -19%)] and blue-collar workers (-32%, 95% CI: -51, -5%). LSGMs of sCOT remained highest in food preparation workers in all survey cycles, but the gap between occupations narrowed in the latest survey cycle (2009-2010). For example, the gap in LSGMs of sCOT between food preparation and science/education workers dropped > 70% during 2000 to 2010. CONCLUSIONS: During the period from 2001 to 2010, the overall SHS exposure in nonsmoking workers declined with substantial drops in food preparation/service and blue-collar workers. Although disparities persist in SHS exposure, the gaps among occupations have narrowed.