Population Trends in Exposure to Cigarette Smoke in the United States

摘要

The first national estimate of exposure of the U.S. population to secondhand smoke (SHS) based on serum cotinine (COT) measurements was obtained from samples collected in 1988-1991 as part of the Third National Health and Nutrition Examination Survey (NHANES Ⅲ). The data showed widespread exposure to nicotine: 88% of nonsmokers had measureable COT (≥0.050 ng/mL). In 1999 NHANES became a continuous biennial sampling of the U.S. population, and COT has been measured in each of the surveys since then. An early analysis of 1988-2002 NHANES data showed a significant decline of approximately 70% in COT concentrations in U.S. nonsmokers. For this presentation we analyzed all the NHANES COT data from 1988-2012 to examine recent population trends in exposure to nicotine. We calculated the geometric mean (GM) of COT concentrations in each survey period for all NHANES nonsmoker participants and by participant age, gender and race/ethnicity. We also calculated COT GMs of all nonsmoker participants for the time period 1999-2012 in order to investigate SHS exposure by age and by number of smokers in the home. All demographic groups of nonsmokers showed significant declines in the exposure to SHS over the 25 years of the surveys. Overall GM COT levels decreased 84% in nonsmokers: from 0.219 ng/mL in 1988-1991 to 0.035 ng/mL in 2011-2012. In contrast, mean COT levels in U.S. smokers did not change significantly during the same time period. In all age groups, mean nonsmoker exposure levels increased significantly with the number of smokers in the home. We also analyzed COT levels and other exposure biomarker results from NHANES participants. Our results indicate that tobacco smoke is a significant source of exposure for many environmental toxicants for both smokers and for nonsmokers with secondhand smoke exposure.