Secondhand smoke exposure among nonsmokers nationally and in New York City

We describe smoking prevalence and secondhand smoke (SHS) exposure among adult nonsmokers in New York City (NYC) across key demographic strata and compare exposure estimates with those found nationally. We used serum cotinine data from the 2004 NYC Health and Nutrition Examination Survey (n = 1,767 adults aged 20 years or older) and the 2003-2004 National Health and Nutrition Examination Survey (n = 4,476 adults aged 20 years or older) to assess and compare smoking prevalence and the prevalence of elevated cotinine levels (>= 0.05 ng/ml) among nonsmokers. We conducted multivariate logistic regression to assess independent predictors of elevated cotinine levels in NYC. Although the smoking prevalence in NYC was lower than that found nationally (23.3% vs. 29.7%, p < .05), the proportion of nonsmoking adults in NYC with elevated cotinine levels was greater than the national average overall (56.7% vs. 44.9%, p < .05) and was higher for most demographic subgroups. In NYC, the highest cotinine levels among nonsmokers were among adults aged 20-39 years, males, and Asians. Although NYC enacted comprehensive smoke-free workplace legislation in 2003, findings suggest that exposure to SHS remains a significant public health issue, especially among certain subgroups. The finding of a higher prevalence of SHS exposure in NYC despite lower smoking rates is puzzling but suggests that SHS exposure in dense, urban settings may pose a particular challenge.