General exposure to secondhand smoke (SHS) has decreased by half since 1999–2000 but 58 million Americans were still exposed to SHS during 2011–2012, according to the Centers for Disease control and Prevention (CDC)’s Morbidity and Mortality Weekly Report (MMWR).

Data from the National Health and Nutrition Examination Survey (NHANES) during 1999–2012 was studied for exposure to SHS among nonsmokers aged ≥3 years. SHS exposure was defined as a serum cotinine level of 0.05–10ng/mL. Assessment by age, sex, race/ethnicity, poverty level, education, and homeowner vs. rental status was included as well as overall SHS exposure.

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Study analysis found that SHS exposure in nonsmokers was down from 52.5% in 1999–2000 to 25.3% during 2011–2012. The overall decline was seen in all population subgroups with some disparities. SHS was highest among non-Hispanic blacks (46.8%) followed by people living below the poverty level (43.2%), children aged 3–11 years (40.6%), and people that rented their housing (36.8%) in 2011–2012. Of the children children aged 3–11 years, the majority were were non-Hispanic blacks (67.9%), as compared with non-Hispanic whites (37.2%) and Mexican-Americans (29.9%).

Researchers concluded that though a decrease in SHS was seen since 1999–2000, there are still disparities among nonsmokers’ exposure with higher levels seen among non-Hispanic blacks, children, those living below the poverty level, and those who rent their housing. Implementing strategies such as laws prohibiting smoking in workplaces and public places, smoke-free policies in multi-unit housing, and voluntary smoke-free home and vehicle rules were noted as critical to further protect nonsmokers.

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