Screening for Children’s Exposure to Environmental Tobacco Smoke in a Pediatric Primary Care Setting

Abstract

Purpose of the Study. To develop a brief screening tool to accurately predict environmental tobacco smoke (ETS) exposure. Study Population. A total of 291 healthy children aged 2 weeks to 3 years. These children were recruited from a primary care center that provides care to a low-income population. Exclusion criteria included history of birth at <36 weeks’ gestation, asthma, other chronic pulmonary disease, or cardiac disease. Methods. The primary caregivers of the children in the study filled out a questionnaire that included items on demographics, smoking status of individuals living in the children’s homes, number of cigarettes smoked per day, and the locations in which individuals smoked. Primary caregivers also gave samples of their own and their children’s hair for measurement of levels of cotinine. Results. A total of 7 subjects (2%) had hair cotinine levels of <0.01 ng/mg, 99 subjects (34%) had levels of <0.3 mg/ng, 68 (23%) had midrange levels of 0.3–0.7 ng/mg, and 124 (43%) had levels of >0.7 mg/ng. Factors associated with higher cotinine levels included maternal smoking, the presence of other smokers in the home, and where persons other than the mothers smoke (ie, in the home or outside the home). Interestingly, the reported location of mothers’ smoking (indoors versus outdoors) was not associated with cotinine levels in the hair. The investigators used this information to create a model questionnaire to predict ETS exposure. Three questions were selected: does the mother smoke, do others in the home smoke, do others who smoke remain inside the home or go outside. Using this model, children of mothers who smoke and are also exposed to others who smoke inside the home have an 81% chance of having high exposure to ETS. In contrast, children of mothers who do not smoke and are not exposed to others who smoke have a 64% chance of low exposure to ETS. Conclusions. It was possible to derive a simple and valid screening tool to identify children at risk for ETS exposure, but this tool still needs to be tested prospectively. Reviewer Comments. We all struggle with our patients’ exposure to ETS in the home. Part of the struggle has to do with obtaining accurate information about exposures. The screening tool described in this study needs to be tested prospectively, but it may prove to be highly useful. Of interest is the finding that it did not matter, in terms of levels of cotinine in children’s hair, whether their mothers smoked indoors or reported that they limited themselves to outdoor smoking. We may speculate that this finding has to do with inaccurate reporting (shame about smoking indoors) or to the large amount of particulate residue that remains on smokers after they smoke.