Environmental tobacco smoke and childhood asthma - Tips from Other Journals

Date: Oct, 1993

An estimated 2 to 5 million children in the United States have asthma. Numerous studies have suggested that asthma is adversely affected by environmental exposure to tobacco smoke. To date, these studies have relied on parental reports of tobacco use. Chilmonczyk and colleagues assessed the impact of environmental tobacco smoke on childhood asthma by measuring urine cotinine, a metabolic derivative of nicotine.

Urine cotinine levels were determined in 199 children with asthma. In 145 of these children, the investigators measured pulmonary function and documented exacerbations of asthma through blinded reviews of the medical records. Parental reports indicated that 83 (42 percent) of the 199 children had been exposed to environmental tobacco smoke.

Median urine cotinine levels were 6 ng per mL in the 116 children without reported exposure to environmental tobacco smoke, compared with 13 ng per mL in the 53 children exposed to smoke by their mother or other people and 56 ng per mL in the 30 children exposed to smoke by both their mother and other people.

The relative risk of asthma exacerbation was 1.8 (based on parental reports) and 1.7 (based on urine cotinine levels) for children in the highest exposure category, compared with children in the lowest exposure category. In addition, a variety of pulmonary function measures, such as the forced expiratory flow volume, were significantly decreased with both reported and measured environmental tobacco smoke exposure.

The authors conclude that exposure to environmental tobacco smoke, as measured by urine cotinine levels and parental reports, is associated with exacerbations of childhood asthma.

In a related editorial, Boyle notes that the Environmental Protection Agency recently concluded on the basis of 30 epidemiologic studies that environmental tobacco smoke is a human lung carcinogen. The study by Chilmonczyk and colleagues, which used urine cotinine levels as a biologic marker of exposure to environmental tobacco smoke, strengthens the case for causality.

COPYRIGHT 1993 American Academy of Family PhysiciansCOPYRIGHT 2004 Gale Group

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