The Peer and Family Smoking Index: A Valid Measure of Secondhand Smoke Exposure in Adolescents.

Objective: Nearly half of all adolescents in the United States are exposed to secondhand smoke (SHS) daily, primarily at home, resulting in respiratory infections, asthma exacerbations, and reduced lung function. A concise self-report measure is needed to identity adolescents exposed to SHS. The purpose of this study was to test whether nonsmoking adolescents who reported exposure to peer and/or family smoking on the Peer and Family Smoking Index had higher salivary cotinine levels than those reporting no exposure to either peer or family smoking.

Methods: A convenience sample of 135 English-speaking adolescents ages 15-18 years was recruited from two high schools. Those who reported use of nicotine replacement therapy, cigarette smoking (past 30 days), smokeless tobacco use (past 30 days), or who self-reported pregnancy were excluded. Salivary cotinine and self-report data from the Peer and Family Smoking Index were collected after obtaining parental consent and assent from the adolescent.

Results: Mean salivary cotinine levels differed by exposure group (none, family, peer, or family and peer), F (3, 130) = 5.44, p = .001. The post hoc analysis identified a significantly higher mean cotinine level among those exposed to SHS from both family and peers than among those with no exposure (p = .001).

Conclusions: Known groups validity of the index was supported. Adolescents who reported family smoking or a combination of family and peer smoking had significantly higher salivary cotinine levels than unexposed adolescents. The Peer and Family Smoking Index is a concise and valid self-report measure for SHS exposure in adolescents.