Acute physiologic effects of secondhand smoke exposure in children

We investigated the hypothesis that exhaled carbon monoxide (eCO), heart rate (HR), and blood pressure (BP) would increase acutely in exposed but not in unexposed children. In a nonrandomized controlled design, parent-child dyads were assigned to groups based on exposure: child subjects, 7-18 years of age, exposed to smoking daily in the home (exposed) or with no household exposure (unexposed control). HR, BP, and eCO were measured before and after exposure to a parent smoking 1 cigarette (exposed) or a time-lapse equivalent (control). The primary analysis compared mean acute changes in physiological measures following intervention or control procedure. Forty-one dyads were enrolled. At baseline, no differences in child gender, race, ethnicity, HR, BP, lipids, or fasting glucose were noted between exposure groups. Following experimental or control procedures, the median change in eCO was similar between groups (-0.1 ppm exposed vs. 0.0 ppm unexposed, p = .27). Acute hemodynamic changes were also similar between exposed and unexposed children, respectively: (HR change 4.2 vs. 2.6 beats per minute, p = .62; systolic blood pressure change 0.08 vs. 0.41 mm Hg, p = .91; diastolic blood pressure 0.08 vs. 2.27 mm Hg, p = .37). This is the first study to report on acute physiologic changes of secondhand smoke exposure in children in a naturalistic setting. A single acute dose of passive smoke exposure in children did not alter the physiologic variables of HR or BP. Further in-home study using continuous monitoring is needed. Demonstration of acute effects may serve as clinical feedback to motivate parents to quit smoking.