Determination of tobacco smoke exposure by plasma cotinine levels in infants and children attending urban public hospital clinics

摘要

Objective: To determine the prevalence of second-hand smoke (SHS) exposure among infants and young children who received preventive care at pediatric preventative care clinics associated with an urban public hospital. Cotinine, a metabolite of nicotine, has been used to study SHS exposure in population-based studies of children 3 years of age or older. Design: Retrospective study using a convenience sample. Setting: Urban county pediatric primary care clinics in San Francisco, California. Participants: A total of 496 infants and children (mean [SD] age, 2.4 [1.9] years). Interventions: Discarded plasma samples (which were routinely collected for lead screening) were tested, and medical records were reviewed, for SHS exposure. Main Outcome Measure: Secondhand smoke exposure based on cotinine plasma level and history of exposure in the medical record. Results: Thirteen percent of parents reported that their child was exposed to SHS, yet biochemical testing detected cotinine in 55% of samples, at a geometric mean (SD) of 0.23 (3.55) ng/mL. There were no significant sex or age differences. African American children had much higher mean cotinine levels than did Latino children (geometric mean difference, 6.07 ng/mL [95% CI, 4.37 to 8.43 ng/mL]). Conclusion: In a city with a low smoking rate (12%) and public smoking bans, we documented 55% exposure among infants and young children, using a plasma biomarker, compared with 13% exposure reported by parents. Because SHS is associated with significant respiratory diseases and parents underreport exposure, routine biochemical screening should be considered as a tool to identify and reduce SHS exposure.