For this study, we used the dosimeter measures from 6 to 12 months. The nicotine dosimeters were analyzed in Dr Katherine Hammond’s laboratory at University of California at
Berkeley using a standardized protocol (Marbury et al. 1993; Hammond et al. 1995; Glasgow et al. 1998; Eisner et al. 2001). Nicotine was extracted from the filter using an ethanol solution. Sodium hydroxide was added to the Selleckchem PF477736 solution to adjust the pH, and the solution was subsequently analyzed by gas chromatography. Nicotine levels were reported in JNJ-26481585 purchase micrograms/filter. The passive monitors have a limit of detection of 0.01 μg/filter (0.01 μg/m3) (Hammond et al. 1995; Eisner et al. 2001). Race For this study, we assessed race by surveying the primary caregiver. The primary caregiver of each subject was asked to select their child’s race (African American or Black, White, Asian or Asian American, Asian Indian, Native American, Native Hawaiian/Pacific Islander, Middle Eastern) and ethnicity (Hispanic or Non-Hispanic). Because the cohort was primarily African American and White (95%), we excluded other racial and ethnic groups for the purpose of this analysis. Parents were instructed to select as many of the categories as they deemed appropriate. Because there were a few subjects in
other racial and ethnic categories, only those children reported to be African American or White were included in our analysis. Children who were described as African American and White were categorized as mixed-race check details subjects (n = 8). We performed a sensitivity analysis with mixed-race subjects included with African American subjects and then with White subjects to determine whether there were any differences. Since the mixed-race individuals had no impact on the final
results, we included them with African Americans as we have done in our previous studies. Cotinine In addition to air nicotine, we assessed ETS exposure by measuring cotinine levels in children’s serum and hair. We collected serum and hair samples at baseline, 6 and 12 months of the study. Serum cotinine, a short-term measure of tobacco smoke exposure, has a half-life Bcl-w of 15–25 h and reflects tobacco exposure in the prior 3–4 days. Serum samples were analyzed at the CDC’s National Center for Environmental Health using a well-validated protocol (Bernert et al. 1997, 2000; United States Department of Heath and Human Services 1998; Muscat et al. 2002; Ahijevych and Garrett 2004). Briefly, serum samples were analyzed for cotinine using high performance liquid chromatography (HPLC) linked to atmospheric-pressure chemical ionization tandem mass spectrometry. Trichloroacetic acid was added to each specimen followed by potassium hydroxide to neutralize this mixture. Cotinine was extracted using methylene chloride and subsequently injected into the HPLC column. Cotinine was monitored in the eluant by mass spectrometry (limit of detection = 0.05 ng/ml). Hair cotinine levels provided estimates of ETS exposure in the previous 3 months.