Sources of Tobacco Smoke Exposure and Their Associations with Serum Cotinine Levels among U.S. Children and Adolescents


 
 
 We assessed tobacco smoke exposure (TSE) levels based on private and public locations of TSE according to race/ethnicity among U.S. school-aged children ages 6-11 years and adolescents ages 12-17 years.
 
 
 
 Data were from 5,296 children and adolescents who participated in the National Health and Nutrition Examination Survey (NHANES) 2013-2018. Racial/ethnic groups were non-Hispanic White, Black, Other/Multiracial, and Hispanic. NHANES assessed serum cotinine and the following TSE locations: homes and whether smokers did not smoke indoors (home thirdhand smoke (THS) exposure proxy) or smoked indoors (secondhand (SHS) and THS exposure proxy), cars, in other homes, restaurants, or any other indoor area. We used stratified weighted linear regression models by racial/ethnic groups and assessed the variance in cotinine levels explained by each location within each age group.
 
 
 
 Among 6-11-year-olds, exposure to home THS only and home SHS+THS predicted higher log-cotinine among all racial/ethnic groups. Non-Hispanic White children exposed to car TSE had higher log-cotinine (β=1.64, 95%CI=0.91,2.37) compared to those unexposed. Non-Hispanic Other/Multiracial children exposed to restaurant TSE had higher log-cotinine (β=1.13, 95%CI=0.23,2.03) compared to those unexposed. Among 12-17-year-olds, home SHS+THS exposure predicted higher log-cotinine among all racial/ethnic groups, except for non-Hispanic Black adolescents. Car TSE predicted higher log-cotinine among all racial/ethnic groups. Non-Hispanic Black adolescents with TSE in another indoor area had higher log-cotinine (β=2.84, 95%CI=0.85,4.83) compared to those unexposed.
 
 
 
 TSE location was uniquely associated with cotinine levels by race/ethnicity. Smoke-free home and car legislation are needed to reduce TSE among children and adolescents of all racial/ethnic backgrounds.
 
 
 
 Racial/ethnic disparities in tobacco smoke exposure (TSE) trends have remained stable among U.S. children and adolescents over time. This study’s results indicate that TSE locations differentially contribute to biochemically-measured TSE within racial/ethnic groups. Home TSE significantly contributed to cotinine levels among school-aged children 6-11 years old, and car TSE significantly contributed to cotinine levels among adolescents 12-17 years old. Racial/ethnic differences in locations of TSE were observed among each age group. Study findings provide unique insight into TSE sources, and indicate that home and car smoke-free legislation have great potential to reduce TSE among youth of all racial/ethnic backgrounds.
