Nicotine levels in silicone wristband samplers worn by children exposed to secondhand smoke and electronic cigarette vapor are highly correlated with child’s urinary cotinine.

Introduction:
This text is a manuscript submitted for peer review in the Journal of Exposure analysis and Environmental Epidemiology. It reports a study on the potential of silicone wristbands to measure exposure to tobacco smoke pollutants, specifically nicotine, in children. The study investigates whether nicotine measured in a silicone wristband worn by a child on the wrist for a period of 7 days and 2 days (worn in addition to the first wristband from day 5 to day 7) would correlate with cotinine levels (ng/mL) in the child’s urine obtained at the end of the wearing period. The study also examines the relationship between tobacco smoke pollution, environmental factors, and children's intake.

Key Points:

* The study recruited children who lived with at least one adult who smoked a minimum of 7 cigarettes/week inside the home, children who lived with at least one adult who used electronic cigarettes (EC) at least 4 days/week inside the home and used e-liquids with nicotine, and children not exposed to nicotine products, who lived with adult nonsmokers and nonusers of EC who had a complete ban on smoking and EC use inside their home.
* The study collected urine samples from child participants using procedures from previous studies for analysis of cotinine concentration. Silicone wristbands were transported back to the lab in individual borosilicate amber glass vials, with Thermoset lids lined with F217/PTFE, and stored at -20oC until analysis for nicotine concentration.
* The study found that nicotine was present in 4 of the 31 field blank samples at concentrations of 7.8, 8.0, 9.4 and 9.5 ng/wristband or 0.5% to 1.8% of the levels in the respective exposure samples. all of the field blanks with detectable nicotine levels were from homes with active conventional cigarette smokers.
* The study found a strong correlation between exposure to nicotine as assessed by levels of urine cotinine and exposure to nicotine as assessed by nicotine detected in the wristband. The correlation between urinary cotinine and nicotine in the 2-day wristband was r2 = 0.741, and the correlation between urine cotinine and nicotine in the 7-day wristband was r2 = 0.804.
* The study also found a high correlation between levels of nicotine in the wristband worn for 2 days and the wristband worn for 7 days (r2 = 0.852).
* The study controlled for various factors that may affect concentrations of tobacco smoke pollution near children, such as the amount of tobacco products consumed, proximity to caregivers and visitors using the products, and factors that are more common in low-income children such as a decreased home volume.
* The study also considered factors that affect a child’s intake, such as size, age, and activity level.

Main Message:
The study suggests that silicone wristbands may be a useful tool for epidemiological and intervention studies of tobacco product exposure in children. The wristbands were able to detect nicotine in the presence of cotinine in the child's urine, indicating that they may be effective in measuring exposure to tobacco smoke pollutants. The study also highlights the importance of considering environmental and physiological factors when assessing exposure to tobacco smoke pollutants in children.

quintana PJE, hoh E, Dodder NG, et al. Nicotine levels in silicone wristband samplers worn by children exposed to secondhand smoke and electronic cigarette vapor are highly correlated with child’s urinary cotinine. Journal of exposure science & environmental epidemiology. 2019;29(6):733-741. doi:10.1038/s41370-019-0116-7