Environmental tobacco smoke and serum vitamin C levels in children.

BACKGROUND

High levels of free radicals in tobacco smoke are thought to be responsible for decreased levels of serum ascorbic acid in smokers and adults exposed to environmental tobacco smoke (ETS). The association of ETS to serum ascorbic acid in children is unknown.

METHODS

Data were analyzed from the Third National Health and Nutrition Examination Survey, a nationally representative sample of children and adolescents (n = 2968). Comprehensive data including serum cotinine levels and family smoking patterns allowed for analysis of relationship of ETS to serum ascorbic acid levels. Data from 24-hour dietary recall also allowed for the control of vitamin C intake. Children were divided into categories of low and high ETS exposure based on levels of serum cotinine above or below 2 ng/mL. Smokers were defined by either self-report or serum cotinine >15 ng/mL.

RESULTS

Although there was a trend for lower levels of vitamin C intake in children with higher levels of ETS exposure, this trend did not reach statistical significance. Among all children, serum ascorbic acid levels were linearly related to serum cotinine levels (r = 0.19). In addition, a dose-response relationship was observed between levels of tobacco exposure and serum ascorbic acid levels. After adjusting for age, gender, vitamin C intake, and multivitamin use, environmental tobacco exposure remained significantly associated with lower levels of serum ascorbic acid in children who were exposed to both high and low levels of ETS.

CONCLUSION

Exposure of children to ETS leads to significant alterations in serum ascorbic acid levels. Therefore, this study further highlights the potential dangers of ETS to children.