UCSF

Introduction

Differences in the rate of nicotine metabolism between genders and different races have been hypothesized to contribute to disparities in smoking rate, susceptibility to addiction, and ability to quit smoking. The purpose of this study was to determine the effect of race and gender on the rate of nicotine metabolism as indicated by the nicotine metabolite ratio (NMR) in adolescent smokers.

Methods

One hundred and fifty-nine adolescent smokers aged 13-17 were given 2mg of deuterium-labeled cotinine (cotinine-d4). The NMR was calculated as the ratio of concentrations of deuterium-labeled 3'-hydroxycotinine (ng/ml) to cotinine-d4 (ng/ml) in saliva and is a validated biomarker of the rate of nicotine metabolism.

Results

The sample was 67.3% female and racially mixed. On average, Whites had the fastest rates of metabolism compared with both Blacks/African Americans (p < .01) and Asians (p = .01). The NMR was similar between males and females (p = .70). Among the 19 girls who reported using estrogen-containing contraceptives, there was no significant difference in NMR compared with the 83 girls who did not use contraceptives (p = .24) or the 10 who used progestin-only contraceptives (p = .45).

Conclusions

Among adolescent smokers, racial variations in rates of nicotine metabolism were similar to those that have been reported in adult smokers. In contrast to findings in adult smokers, the NMR did not vary significantly by gender or self-reported hormone use.