Nicotine dependence and biochemical exposure measures in the second trimester of pregnancy

Kwok, T'ng Chang and Taggar, Jaspal and Cooper, Sue and Lewis, Sarah and Coleman, Tim (2014) Nicotine dependence and biochemical exposure measures in the second trimester of pregnancy. Nicotine & Tobacco Research, 16 (2). pp. 145-154. ISSN 1462-2203

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Abstract

Introduction: The Heaviness of Smoking Index (HSI) is validated to measure nicotine dependence in nonpregnant smokers,

and in these smokers, mean salivary and serum cotinine levels are related by a ratio of 1.25. However, as nicotine metabolism

increases during gestation, these findings may differ in pregnancy. We investigated the validity of HSI in pregnancy by comparing

this with 3 biochemical measures; and in a search for a less-invasive cotinine measure in pregnancy, we also explored the

relationship between mean blood and salivary cotinine levels.

Methods: Cross-sectional analyses using baseline data from the Smoking, Nicotine, and Pregnancy Trial. Participants were

16–46 years old, 12–24 weeks gestation, smoked more than 5 cigarettes per day and had exhaled carbon monoxide (CO) readings

of at least 8 ppm. Linear regression was used to examine correlations between HSI and blood cotinine, and salivary cotinine

and exhaled CO. Correlation between blood and salivary cotinine was investigated using linear regression through the origin.

Results: HSI scores were associated with blood cotinine (R2 = 0.20, n = 662, p < .001), salivary cotinine (R2 = 0.11, n = 967,

p < .001), and exhaled CO (R2 = 0.13, n = 1,050, p < .001). Salivary and blood cotinine levels, taken simultaneously, were highly

correlated (R2 = 0.91, n = 628, p < .001) and the saliva:blood level ratio was 1.01 (95% CI 0.99–1.04).

Conclusions: Correlations between HSI and biochemical measures in pregnancy were comparable with those obtained outside

pregnancy, suggesting that HSI has similar validity in pregnant smokers. Salivary and blood cotinine levels are roughly equivalent

in pregnant smokers.

Item Type: Article
Schools/Departments: University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Medicine > Division of Primary Care
University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Medicine > Division of Epidemiology and Public Health
Identification Number: https://doi.org/10.1093/ntr/ntt127
Depositing User: de Sousa, Mrs Shona
Date Deposited: 03 Apr 2014 09:42
Last Modified: 17 Sep 2016 07:16
URI: http://eprints.nottingham.ac.uk/id/eprint/2854

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