Urinary Nicotine and Cotinine as a Method for Assessing the Effectiveness of an Intervention to Aid Smoking Cessation During Pregnancy

Abstract

PURPOSE: Smoking cessation during pregnancy has been shown to be beneficial to both the child and mother. Within the context of randomized controlled trials, using a biomarker to assess success or failure may help avoid misclassification do to misreporting by the participant. The aim of this study was to assess the feasibility of using urinary nicotine and cotinine as an indicator of smoking cessation during pregnancy within the context of a randomized controlled trial. METHODS: The M-SCOPE study is a 2 group parallel randomized control trial (RCT) among pregnant smokers in Greece (n=84) that were randomly assigned to an intervention for smoking cessation or a control group. The control group/low intensity intervention included: brief advice for 5 minutes and a short leaflet, while the experimental group/intensive intervention included: 30 minutes of individualized cognitive-behavioral intervention and a self-help manual for smoking cessation during pregnancy. Urine samples for biomarker analysis of cotinine and nicotine were collected at two time points: at baseline and around the 32nd week of gestation and analyzed for their nicotine/cotinine content using LC/MS. RESULTS: Within the context of our study, urinary nicotine was found to decrease by 190 ng/ml in the intervention group (from 443 to 253 ng/ml, p=0.05), while urinary cotinine by 140 ng/ml (from 452 to 312 ng/ml, p=0.016) among intervention group participants. On the contrary, among control group participants urinary nicotine and cotinine concentrations were not found to decrease (cotinine: from 561 to 737 ng/ml, p=0.551 and nicotine: 891 to 1040 ng/ml, p=0.423). Comparing the two metabolites (nicotine vs. cotinine), the latter was found to be associated statistically stronger with smoking cessation. CONCLUSIONS: Urinary nicotine and cotinine were successful indicators of smoking cessation during pregnancy, and were found to decrease among participants after smoking cessation, with the latter found to be a statistically stronger marker.