Measuring nicotine intake among highly-dependent adolescent smokers: Comparability of saliva and plasma cotinine concentrations

Abstract

Cotinine is the most common biomarker used to assess nicotine exposure and abstinence. It can be measured in various matrices including saliva, plasma, and urine. Previous research with adults has shown high correlations between saliva and plasma cotinine concentrations. However, research has not examined this relationship in adolescents. Additionally, variability in saliva flow and metabolism across gender, ethnicity, and age may impact the relationship between saliva and plasma cotinine concentration. Our aim was to examine the relationship between saliva and plasma cotinine concentration in a group of nicotine-dependent adolescent smokers. Additionally, we examined these correlations across gender, ethnicity and age. The sample consisted of 66 adolescent smokers (age 15.1 ± 1.3, 63.6% girls, 66.7% European American, CPD 18.3 ± 8.5, FTND 7.1 ± 1.3). Saliva and plasma specimens were collected before the treatment phase of a nicotine replacement therapy trial and analyzed. The relationship between saliva and plasma cotinine concentration was analyzed using Pearson's correlation coefficients. We performed a secondary analysis using multiple regression to compare correlations across race, gender and age. Results indicated a positive correlation between saliva cotinine and plasma cotinine concentration (r = .84, p < .001). Differences in correlations across age were significant (t = 3.03, p < .01). Differences across ethnicity approached significance (t = −1.93, p = .058). Future research should seek to further validate saliva-to-plasma cotinine concentration ratios in adolescents as well as characterize saliva-to-plasma concentration differences and their underlying mechanisms.

Comparison of Liquid Chromatography Mass Spectrometry and Enzyme-Linked Immunosorbent Assay Methods to Measure Salivary Cotinine Levels in Ill Children

“…Nevertheless, other studies have found salivary cotinine levels to be comparable to plasma cotinine levels in adolescent and adult smokers [42,43], although levels are approximately 10% to 40% higher [1,[42][43][44]. Additionally, our saliva collection method (i.e., the use of cotton swabs as recommended by Salimetrics [32]) may have resulted in differential salivary flow rate which also could have affected cotinine levels [42]. Further, the timing of saliva collection may have lowered cotinine levels if saliva was obtained after the child had been in the PED/UC for a while, since cotinine has a mean half-life of 16-18 h [8].…”

“…All of these factors were highly variable in our population of ill children. Nevertheless, other studies have found salivary cotinine levels to be comparable to plasma cotinine levels in adolescent and adult smokers [42,43], although levels are approximately 10% to 40% higher [1,[42][43][44]. Additionally, our saliva collection method (i.e., the use of cotton swabs as recommended by Salimetrics [32]) may have resulted in differential salivary flow rate which also could have affected cotinine levels [42].…”

Nicotine Addiction and Hearing Loss in Young Subjects From Beirut, Lebanon

“…Plasma cotinine concentration is highly correlated with tobacco smoke exposure (12). tical problems in a research setting.…”

Discrepancies in the Validity of Self-Reported Cigarette Smoking in Adults With and Without ADHD

“…Salivary cotinine is minimally invasive in nature and has increased sensitivity (Connor Gorber et al, 2009). Since salivary cotinine is a comparable measure to plasma cotinine (Benowitz et al, 2009;Bernert et al, 2000;Jarvis et al, 2003;Parzynski et al, 2008;SRNT, 2002), the cotinine cutoffs proposed by Benowitz and colleagues (Benowitz et al, 2009) were used for analysis. The salivary sample was collected, stored in a freezer, and analyzed by Salimetrics as cotinine values in ng/mL units.…”