Abstract
Intraindividual variability of measurements of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), nicotine, cotinine, and r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT) over time is uncertain. From 70 habitual smokers’ plasma and urine sampled bimonthly for a year we analysed plasma for NNAL, cotinine and PheT, and urine for NNAL, cotinine and nicotine. We estimated the intraclass correlation coefficients (ρI) for each measurement. Plasma and creatinine-corrected urinary NNAL were stable (ρI ≥70%); plasma PheT and plasma and urinary total cotinine were fairly stable (ρI ≥50%), but urinary nicotine ρI ≈ 40% was not. Except for nicotine, single measurements from plasma or urine adequately represent individual mean exposure over time.
Acknowledgements
This research was partially funded by National Institutes of Health grant DA-13333 to the University of Minnesota.
Declaration of interest
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.