Comparison between self-report and a dipstick method (NicCheck 1) to assess nicotine intake.

The purpose of this study was to investigate the agreement between self-reported tobacco consumption and NicCheck 1 (Dynagen Inc. Cambridge, Mass., USA) regarding smoking status and nicotine intake in a population of smokers (20.8%) and non-smokers. NicCheck 1 is a dipstick that changes colour in the presence of urinary nicotine metabolites. Smoking was assessed by self-report and NicCheck 1 in 169 males and 191 females (mean age 36.0 SD 0.7). Self-report and NicCheck 1 agreed highly on smoking status, especially in moderate to heavy smokers. With regard to nicotine intake, there was a large overlap in self-reported tobacco consumption between NicCheck 1 levels, despite a relatively high correlation coefficient between self-report and NicCheck 1 in smokers (i.e. 0.74). No effect modification by gender or BMI was found. When both methods were validated against two blood lipid parameters, self-report seemed to do equally well as NicCheck 1 in assessing nicotine intake.