Skip to main content
. Author manuscript; available in PMC: 2017 Sep 21.
Published in final edited form as: Ann Intern Med. 2017 Feb 7;166(6):390–400. doi: 10.7326/M16-1107

Figure 1. Urinary and salivary nicotine metabolite levels by group^.

Figure 1

^Boxplots show median with interquartile range, IQR (25%-75%); error bars show Tukey’s whiskers and cross indicates arithmetic mean (geometric means are provided in Table S1); Solid grey circles show outliers; *Measured in urine: data are raw values divided by ratio of observed to covariate-adjusted creatinine levels; values below the limit of detection (LOD) were imputed by LOD divided by square root of 2; †Measured in saliva; There were no significant differences between groups; NRT – Nicotine replacement therapy; EC – Electronic cigarette; Cig-Cigarette