Figure 3.

Nicotine metabolites and recent smoking. A: sputum nicotine was increased in active smokers who reported smoking >10 cigarettes within 24 h before the study visit (AS >10, n = 227) vs. active smokers who reported no smoking within 24 h before the study visit (AS 0, n = 20). Sputum nicotine was increased in both groups relative to never smokers (NSs). B: similar pattern for sputum cotinine, with increases in both the AS 0 and AS >10 groups relative to NS, with the AS >10 group higher than the AS 0. C: the pattern for urine cotinine was similar to that for sputum cotinine. D: subjects in the AS 0 group reported fewer average cigarettes smoked per day than those in the AS >10 group. ***P < 0.001 by ANOVA with Tukey’s posttest (A–C) or Student’s t test (D). Cig, cigarettes.