Fig. 4From: Simultaneous measurement of urinary total nicotine and cotinine as biomarkers of active and passive smoking among Japanese individualsCorrelations between number of cigarettes smoked per day and nicotine metabolite concentrations in 219 urine samples. Data are shown as total (free + glucuronide) values. Spearman’s rank correlation coefficients (p value) for nicotine and cotinine were 0.84 (<0.0001) and 0.85 (<0.0001), respectivelyBack to article page