Table 1.

Characteristics of the study groups (n = 601)

StudyActive smokers (n = 373)Passive smokers (n = 228)
ABCDEF
Demographic data
    Sample size130187597210881
    Subjects with detectable cotinine levels (%)129 (99%)187 (100%)58 (98%)54 (75%)108 (100%)80 (99%)
    Subjects with detectable NNAL levels (%)128 (98%)187 (100%)59 (100%)48 (67%)106 (98%)77 (95%)
    Valid subjects128187584510677
    Sex (male)74 (58%)83 (44%)26 (45%)19 (42%)50 (47%)27 (35%)
    Race-ethnicity (white, non-Hispanic)67 (52%)187 (100%)33 (57%)42 (93%)106 (100%)N.A.
    Age (mean ± SD)38.2 ± 10.936.3 ± 13.8N.A.64.6 ± 5.834.6 ± 16.625.7 ± 7.4
    NationalityUnited StatesPolandUnited StatesUnited StatesPolandMexico
    Cigarettes per day (mean ± SD)18.4 ± 8.215.0 ± 8.46.9 ± 7.1
Analytical data (geometric mean, IQR)
    Cotinine (ng/mL)1,993 (1,180-3,604)928 (646-1,942)389 (127-1,606)0.57 (0.15-2.07)0.93 (0.39-1.74)12.6 (5.60-18.8)
    Cotinine (ng/mg creatinine)2,471 (1,662-4,393)882 (542-1,914)514 (135-1,510)0.85 (0.18-4.15)0.71 (0.32-1.47)10.5 (4.81-16.7)
    NNAL (pg/mL)174 (76.7-367)192 (119-411)91.1 (36.5-231)3.13 (0.92-8.59)4.00 (1.73-7.61)13.9 (8.09-24.5)
    NNAL (pg/mg creatinine)223 (134-386)182 (102-418)120 (51.5-366)4.69 (1.15-10.3)3.04 (1.51-4.76)11.5 (6.83-17.5)
    NNAL/cotinine ratio (×103)0.09 (0.06-0.13)0.21 (0.13-0.31)0.23 (0.12-0.52)5.50 (2.65-11.7)4.31 (2.44-7.36)1.10 (0.60-2.14)

Abbreviations: IQR, interquartile range; N.A., data not available.