Table 5.

Results of conditional logistic regression analysis of serum cotinine level among never smokers

N casesN controlsOR (95% CI)
Overall (ng/mL)
    <1.1 (reference)231161.00
    1.1-2.3331131.57 (0.79-3.13)
    2.4-9.9231211.06 (0.52-2.14)
Men (ng/mL)
    <1.1 (reference)10671.00
    1.1-2.320871.58 (0.61-4.12)
    2.4-9.917891.25 (0.51-3.09)
Women (ng/mL)
    <1.1 (reference)13491.00
    1.1-2.313261.61 (0.59-4.36)
    2.4-9.96320.74 (0.22-2.43)
Age < 55 (ng/mL)
    <1.1 (reference)7371.00
    1.1-2.311272.80 (0.79-9.85)
    2.4-9.98351.64 (0.47-5.72)
Age ≥ 55 (ng/mL)
    <1.1 (reference)16791.00
    1.1-2.322861.20 (0.53-2.74)
    2.4-9.915860.86 (0.37-2.03)
  • NOTE: Self-reported never smokers and long-term quitters with serum cotinine level below 10 ng/mL were included in the analysis (79 cases and 350 controls).