Table 3

 Prevalence of secondhand smoke (SHS) exposure (cotinine levels ⩾0.05 ng/ml) among non-smoking adults by selected characteristics

CharacteristicsnPercentage with measured SHS exposure† (95% CI)
*p<0.05.
†Cotinine levels ⩾LOD (0.05 ng/ml).
‡Self-reported.
§Referent category used to test the null hypothesis of no difference in proportions using the t test.
Total586639.1 (35.2 to 43.1)
Smoke-free law coverage
    No law§402645.9 (42.4 to 49.4)
    Limited50335.1 (24.0 to 48.0)
    Extensive133712.5 (8.5 to 18.0)*
Workplace SHS exposure‡
    Yes43666.5 (58.2 to 73.9)*
    No542836.5 (32.8 to 40.3)
Restaurant meals/week
    0 to 3467036.1 (32.2 to 40.2)*
    4+119447.5 (42.1 to 53.1)
Sex
    Men250345.4 (40.3 to 50.5)*
    Women336334.2 (30.7 to 37.9)
Race/ethnicity
    Non-Hispanic white§294035.4 (30.8 to 40.4)
    Non-Hispanic black90863.8 (58.8 to 68.5) *
    Mexican American153437.5 (32.9 to 42.4)
Age group
    20–39 years194945.6 (40.2 to 51.1)*
    40–59 years162937.6 (33.2 to 42.1)*
    60+ years§228832.6 (28.9 to 36.5)
Education
    ⩽12 years306147.2 (43.6 to 50.8)*
    >12 years279533.6 (29.6 to 37.9)