Table 2

Percentage (%) differences (Cot. − SR) and ratios (Cot./SR) of self-reported (SR) and cotinine-verified (Cot.) smokers relative to study variables in men and women aged ≥20 years in the 2008 Korea National Health and Nutrition Examination Survey

Study variablesMenWomen
Number of subjectsSR (%)Cot. (%)Cot. − SR (95% CI)Cot./SR (95% CI)Number of subjectsSR (%)Cot. (%)Cot. − SR (95% CI)Cot./SR (95% CI)
Total238744.750.05.3 (4.3–6.5)1.12 (1.10–1.15)30685.913.98.0 (6.9–8.8)2.36 (2.08–2.61)
Age groups (years)
 20–2928353.060.17.1 (4.2–10.2)1.13 (1.07–1.21)36311.623.411.8 (8.4–15.4)2.02 (1.65–2.58)
 30–3952355.860.85.0 (3.1–7.1)1.09 (1.05–1.13)6085.616.811.2 (8.9–13.7)3.00 (2.35–4.12)
 40–4950549.755.35.6 (3.2–7.9)1.11 (1.06–1.17)5655.814.78.9 (6.5–11.5)2.53 (1.96–3.36)
 50–5941739.845.15.3 (2.6–7.7)1.13 (1.07–1.20)5443.710.16.4 (4.4–8.5)2.73 (1.97–4.15)
 60 or over65931.736.34.6 (2.9–6.4)1.15 (1.09–1.21)9885.310.24.9 (3.5–6.5)1.92 (1.62–2.42)
Education
 Elementary or less47739.644.44.8 (2.7–7.1)1.12 (1.07–1.19)11766.011.25.2 (3.9–6.7)1.87 (1.61–2.28)
 Middle32142.746.74.0 (1.9–6.5)1.09 (1.04–1.16)3054.69.85.2 (3.0–8.0)2.13 (1.55–3.59)
 High85848.053.75.7 (4.2–7.3)1.12 (1.09–1.16)9637.619.211.6 (9.5–13.6)2.53 (2.11–3.11)
 College or higher73145.150.85.7 (3.7–7.7)1.13 (1.08–1.18)6243.912.78.8 (6.6–11.2)3.26 (2.45–4.97)
Occupation
 Non-manual57645.852.36.5 (4.3–8.7)1.14 (1.09–1.20)3756.916.89.9 (6.7–12.8)2.43 (1.84–3.44)
 Manual127647.452.24.8 (3.4–6.2)1.10 (1.07–1.13)10716.315.08.7 (7.0–10.6)2.38 (1.99–2.92)
 Others53537.242.45.2 (3.4–7.3)1.14 (1.09–1.20)16225.412.57.1 (5.7–8.4)2.31 (1.97–2.76)
Current marital status
 Married with cohabiting187742.547.75.2 (4.0–6.3)1.12 (1.09–1.15)20744.212.58.3 (7.1–9.5)2.98 (2.55–3.64)
 Married without cohabiting3452.955.93.0 (0.0–11.8)1.06 (1.00–1.24)496.18.22.1 (0.0–6.1)1.34 (1.00–3.00)
 Never-married37153.959.85.9 (3.5–8.6)1.11 (1.06–1.16)30013.022.79.7 (6.0–13.7)1.75 (1.43–2.22)
 Divorced or widowed10549.554.34.8 (1.0–9.5)1.10 (1.02–1.21)6458.214.76.5 (4.6–8.5)1.79 (1.52–2.22)
Cohabiting with parents
 Yes53249.355.36.0 (3.9–8.1)1.12 (1.08–1.17)5094.715.510.8 (8.1–13.6)3.30 (2.43–5.15)
 No185543.548.55.0 (3.9–6.2)1.11 (1.09–1.15)25596.113.67.5 (6.4–8.5)2.23 (1.98–2.52)
Residential area
 Seoul39443.948.24.3 (1.5–7.1)1.10 (1.03–1.17)5157.813.45.6 (3.7–8.0)1.72 (1.44–2.20)
 Other cities137546.151.65.5 (4.2–6.8)1.12 (1.09–1.15)17346.315.59.2 (7.8–10.7)2.46 (2.14–2.86)
 Rural area61842.247.65.4 (3.6–7.3)1.13 (1.08–1.18)8193.810.76.9 (5.1–8.7)2.82 (2.14–3.93)
Secondhand smoking exposure
 None11643842.54.5 (3.3–6.0)1.12 (1.08–1.16)19203.38.55.2 (4.2–6.3)2.58 (2.17–3.24)
 <1 h/day77844.649.95.3 (3.7–6.9)1.12 (1.08–1.16)6058.418.810.4 (8.1–13.1)2.24 (1.85–2.82)
 ≥1 h/day39363.470.77.3 (4.6–10.2)1.12 (1.07–1.17)46012.829.416.6 (12.7–2.02)2.30 (1.88–2.85)
 Unknown5257.763.55.8 (0.0–11.5)1.10 (1.00–1.25)839.615.76.1 (1.2–12.0)1.64 (1.13–3.00)
  • CI, confidence interval.