Table 3

Gender differences and ratios in percentages (%) of self-reported non-smokers among cotinine-verified smokers relative to demographic variables in men and women aged ≥20 years in the 2008 Korea National Health and Nutrition Examination Survey

Study variablesMenWomenGender differences and ratios
Total number of subjects (%)Self-reported non-smokers (%, 95% CI) ATotal number of subjects (%)Self-reported non-smokers (% 95% CI) BB − A (95% CI)B/A (95% CI)
Total1194 (100.0)12.1 (10.2–13.9)426 (100.0)58.9 (54.3–63.6)45.4 (40.3–50.5)4.85 (4.13–5.70)
Age groups (years)
 20–29170 (14.2)12.4 (7.4–17.3)85 (20.0)52.9 (42.3–63.6)39.5 (29.9–49.0)4.51 (3.18–6.38)
 30–39318 (26.6)8.8 (5.7–11.9)102 (23.9)66.7 (57.5–75.8)51.8 (41.5–62.1)6.90 (4.84–9.84)
 40–49279 (23.4)12.5 (8.7–16.4)83 (19.5)61.5 (51.0–71.9)50.7 (40.0–61.5)4.90 (3.59–6.67)
 50–59188 (15.8)13.8 (8.9–18.8)55 (12.9)65.5 (52.9–78.0)54.8 (40.6–68.9)5.00 (3.41–7.34)
 60 or over239 (20.0)14.2 (9.8–18.7)101 (23.7)50.5 (40.7–60.3)31.7 (17.9–45.5)3.14 (2.00–4.93)
Education
 Elementary or less212 (17.8)11.8 (7.5–16.1)132 (31.0)49.2 (40.7–57.8)32.2 (20.8–43.5)4.05 (2.48–6.64)
 Middle150 (12.6)10.0 (5.2–14.8)30 (7.0)53.3 (35.5–71.2)37.8 (18.1–57.5)4.83 (2.64–8.85)
 High461 (38.6)12.2 (9.2–15.1)185 (43.4)62.2 (55.2–69.2)48.2 (41.0–55.4)5.22 (4.10–6.66)
 College or higher371 (31.1)12.9 (9.5–16.4)79 (18.5)69.6 (59.5–79.8)55.2 (45.1–65.2)5.12 (3.93–6.66)
Occupation
 Non-manual301 (25.2)13.3 (9.5–17.1)63 (14.8)60.3 (48.2–72.4)43.0 (31.3–54.8)4.19 (3.05–5.76)
 Manual666 (55.8)11.3 (8.9–13.7)161 (37.8)60.3 (52.7–67.8)46.9 (38.3–55.5)5.39 (4.22–6.90)
 Others227 (19.0)12.8 (8.4–17.1)202 (47.4)57.4 (50.6–64.2)44.6 (36.7–52.5)4.55 (3.27–6.33)
Current marital status
 Married with cohabiting896 (75.0)12.8 (10.6–15.0)259 (60.8)68.0 (62.3–73.6)54.2 (47.8–60.6)5.38 (4.46–6.48)
 Married without cohabiting19 (1.6)5.3 (0.0–15.3)4 (0.9)25.0 (0.0–67.4)15.3 (−23.5 to 54.2)3.22 (0.33–31.85)
 Never-married222 (18.6)10.4 (6.4–14.4)68 (16.0)45.6 (33.8–57.4)36.8 (26.4–47.1)4.70 (3.25–6.78)
 Divorced or widowed57 (4.8)8.8 (1.4–16.1)95 (22.3)45.3 (35.3–55.3)27.8 (13.0–42.7)2.82 (1.45–5.49)
Cohabiting with parents
 Yes294 (24.6)11.6 (7.9–15.2)79 (18.5)70.9 (60.9–80.9)59.7 (50.2–69.1)6.40 (4.78–8.58)
 No900 (75.4)12.2 (10.1–14.4)347 (81.5)56.2 (51.0–61.4)40.7 (34.8–46.6)4.37 (3.60–5.30)
Residential area
 Seoul190 (15.9)12.1 (7.5–16.7)69 (16.2)42.0 (30.4–53.7)29.5 (17.8–41.2)3.48 (2.31–5.22)
 Other cities710 (59.5)12.0 (9.6–14.4)269 (63.2)60.6 (54.8–66.4)48.1 (41.9–54.3)5.10 (4.17–6.23)
 Rural area2947 (24.6)12.2 (8.5–16.0)88 (20.7)67.1 (57.2–76.9)53.5 (40.4–66.6)5.54 (3.76–8.16)
Urine cotinine (ng/ml)
 50–499321 (26.9)33.6 (28.5–38.8)247 (58.0)79.0 (73.9–84.0)41.3 (34.0–48.6)2.19 (1.87–2.56)
 500–999268 (22.5)7.5 (4.3–10.6)97 (22.8)32.0 (22.7–41.2)28.4 (18.5–38.3)4.60 (2.93–7.23)
 1000–1499239 (20.0)3.8 (1.4–6.2)41 (9.6)41.5 (26.4–56.5)36.2 (20.4–52.0)10.45 (5.27–20.72)
 ≥1500366 (30.7)1.9 (0.5–3.3)41 (9.6)19.5 (7.4–31.6)14.4 (2.7–26.2)9.06 (3.42–24.02)
Secondhand smoking exposure
 None495 (41.5)12.7 (9.8–15.7)164 (38.5)63.4 (56.0–70.8)50.1 (41.6–58.6)4.90 (3.82–6.28)
 <1 h/day388 (32.5)11.3 (8.2–14.5)114 (26.8)55.3 (46.1–64.4)41.7 (32.3–51.1)4.99 (3.66–6.80)
 ≥1 h/day278 (23.3)12.2 (8.4–16.1)135 (31.7)58.5 (50.2–66.8)45.6 (36.7–54.5)4.86 (3.57–6.62)
 Unknown33 (2.8)9.1 (0.0–18.9)13 (3.1)38.5 (12.0–64.9)23.7 (−5.2–52.5)2.84 (0.98–8.20)
  • CI, confidence interval.