Table 2. Odds ratios (95% confidence intervals) comparing those who initiate smoking with never smokers: non-smokers vs. ever smokers.
| Non-smokers (N = 8,417) | Ever smokers (N = 16,073) | OR (95% CI) a | OR (95% CI) b | ||
|---|---|---|---|---|---|
| Demographic characteristics | |||||
| Birth cohort | 1935–1939 | 570 (6.8) | 753 (4.7) | 1 (reference) | 1 (reference) |
| 1940–1949 | 3,055 (36.3) | 4,963 (30.9) | 1.23 (1.09–1.38) | 1.17 (1.03–1.32) | |
| 1950–1959 | 2,904 (34.5) | 6,326 (39.4) | 1.65 (1.47–1.85) | 1.51 (1.33–1.72) | |
| 1960- | 1,888 (22.4) | 4,031 (25.1) | 1.62 (1.43–1.83) | 1.46 (1.27–1.67) | |
| Obesity c | Normal | 5,061 (60.1) | 9,447 (58.8) | 1 (reference) | 1 (reference) |
| Obese | 3,345 (39.8) | 6,616 (41.2) | 1.06 (1.00–1.12) | 1.04 (0.99–1.10) | |
| Marital status | Single | 358 (4.3) | 906 (5.6) | 1 (reference) | 1 (reference) |
| Married d | 7,967 (94.6) | 15,044 (93.6) | 0.75 (0.66–0.85) | 0.83 (0.73–0.94) | |
| Education | ≤ Middle school | 2,179 (25.9) | 4,248 (26.4) | 1 (reference) | 1 (reference) |
| High school graduate | 3,005 (35.7) | 6,807 (42.4) | 1.16 (1.09–1.24) | 1.10 (1.02–1.18) | |
| ≥ University degree | 3,029 (36.0) | 4,763 (29.6) | 0.81 (0.75–0.86) | 0.84 (0.77–0.91) | |
| Occupation | Manual | 3,656 (43.4) | 7,914 (49.2) | 1 (reference) | 1 (reference) |
| Non-manual | 2,736 (32.5) | 4,668 (29.0) | 0.79 (0.74–0.84) | 0.86 (0.80–0.93) | |
| Unemployed | 1,619 (19.2) | 2,860 (17.8) | 0.82 (0.76–0.88) | 1.10 (1.01–1.19) | |
| Alcohol drinking | Current drinkers | 2,902 (34.5) | 2,404 (15.0) | 1 (reference) | 1 (reference) |
| Ex-drinkers | 475 (5.6) | 1,345 (8.4) | 1.16 (1.04–1.29) | 1.17 (1.05–1.31) | |
| Never drinkers | 5,025 (59.7) | 12,309 (76.6) | 0.34 (0.32–0.36) | 0.36 (0.34–0.38) | |
| Disease history | |||||
| Stroke | 155 (1.8) | 297 (1.9) | 1.00 (0.83–1.22) | 1.10 (0.89–1.35) | |
| Myocardial infarction | 274 (3.3) | 574 (3.6) | 1.10 (0.95–1.27) | 1.26 (1.08–1.47) | |
| Hypertension | 1,920 (22.8) | 3,332 (20.7) | 0.88 (0.83–0.94) | 0.86 (0.80–0.92) | |
| Diabetes mellitus | 721 (8.6) | 1,470 (9.2) | 1.07 (0.98–1.18) | 1.16 (1.05–1.28) | |
| Respiratory disease e | 213 (2.5) | 435 (2.7) | 1.07 (0.91–1.27) | 1.14 (0.96–1.35) | |
| Cancer | 129 (1.5) | 295 (1.8) | 1.20 (0.98–1.48) | 1.42 (1.14–1.78) | |
| Smoking-related history | |||||
| Secondhand smoke | Unexposed | 6,285 (74.7) | 9,468 (58.9) | 1 (reference) | 1 (reference) |
| Exposed at home/work | 2,048 (24.3) | 6,504 (40.5) | 2.11 (1.99–2.24) | 1.91 (1.79–2.03) | |
Unknown values were wholly included in the statistical models but were not presented in the table.
a. Adjusted for birth cohort, obese status, marital status, smoking status, education, occupational classification, alcohol drinking, and history of diseases
b. Adjusted for birth cohort, obese status, marital status, smoking status, education, occupational classification, alcohol drinking, history of diseases, and secondhand smoke exposure
c. Body mass index < 25 kg/m2 (normal) vs. body mass index ≥ 25 kg/m2 (obese)
d. Married peoples including cohabitants
e. Ever diagnosed with chronic bronchitis and/or asthma