Table 1.
The distributions of specific characteristics by cases and controls status
| Variables | Cases | Controls | |
|---|---|---|---|
| N = 190 (%) | N = 380 (%) | OR (95% CI)a | |
| Gender | |||
| Male | 115 (60.5%) | 230 (60.5%) | 1.00 (0.84–1.20) |
| Female | 75 (39.5%) | 150 (39.5%) | Ref. |
| Age (years; mean ± SD) | 65.5 ± 11.9 | 64.4 ± 11.8 | |
| ≥ 60 | 132 (69.5%) | 252 (66.3%) | 1.02 (1.01–1.04)** |
| 51–59 | 38 (20.0%) | 88 (23.2%) | 0.93 (0.78–1.11) |
| ≤ 50 | 20 (10.5%) | 40 (10.5%) | Ref. |
| Smoking status | |||
| Current or ever smokers | 102 (53.7%) | 118 (31.1%) | 2.20 (1.84–2.63)*** |
| Nonsmokers | 88 (46.3%) | 262 (68.9%) | Ref. |
| Pack-years smoked | |||
| ≥ 40 | 65 (34.2%) | 60 (15.8%) | 2.46 (2.43–2.50)*** |
| 1–39 | 37 (19.5%) | 58 (15.3%) | 1.90 (1.59–2.28)*** |
| 0 | 88 (46.3%) | 262 (68.9%) | Ref. |
| Green tea consumption (cup/day) | |||
| 0 | 146 (76.8%) | 250 (65.8%) | 1.71 (1.68–1.73)*** |
| < 1 | 29 (15.3%) | 54 (14.2%) | 1.65 (1.38–1.98)** |
| ≥ 1 | 15 (7.9%) | 76 (20.0%) | Ref. |
| Green tea consumption (years) | |||
| 0 | 146 (76.8%) | 250 (65.8%) | 1.32 (1.30–1.34)* |
| ≤ 10 | 23 (12.1%) | 67 (17.6%) | 1.02 (0.86–1.23) |
| > 10 | 21 (11.1%) | 63 (16.6%) | Ref. |
| Fruits and vegetables intake | |||
| ≤ 14 | 48 (25.3%) | 139 (36.6%) | 0.80 (0.78–0.81)* |
| 15–20 | 51 (26.8%) | 69 (18.2%) | 1.18 (0.99–1.41) |
| ≥ 21 | 91 (47.9%) | 172 (45.2%) | Ref. |
| Exposure to cooking fumes (hours/week) | |||
| ≥ 3 | 17 (8.9%) | 16 (4.2%) | 1.64 (1.61–1.66)*** |
| 1–3 | 19 (10.0%) | 15 (4.0%) | 1.85 (1.55–2.21)*** |
| < 1 | 154 (81.1%) | 349 (91.8%) | Ref. |
| Family history of lung cancer | |||
| Yes | 15 (7.9%) | 6 (1.6%) | 2.38 (1.99–2.84)*** |
| No | 175 (92.1%) | 374 (98.4%) | Ref. |
| DNMT3B − 149 genotypes | |||
| TT | 183 (96.3%) | 345 (90.8%) | 1.62 (1.35–1.94)* |
| CT | 7 (3.7%) | 35 (9.2%) | Ref. |
| CC | 0 (0.0%) | 0 (0.0%) | |
| T allele | 373 (98.2%) | 725 (95.4%) | 1.63 (1.21–2.18)* |
| C allele | 7 (1.8%) | 35 (4.6%) | Ref. |
| Histological type | |||
| Adenocarcinoma | 108 (56.8%) | ||
| Squamous cell carcinoma | 51 (26.9%) | ||
| Othersb | 31 (16.3%) | ||
Abbreviation: N number; OR odds ratio; CI confidence interval; Ref. reference
aData were matched by age and gender
bOthers included small cell carcinoma, large cell carcinoma, mixed cell carcinoma, and unspecific malignant cell
*0.01 < p < 0.05, **0.001 < p < 0.01, ***p < 0.001