Table 1 Basic characteristics of cases and controls in Taiyuan lung cancer study
Variable | Cases | Controls | P value |
|---|---|---|---|
| Â | N (%) | N (%) | Â |
Age | Â | Â | Â |
  ≤ 45 years | 59 (14.8) | 83 (17.8) | 0.0725 |
  45 – 55 yrs | 96 (24.1) | 139 (29.8) | |
  55 – 65 yrs | 111 (27.8) | 116 (25.0) | |
  > 65 yrs | 133 (33.3) | 128 (27.4) | |
Gender | Â | Â | Â |
  Male | 202 (50.6) | 234 (50.2) | 0.9038 |
  Female | 197 (49.4) | 232 (49.8) | |
Education | Â | Â | Â |
  Illiterate | 43 (10.8) | 23 (4.9) | <.0001 |
  Primary school | 106 (26.6) | 81 (17.4) | |
  Junior middle school | 124 (31.1) | 175 (37.5) | |
  Senior middle school | 68 (17.0) | 120 (25.8) | |
  College or higher | 58 (14.5) | 67 (14.4) | |
Pack years of smoking | Â | Â | Â |
  Non smokers | 179 (44.9) | 285 (61.2) | <.0001 |
  < 20 pyrs | 39 (9.8) | 62 (13.3) | |
  20 – 40 pyrs | 64 (16.0) | 72 (15.5) | |
  ≥ 40 pyrs | 117 (29.3) | 47 (10.1) | |
Average income 10Â years ago | Â | Â | Â |
  < 1,000 yuan | 104 (26.1) | 106 (22.7) | <.0001 |
  1,000 – 2,500 yuan | 236 (59.1) | 197 (42.3) | |
  ≥ 2,500 yuan | 59 (14.8) | 163 (35.0) | |
BMI (kg/m 2 ) | Â | Â | Â |
  < 18.5 | 22 (5.8) | 9 (2.0) | <.0001 |
  18.5 – 24.9 | 250 (66.3) | 259 (56.3) | |
  25 – 29.9 | 90 (23.9) | 162 (35.2) | |
  ≥ 30 | 15 (4.0) | 30 (6.5) | |
Alcohol drinking | Â | Â | Â |
  No | 298 (74.7) | 345 (74.0) | 0.8267 |
  Yes | 101 (25.3) | 121 (26.0) | |
Tea drinking | Â | Â | Â |
  No | 242 (60.6) | 263 (56.5) | <.0001 |
  Previous drinkers | 47 (11.8) | 15 (3.2) | |
  Current drinkers | 110 (27.6) | 188 (40.3) | |
Total | 399 | 466 | Â |