Table 1. Characteristics of participants in lung cancer case-control study population from northern Poland.
| Variable | Lung cancer cases (N = 132) |
Controls (N = 396) |
|
|---|---|---|---|
| Sex | Women | 61 (46%) | 183 (46%) |
| Men | 71 (54%) | 213 (54%) | |
| Age | Mean, SD | 62.8 (6.2) | 62.7 (6,1) |
| Median (Min-Max) | 62.9 (48.6–77.1) | 62.9 (49.2–75.9) | |
| Pack-years of smokinga | Mean, SD | 32.2 (15.0) | 32.3 (11.1) |
| Median (Min-Max) | 30.0 (1–75) | 30.0 (7.5–80) | |
| Source of cases | Screening | 16 (12%) | |
| Incidental | 116 (88%) | ||
| Cancer subtype | Adenocarcinoma | 67 (51%) | |
| Squamous Cell Cancer | 47 (36%) | ||
| Small Cell Lung Cancer | 2 (2%) | ||
| Large Cell Carcinoma | 8 (6%) | ||
| Other | 8 (6%) | ||
| Cancer clinical stage | In situ | 1 (1%) | |
| 1a | 40 (30%) | ||
| 1b | 26 (20%) | ||
| 2a | 30 (23%) | ||
| 2b | 13 (10%) | ||
| 3a | 21 (16%) | ||
| 4 | 1 (1%) | ||
| Serum folates nmol/lb |
Median (25th-75th percentile), N |
19.3 (14.3–24.3), 132 |
17.5 (12.9–23.1), 394 |
| RBC folates nmol/l |
Median (25th-75th percentile), N |
559.7 (401.5–721.9), 93 |
506.5 (383.3–677.4), 279 |
| RBC folates corrected nmol/l |
Median (25th-75th percentile), N |
524.7 (378.4–684.4), 93 |
475.9 (367.0–642.5), 278 |
| Homocysteine μmol/l |
Median (25th-75th percentile), N |
15.7 (11.4–18.6), 129 |
14.7 (12.0–18.6), 395 |
| Supplementation | No | 87 (66%) | 268 (68%) |
| Yes | 12 (9%) | 123 (31%) | |
| No data | 33 (25%) | 5 (1%) | |
| Supplementation with B vitamins | No | 97 (73%) | 362 (91%) |
| Yes | 2 (2%) | 28 (7%) | |
| No data | 33 (25%) | 6 (2%) |
aa pack-year is defined as one pack of cigarettes smoked per day for one year.
bTwo outlying extreme values were excluded from the analyses: serum folate = 800.5; 565.4 nmol/l.