Table 3.
Main effects of DRC, cancer family history, SHS exposure, and lung cancer risk in never smokers
| Controls, n (%) | Cases, n (%) | OR* (95% CI*) | P | |
|---|---|---|---|---|
| DRC stratified at the median† | ||||
| >Median | 153 (49.8) | 88 (40.2) | ||
| <Median | 154 (50.2) | 131 (59.8) | 1.92 (1.26–2.93) | 0.0024 |
| DRC stratified by quartiles†,‡ | ||||
| Highest | 75 (24.4) | 29 (13.2) | ||
| Third | 78 (25.4) | 59 (26.9) | 1.99 (1.09-3.64) | 0.0258 |
| Second | 77 (25.1) | 60 (27.4) | 2.38 (1.21–4.70) | 0.0123 |
| First | 77 (25.1) | 71 (32.4) | 3.38 (1.81–6.32) | 0.0001 |
| Family history of any cancer§ | ||||
| No | 189 (40.2) | 103 (30.5) | ||
| Yes | 281 (59.8) | 235 (69.5) | 1.38 (1.01–1.87) | 0.043 |
| Family history of smoking-related cancer§ | ||||
| No | 346 (74.2) | 231 (69.8) | ||
| Yes | 120(25.8) | 100 (30.2) | 1.38 (0.95–2.02) | 0.092 |
| Family history of non-smoking-related cancer§ | ||||
| No | 262 (56.2) | 154 (46.5) | ||
| Yes | 204 (43.8) | 177 (53.5) | 1.45 (1.04–2.01) | 0.027 |
| Family history of lung cancer§ | ||||
| No | 407 (87.3) | 284 (85.8) | ||
| Yes | 59 (12.7) | 47 (14.2) | 1.28 (0.79–2.05) | 0.314 |
| SHS exposure | ||||
| No | 130 (30.4) | 51 (19.0) | ||
| Yes | 298(69.6) | 217 (81.0) | 1.84 (1.26–2.69) | 0.002 |
*
Adjusted for age, gender, ethnicity, dust exposure, and presence of asthma and hay fever.
†
Generalized estimating equation model with grouping by year of assay was used; DRC adjusted for the laboratory variables.
‡
P = 0.002 for the test for trend.
§
The reference group is negative family history of cancer.