Age, sex, antibiotic use, date of entry to study, and smoking in cases and controls
| Cases (n = 587) | Controls (n = 1460) | p Value | |
|---|---|---|---|
| n (%) | n (%) | ||
| p values derived by χ2 tests for categorical variables and by the Kruskal-Wallis test for comparison of continuous variables. | |||
| Age (y) | |||
| 0–20 | 79 (13) | 76 (5) | <0.001 |
| 20–40 | 207 (35) | 569 (39) | |
| 40–60 | 156 (27) | 445 (30) | |
| 60–80 | 145 (25) | 370 (25) | |
| Median | 41.64 | 43.76 | 0.003 |
| Sex | |||
| Male | 253 (43) | 642 (44) | 0.7 |
| Female | 334 (57) | 818 (56) | |
| Date of entry to study | |||
| Median | 1/10/90 | 1/03/90 | <0.001 |
| Range | 1/06/87–23/08/93 | 1/06/87–8/10/93 | |
| Smoking | |||
| Smoker | 165 (28) | 297 (20) | 0.001 |
| Non-smoker | 291 (50) | 796 (55) | |
| Unknown | 131 (22) | 367 (25) | |
| Antibiotic courses | |||
| At least one | 418 (71) | 843 (58) | <0.001 |
| Median | 2 | 1 | <0.001 |