Table 2.
Odds ratios (95% confidence intervals) for bladder cancer among regular users of phenacetin and paracetamol, with adjustment for other drugs, and among exclusive users.
| Drug use | Adjusted Modela | Exclusive Use Modelb | ||||
| Controls N(%) | Cases N(%) | OR (95%CI)c | Controls N(%) | Cases N(%) | OR (95%CI)c | |
| Phenacetin | ||||||
| Never | 421 (92.3) | 313 (85.5) | 1.0 (reference) | |||
| Ever | 35 (7.7) | 53 (14.5) | 2.2 (1.3–3.8) | |||
| Duration of used | ||||||
| ≤ 4 yrs | 14 (3.1) | 22 (6.0) | 2.2 (1.0–4.7) | |||
| 4–8 yrs | 9 (2.0) | 6 (1.6) | 1.1 (0.4–3.5) | |||
| >8 yrs | 12 (2.6) | 25 (6.8) | 3.0 (1.4–6.5) | |||
| P for linear trende | 0.005 | |||||
| Paracetamol | ||||||
| Never | 398 (87.3) | 335 (91.5) | 1.0 (reference) | 249 (89.6) | 211 (90.9) | 1.0 (reference) |
| Ever | 58 (12.7) | 31 (8.5) | 0.7 (0.4–1.2) | 29 (10.4) | 21 (9.1) | 0.8 (0.5–1.6) |
| Duration of used | ||||||
| ≤ 4.5 yrs | 19 (4.2) | 12 (3.3) | 0.9 (0.4–1.9) | 12 (4.3) | 8 (3.4) | 0.8 (0.3–2.0) |
| 4.5–16 yrs | 19 (4.2) | 13 (3.6) | 0.9 (0.4–1.9) | 10 (3.6) | 9 (3.9) | 0.9 (0.4–2.5) |
| >16 yrs | 20 (4.4) | 6 (1.6) | 0.4 (0.2–1.2) | 7 (2.5) | 4 (1.7) | 0.8 (0.2–3.1) |
| P for linear trende | 0.116 | 0.672 | ||||
a Model adjusted by age, sex, number of cigarettes smoked per day, and use of other NSAIDs and analgesics
b Model adjusted by age, sex, and number of cigarettes smoked per day
c Excluded 3 subjects missing number of cigarettes smoked per day.
d Based on tertile of duration of use among controls. No medication use is referent.
e Tests for trend were performed by including a single term for categorical duration of medication use using non-users as the reference category.