Acetaminophen and the risk of renal and bladder cancer in the general practice research database

We conducted a nested, matched case-control study in the General Practice R esearch Database (GPRD) to assess whether acetaminophen use is associated w ith renal or bladder cancer. We matched 109 cases of renal cancer and 189 c ases of bladder cancer with up to 4 controls each by age, sex, general prac tice, duration of drug history in the GPRD, and index date. We found that u se of acetaminophen from 1 to 5 years before the index date was associated with an increased risk of renal cancer, with a direct relation between risk and number of prescriptions and an adjusted odds ratio of 2.3 (95% CI 1.0- 5.3) for subjects with 20 or more prescriptions. There was no evidence for an increase in risk of bladder cancer with acetaminophen use. We found no a ssociation between use of non-steroidal anti-inflammatory drugs and either renal or bladder cancer. These results support previous findings from our g roup and are consistent with a slight increase in the risk of renal cancer, but not bladder cancer, with heavy acetaminophen use.