Smoking and prostate cancer: Findings from an Australian case-control study

Background:To examine the risk of smoking onhistopathologically-confirmed moderate- and high-grade prostatecancer.Materials and methods:A population-based case-control studywas conducted in Melbourne, Sydney and Perth between 1994 and 1998 inmen aged below 70 years. Cases were recruited from cancer registries andcontrols were selected from electoral registers. 1498 cases and 1434controls were interviewed and a detailed smoking history obtained. Datawere analyzed by unconditional logistic regression, adjusting for age,study center, year of recruitment, family history and country ofbirth.Results:The odds ratios (OR) were 1.02 (0.85–1.22)for former smoking and 0.82 (0.65–1.05) for current smoking.The respective ORs were 0.95 (0.78–1.15) and 0.76(0.59–0.99) for moderate grade tumors, and 1.28 (0.96–1.70)and 1.00 (0.67–1.47) for high-grade tumors (P = 0.2for test that ORs of the two grades were identical). There was noevidence of a dose-response effect for duration of smoking, amountsmoked daily, pack-years of smoking and years since quitting and mostORs for these variables were close to unity.Conclusions:Smoking was not associated with the incidenceof prostate cancer. The widths and upper limits of the confidenceintervals for the effects of current and former smoking were consistentwith weak effects at most.