[A case-control study for the recognition of nonoccupational risk factors for tumors of the lower urinary tract]

A case-control study was performed to assess various nonoccupational factors (smoking, eating and drinking habits, intake of analgesics) that may be aetiological factors in the development of tumours of the lower urinary tract, while vitamins may be protective.

150 patients (125 men, mean age 66.4 years; 25 women, mean age 68.2 years) with histologically confirmed malignant tumour of bladder or other part of the lower urinary tract and a comparable group of controls, matched for age, sex and home location, were asked in a standardised personal interview about their life-long habits of smoking, eating and drinking, as well as intake of analgesics.

Smoking was the greatest risk factor. In men there was a significant positive dose-effect relationship between the number of cigarettes smoked and relative carcinoma risk, compared with nonsmokers, by a factor of 3.68 among those with the highest dosage (> 40 pack-years). Because of the small number of cases this relationship could not be proven in women, but twice as many female tumour patients than controls were smokers (8 vs 4). In men, even after adjusting for smoking, increased coffee consumption increased the risk by a factor of 2 (2-4 cups: odds ratio 2.14 [P < 0.05]; > 5 cups: odds ratio 2.22 [not significant]). An increased beer consumption had no apparent effect on the development of tumours. Findings regarding vitamin C were ambiguous. More prolonged and increased intake of phenacetin-containing analgesics in men showed a tendency towards a higher tumour risk.

Smoking cigarettes is one of the main risk factors for the development of bladder and other lower urinary tract tumours. The influence of other risk factors needs to be elucidated.