A CASE-CONTROL STUDY OF CANCER OF THE PROSTATE IN SOMERSET AND EAST DEVON

A case-control study in Somerset and east Devon was undertaken to inve stigate possible risk factors for prostatic cancer. A total of 159 cas es, diagnosed at Taunton, Yeovil and Exeter hospitals between May 1989 and May 1991, were identified prospectively and interviewed with a st ructured questionnaire. A total of 161 men diagnosed with benign prost atic hypertrophy and 164 non-urological hospital controls were given i dentical questionnaires. The questionnaire covered a wide range of fac tors identified from previous studies, but the central hypotheses for this study related to diet (fat and green vegetables), sexual activity and farming as an occupation. This study found no association between farming and risk of prostatic cancer (odds ratio=0.74, 95% confidence interval 0.46-1.18), nor with sexual activity as measured by number o f sexual partners (chi-squared test for trend P=0.52). A history of se xually transmitted disease was not significantly associated with prost atic cancer, but the numbers involved were very small and the odds rat io of 2.06 (0.38-11.2) is consistent with the hypothesis. A range of q uestions aimed at eliciting dietary fat intake produced no significant associations, although meat consumption showed increasing risk with i ncreasing consumption (test for trend P=0.005). Increased consumption of leafy green vegetables was associated with lower risk, but not sign ificantly so (test for trend P=0.16). As expected with so many factors investigated, some statistically significant associations were found, although these can only be viewed as hypothesis generating in this co ntext. These included apparent protective effects of circumcision and high fish consumption.