Sexual behaviour, history of sexually transmitted diseases, and the risk of prostate cancer:: a case-control study in Cuba

Background The relationship between the risk of prostate cancer and sexual activity and history of sexually transmitted diseases was investigated in a case-control study conducted in Cuba aimed at assessing the effect of lifestyle and environmental factors, as well as hormonal and genetic factors, on the occurrence of this disease. Methods During the period 1998-2000, all men up to 84 yr old with newly diagnosed, cytologically and/or histologically confirmed prostatic cancer who were resident in Havana City were identified in nine major hospitals in the area. Controls were resident in the same city, frequency-matched by age (+/-5 years) and hospital. The study included 273 cases and 254 controls. Information was obtained through an interview. Results The risk of prostate cancer was increased among men with a history of venereal disease (odds ratio = 1.7, 95% CI = 1.1-2.5). A higher frequency of cases reported having had sex with prostitutes, although the estimate of relative risk did not reach statistical significance. Similarly, a nonsignificant positive association was found with the number of female sexual partners. A significant increased risk was observed in subjects who reported having sexual intercourse more than 7 times per week compared with those who reported a weekly frequency of 3 times or fewer (odds ratio = 2.1, 95% CI = 1.2-3.7). Moreover, a significant trend was demonstrated. Conclusions The study supports the hypothesis that an infectious factor related to sexual behaviour could be involved in the occurrence of prostate cancer. A role for hormonal factors related to sexual activity cannot be ruled out.