Health Issues

PROCURE would like to thank Dr. Paul Perotte, urologist, Centre Hospitalier Université de Montréal for his contribution to this section.

Diabetes mellitus and risk of prostate cancer: a meta-analysis

Diabetologia 47(6):1071-1078, June 2004
S Bonovas, K Filioussi and A Tsantes

Study purpose: The idea of a link between diabetes and prostate cancer is controversial. Some researchers argue that men with diabetes have been shown to be at lower risk for prostate cancer. This meta-analysis from Athens, Greece pools 14 studies on the subject from 1971 to 2002. A meta-analysis is a statistical method that combines results from similar published studies in order to re-interpret all the evidence.

Study description: Five case-control studies and nine cohort studies were looked at. Case-control or retrospective studies compare a group with a disease against a similar but healthy group, and analyze their medical records and lifestyles to learn what factors may be linked with the disease. Cohort studies compare a specific outcome in groups of individuals who are alike in many ways, but differ by a certain characteristic.

Findings: Statistical calculations were used to devise an overall “pooled relative prostate cancer risk” derived from the data of the 14 studies. A slight though statistically significant link between prostate cancer and diabetes was found, but the studies’ overall “pooled relative risk” was negligible. When researchers broke down the results further, the link between prostate cancer and diabetes was shown to be inversed in the cohort and case-control studies, indicating a low and potentially lessened prostate cancer risk. However, this was statistically significant only in the cohort studies.

Conclusions: The authors assert that the findings of their meta-analysis provide strong evidence that people with diabetes experience a significant drop in risk for prostate cancer. There is biological evidence to support this view.

Epidemiologic association between prostatitis and prostate cancer

Urology 60(1):78-83, July 2002
Leslie K Dennis, Charles F Lynch and James C Turner

Study purpose: This American meta-analysis examines the link between prostate cancer and prostatitis (non-cancerous infection of the prostate) by pooling data from studies that had already examined the connection. A meta-analysis is a statistical method that combines findings from studies in order to re-interpret the overall results. Prostatitis, the infection or inflammation of the prostate, is often caused by sexually transmitted disease and can be a long-term medical condition.

Study description: A thorough search for studies and articles published through 2000 was performed. Each selected study was reviewed and its results included in the meta-analysis’ overall statistical assessment of potential increases in prostate cancer risk for men with prostatitis.

Findings: An increased prostate cancer risk of 1.6 compared to other men was seen among men with prostatitis. A jump in “relative risk estimates” for prostate cancer was also seen among men with the sexually transmitted infections gonorrhea and syphilis.

Conclusions: The authors conclude that jumps in the risk of prostate cancer along with other links to the disease suggest that infections may be one way in which prostate cancer develops.

Note: The actual causes of prostate cancer are still unclear. The authors caution that the studies looked at here may be slanted because of the use of faulty methods. Future studies must closely examine sexually transmitted infections along with other infections as potential risk factors for prostate cancer.