Objective: Observational studies have associated diabetes with a decreased risk of prostate cancer. We aimed to evaluate this association using the General Practitioner Research Database in the UK.
Methods: Population based case-control study nested in a cohort.
Results: We identified 2,183 incident cases of prostate cancer between January 1995 and December 2001. We found that diabetic patients had a decreased risk of prostate cancer (OR = 0.72; 95% CI: 0.59-0.87). This association was observed among treated diabetics (OR = 0.63; 95% CI: 0.50-0.80) but not among untreated diabetics (OR = 1.01; 95% CI: 0.73-1.40). Our results suggest that the observed reduced risk could be restricted to users of insulin or sulphonylureas.
Conclusion: Patients with diabetes have a decreased risk of prostate cancer. The role of antidiabetic treatment in this association warrants further research.