Aim
To examine the associations between prostate cancer, diabetes and race/ethnicity.
Methods
Using administrative data from British Columbia, Canada for the period 1994 to 2012, we identified men aged ≥50 years with and without diabetes. Validated surname algorithms identified men as Chinese, Indian or of other race/ethnicity. Multivariable Cox regression was used to estimate adjusted risks of prostate cancer according to diabetes status and race/ethnicity.
Results
Our cohort of 160 566 men had a mean (sd) age of 64.7 (9.4) years and a median of 9 years’ follow‐up. The incidence rates of prostate cancer among those with and without diabetes were 177.4 (171.7–183.4) and 216.0 (209.7–222.5) per 1000 person‐years, respectively. The incidence among Chinese men was 120.9 (109.2–133.1), among Indian men it was 144.1 (122.8‐169.0) and in men of other ethnicity it was 204.8 (200.2–209.5). Diabetes was independently associated with a lower risk of prostate cancer (adjusted hazard ratio 0.82, 95% CI 0.78–0.86), as was Chinese (adjusted hazard ratio 0.54, 95% CI 0.46,0.63) and Indian (adjusted hazard ratio 0.66, 95% CI 0.49,0.89) race/ethnicity; however, there was no statistically significant interaction between diabetes status and race/ethnicity (all P>0.1).
Conclusion
Diabetes and Chinese and Indian race/ethnicity were each independently associated with a lower risk of prostate cancer.