Aim
The aetiology of prostate cancer (PC) is unclear, with the few known risk factors being non-modifiable. We examined the relationships between confirmed and potential risk factors of PC diagnosis in the New South Wales (NSW) 45 and Up Study (n=267,153).
Methods
Participants were 123,732 men aged ≥45 years recruited between 2006 and 2009. Data from the 45 and Up Study were probabilistically linked with (i) NSW Cancer Registry (1994-2013) by the Centre for Health Record Linkage, and (ii) Medicare Benefits Schedule and Pharmaceutical Benefits Scheme by the Sax Institute using a unique identifier provided to the Department of Human Services, to identify reimbursements for Prostate Specific Antigen (PSA) tests and prescriptions for diabetes and urological issues. Men with history of PC, and radical prostatectomy were excluded. We used multivariable Cox regression analysis, with age as the underlying variable, to estimate adjusted hazard ratios (HRs), and multivariable Joint Cox regression to examine each association by disease spread at diagnosis.
Results
Of the 91,859 eligible men, 3701 PC cases were diagnosed between recruitment and 2013. Factors associated with PC diagnosis included family history of PC (versus none; HR=1.26; 95%CI:1.11-1.42), with an almost 2-fold increased risk for men with a father and brother with PC diagnosis (versus none; HR=1.91; 95%CI:1.35- 2.70), LUTS (versus none; HR=1.75; 95%CI:1.50-2.03), benign prostatic hyperplasia (versus none; HR=1.45; 95%CI:1.34-1.57), vasectomy (versus none; HR=1.11; 95%CI:1.03-1.20), and erectile dysfunction (versus none; HR=1.10; 95%CI:1.01-1.19). There were associations between PC diagnosis and treatments for diabetes (versus none; HR=0.73; 95%CI:0.67-0.80) and urinary complications (versus none; HR=0.84; 95%CI:0.75-0.94), with no variation in associations by disease spread at diagnosis.
Conclusion
These results support family history, urinary factors and diabetes as factors associated with PC diagnosis. The conflicting associations observed between self-reported urinary issues and prescriptions commonly used to treat these conditions, warrants further investigation.