Association between inflammatory bowel disease and prostate cancer: A large-scale, prospective, population-based study

Background Inflammatory bowel disease (IBD) is an established risk factor for colorectal cancer. Recent reports suggesting IBD is also a risk factor for prostate cancer (PC) require further investigation. Objective To test the association between IBD with incident PC. Design, setting, and participants We studied 218,084 men in the population-based UK Biobank cohort, aged 40-69 at study entry between 2006 and 2010, with follow-up through mid-2015. Outcome measurements and statistical analysis We assessed the association between IBD and subsequent PC using multivariable Cox regression analyses, adjusting for age at assessment, ethnic group, UK region, smoking status, alcohol drinking frequency, body mass index, Townsend Deprivation Index, family history of prostate cancer, and previous prostate-specific antigen testing. Results and limitations Mean age at study entry was 56 years, 94% of the men were white, and 1.1% (n=2,311) had a diagnosis of IBD. After a median follow-up of 78 months, men with IBD had an increased risk of PC (adjusted hazards ratio [aHR] = 1.31, 95% Confidence interval [CI] = 1.03-1.67, p = 0.029). Separately analyzing the IBD subtypes of ulcerative colitis (UC) and Crohn’s disease (CD), the association with PC was only among men with the former (UC; aHR = 1.47, 95% CI = 1.11-1.95, p=0.0070), and not the latter (CD; aHR 1.06, 95% CI = 0.63-1.80, p = 0.82). Results are limited by lack of data on frequency of health care interactions. Conclusions In a large-scale, prospective cohort study, we detected an association between IBD, and UC specifically, with incident PC diagnosis. Patient summary This study of over 200,000 men in the UK suggests that men with inflammatory bowel disease may be at a higher risk of prostate cancer than the general population.