Background: The epidemiological evidence on possible relationships between coffee consumption and prostate cancer (PCa) risk by subtype of the disease (localized, advanced) and fatal PCa risk is limited.
Materials and methods: A population-based cohort of 44 613 Swedish men aged 45-79 years was followed up from January 1998 through December 2010 for incidence of localized (n = 2368), advanced (n = 918) and fatal (n = 515) PCa. We assessed the associations between coffee consumption and localized, advanced and fatal PCa risk using competing-risk regressions. We examined possible effect modification by body mass index (BMI).
Results: For localized PCa, each one cup increase in daily coffee consumption was associated with a 3% reduced risk [sub-hazard ratio (SHR) = 0.97, 95% confidence interval (CI) = 0.95-0.99]. For advanced and fatal PCa, we found a non-significant inverse association; each one cup increase was associated with a 2% reduced risk of advanced [SHR (95% CI) = 0.98 (0.95-1.02)] and fatal PCa [SHR (95% CI) = 0.98 (0.93-1.03)]. We observed evidence of effect modification by BMI for localized PCa (Pinteraction = 0.03); the inverse association was stronger among overweight and obese men (BMI ≥ 25 kg/m(2)) compared with normal-weight men (BMI < 25 kg/m(2)).
Conclusions: We observed a clear inverse association between coffee consumption and risk of localized PCa, especially among overweight and obese men.
Keywords: coffee; epidemiology; prospective cohort study; prostate cancer.