Haematological markers and prostate cancer risk: a prospective analysis in UK Biobank.

BACKGROUND: Risk factors for prostate cancer are not well understood. Red blood cell, platelet and white blood cell indices may be markers of a range of exposures that might be related to prostate cancer risk. Therefore, we examined the associations of haematological parameters with prostate cancer risk. METHODS: Complete blood count data from 209,686 male UK Biobank participants who were free from cancer at study baseline were analysed. Participants were followed-up via data linkage. After a mean follow-up of 6.8 years, 5,723 men were diagnosed with prostate cancer and 323 men died from prostate cancer. Multivariable-adjusted Cox regression was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for prostate cancer incidence and mortality by haematological parameters, and corrected for regression dilution bias. RESULTS: Higher red blood cell (HR per 1 SD increase=1.09, 95% CI 1.05-1.13) and platelet counts (HR=1.07, 1.04-1.11) were associated with an increased risk of prostate cancer. Higher mean corpuscular volume (HR=0.90, 0.87-0.93), mean corpuscular haemoglobin (HR=0.90, 0.87-0.93), mean corpuscular haemoglobin concentration (HR=0.87, 0.77-0.97) and mean sphered cell volume (HR=0.91, 0.87-0.94) were associated with a lower prostate cancer risk. Higher white blood cell (HR=1.14, 1.05-1.24) and neutrophil count (HR=1.27, 1.09-1.48) were associated with prostate cancer mortality. CONCLUSIONS: These associations of blood indices of prostate cancer risk and mortality may implicate shared common causes, including testosterone, nutrition and inflammation/infection among several others in prostate cancer development and/or progression. IMPACT: These associations provide insights into prostate cancer development and progression.