The Effects of Metabolic Disturbances on Prostate Cancer Risk and Detection.

Abstract

Prostate cancer is the most common non-cutaneous cancer and the second leading cause of cancer death among US men. Findings from previous studies suggest that metabolic conditions, including type 2 diabetes, hypertension and obesity may be associated with prostate cancer risk. As these conditions become increasingly prevalent, it is crucial to gain a better understanding how these conditions influence the risk of prostate cancer over time and how they influence prostate cancer detection. Therefore, the goal of this dissertation was to estimate the effects of type 2 diabetes, hypertension, and obesity on prostate-cancer risk and detection over 15 years of follow-up, utilizing the resources of The Olmsted County Study of Urinary Symptoms and Health Status among Men (OCS). In 1990, a randomly selected cohort of Caucasian men ages 40-79 was recruited; 2,445 completed a questionnaire that included physician-diagnosed diabetes and hypertension. Anthropometric measures were collected during clinical examination.

Biopsy-confirmed prostate cancer was identified from medical records. A 25% random subset was invited to participate in a urologic exam, during which serum prostate specific antigen levels were measured. Proportional hazards (Cox) regression was used to estimate the effects of these metabolic conditions, both individually and in combination, on the incidence rate of prostate cancer and likelihood of prostate cancer biopsy. Mixed effects linear regression was used to estimate the effects of these metabolic conditions on changes in prostate specific antigen levels and prostate volume. Type 2 diabetes, obesity and hypertension, alone and in combinations with each other were differentially associated with prostate cancer risk. Men with diabetes experienced greater age-adjusted reductions in PSA levels than did non-diabetic men. Baseline body mass index was inversely associated with the annual percent change in PSA and positively associated with the annual percent change in prostate volume. These results suggest that the presence of these metabolic conditions influences both the risk and detection of prostate cancer. Findings from these studies will set the direction for the next set of investigations to elucidate these associations and provide clues to understanding the etiology, as well as shape detection strategies in men with these metabolic conditions.