The effects of metabolic conditions on prostate cancer incidence over 15 years of follow-up: results from the Olmsted County Study

What's known on the subject? and What does the study add? Previous research focusing on the role of metabolic conditions and the risk of prostate cancer is inconsistent in that it focuses on various definitions of the metabolic syndrome, a cluster of metabolic conditions that included obesity and diabetes and hypertension and does not look at the conditions alone or in combination with each other. While studies have shown an increased risk of prostate cancer in the presence of the metabolic syndrome, it is unknown whether various clusters of the conditions or the conditions themselves are differentially associated with prostate cancer risk. This study contributes to this field by investigating how these conditions are individually and in combination associated with the development of prostate cancer. Rather than just combining the conditions in to the metabolic syndrome and looking at the associated risk, we sought to identify whether the individual components were associated with prostate cancer and whether the varying combinations of them (the interactions) were differentially associated with the development of prostate cancer. OBJECTIVE center dot To determine if combinations of obesity, hypertension and diabetes influence the development of prostate cancer over 15 years of follow-up. PATIENTS AND METHODS center dot In 1990, a randomly selected cohort of Caucasian men from Olmsted County, MN, USA, aged 40-79 years, was recruited; 2445 completed a questionnaire that included physician-diagnosed diabetes and hypertension. center dot Anthropometric measures were collected during clinical examination. Biopsy-confirmed prostate cancer was identified from medical records. center dot Proportional hazards regression was used to estimate the effects of these metabolic conditions, both individually and in combination, on the incidence rate of prostate cancer. RESULTS center dot Men with hypertension alone or in combination with diabetes were more likely to develop prostate cancer than were men without any of the metabolic conditions. center dot The metabolic syndrome - the presence of all three conditions compared with men with no metabolic components - was only minimally and inversely associated with prostate cancer [hazard ratio (HR): 0.81; 95% confidence interval (CI): 0.20, 3.3] and no monotonic association between the number of metabolic components and prostate cancer was observed. CONCLUSIONS center dot Our results suggest that it may not be sufficient to treat metabolic conditions as one variable when investigating the aetiology of prostate cancer in Caucasian men. center dot Further research should focus on the separate and combined effects of these metabolic conditions in large samples.