The roles of ultraviolet-B irradiance, vitamin D, apolipoprotein E ε4, and diet in the risk of prostate cancer

Excerpt

There have been a number of papers investigating the risk-modifying factors for prostate cancer, with diet, ultraviolet-B (UVB), and genetics among the leading factors considered, but there is still no agreement on the relative contribution of these factors. For example, the paper by Barnett et al. [1] found no link in their recent study between prediagnostic serum 25-hydroxyvitamin D [25(OH)D] and prostate cancer incidence in older men during a mean 5.3-year follow-up period [1]. This finding agrees with those of other recent reviews [2‐4]. However, studies looking at prostate cancer incidence with respect to personal UVB irradiance ([5] and Refs. 31–33 in [1]) offer some of the more convincing evidence for a role of UVB and vitamin D in reducing the risk of prostate cancer. These studies were based on early-life and/or long-term UVB irradiance, and prostate cancer is a type of cancer that progresses very slowly. There is also good evidence that vitamin D improves survival for those diagnosed with prostate cancer (Refs. 34 and 35 in [1]). Thus, vitamin D appears to be important in reducing the risk of prostate cancer over many years, so measuring 25(OH)D levels shortly before diagnosis of prostate cancer may not provide an accurate indication of the overall effect of vitamin D on prostate cancer risk. …