title: Life course sun exposure and risk of prostate cancer: population-based nested case-control study and meta-analysis.
abstract: There is currently no means of primary prevention for prostate cancer. Increased exposure to ultraviolet-radiation may be protective, but the literature is inconclusive. We investigated associations of life course exposure to sunlight with prostate cancer. The study design was a UK-wide nested case-control study, based on 1,020 prostate specific antigen-detected cases and 5,044 matched population controls and a systematic review with meta-analysis. Men with olive/brown skin (OR = 1.47; 95% CI: 1.00 to 2.17), men who burnt rarely/never (OR = 1.11; 0.95 to 1.29) and men with the lowest levels of intense sun exposure in the 2 years prior to diagnosis (OR = 1.24; 1.03 to 1.50) had an increased prostate cancer risk. However, amongst men with prostate cancer, spending less time outside was associated with a reduced risk of advanced cancer (OR = 0.49; 0.27 to 0.89) and high Gleason grade (OR = 0.62; 0.43 to 0.91), and men who burnt rarely/never had a reduced risk of advanced cancer (OR = 0.71; 0.47 to 1.08). The meta-analysis provided weak evidence that men with the lowest (versus highest) sunlight exposure had an increased prostate cancer risk (4 studies, random-effects pooled relative risk = 1.13; 0.98 to 1.29) and higher advanced or fatal prostate cancer risk (6 studies, random-effects pooled relative risk = 1.14; 0.98 to 1.33). Our data and meta-analyses provide limited support for the hypothesis that increased exposure to sunlight may reduce prostate cancer risk. The findings warrant further investigation because of their implications for vitamin D chemoprevention trials.
authors.affiliation: Department of Social Medicine, University of Bristol, Bristol, United Kingdom. becky.gilbert@bristol.ac.uk
authors.forename: Rebecca
authors.initials: R
authors.lastname: Gilbert
authors.forename: Chris
authors.initials: C
authors.lastname: Metcalfe
authors.forename: Steven E
authors.initials: SE
authors.lastname: Oliver
authors.forename: David C
authors.initials: DC
authors.lastname: Whiteman
authors.forename: Chris
authors.initials: C
authors.lastname: Bain
authors.forename: Andy
authors.initials: A
authors.lastname: Ness
authors.forename: Jenny
authors.initials: J
authors.lastname: Donovan
authors.forename: Freddie
authors.initials: F
authors.lastname: Hamdy
authors.forename: David E
authors.initials: DE
authors.lastname: Neal
authors.forename: J Athene
authors.initials: JA
authors.lastname: Lane
authors.forename: Richard M
authors.initials: RM
authors.lastname: Martin
mesh_terms: D000367:Age Factors; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000453:epidemiology*; D012307:Risk Factors; D013472:Sunlight
chemical_list: D017430:Prostate-Specific Antigen