title: Vitamin D and cancer mortality: systematic review of prospective epidemiological studies.
abstract: Accumulating evidence from experimental and epidemiological studies suggests that vitamin D deficiency might be a causal risk factor for cancer and therewith associated mortality. We performed a systematic review in Medline up to February 2012 to identify prospective studies on 25-hydroxyvitamin D (25[OH]D) and cancer mortality as well as on 25(OH)D and survival in cancer patients. Our search retrieved 13 studies on cancer-specific mortality and 20 studies on overall mortality in cancer patients. Data on 25(OH)D and cancer mortality were mainly derived from general populations. The results were inconsistent and yielded either no, inverse or positive associations. By contrast, the majority of studies in cancer patients showed that patients with higher 25(OH)D levels had a decreased risk of mortality. This relationship was particularly evident in cohorts of colorectal cancer patients. In contrast, there was no indication for increased mortality risk with higher vitamin D levels in any cancer cohort. In conclusion, the relationship of vitamin D status and cancerspecific mortality is still unclear and warrants further studies. Our results provide a strong rationale to perform prospective randomized controlled studies to document a potential effect of vitamin D supplementation on survival in cancer patients.
authors.affiliation: Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands. stefan.pilz@meduni-graz.at
authors.forename: Stefan
authors.initials: S
authors.lastname: Pilz
authors.forename: Katharina
authors.initials: K
authors.lastname: Kienreich
authors.forename: Andreas
authors.initials: A
authors.lastname: Tomaschitz
authors.forename: Eberhard
authors.initials: E
authors.lastname: Ritz
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lerchbaum
authors.forename: Barbara
authors.initials: B
authors.lastname: Obermayer-Pietsch
authors.forename: Veronika
authors.initials: V
authors.lastname: Matzi
authors.forename: Joerg
authors.initials: J
authors.lastname: Lindenmann
authors.forename: Winfried
authors.initials: W
authors.lastname: März
authors.forename: Sara
authors.initials: S
authors.lastname: Gandini
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Dekker
mesh_terms: D006801:Humans; D009369:Neoplasms / Q000453:epidemiology / Q000401:mortality*; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D