title: Vitamin A intake and risk of melanoma: a meta-analysis.
abstract: BACKGROUND
  Mounting evidence from experimental and animal studies suggests that vitamin A may have a protective effect on melanoma, but the findings on the association of vitamin A intake with risk of melanoma have been inconsistently reported in epidemiologic studies. We attempted to elucidate the association by performing a meta-analysis.
  
  
  METHODS
  Eligible studies were identified by searching PubMed and EMBASE databases, as well as by reviewing the references of retrieved publications. Summary odds ratios (OR) with corresponding 95% confidence interval (CI) were computed with a random-effects model. Study-specific ORs and 95% CIs for the highest vs. lowest categories of vitamin A intake were pooled.
  
  
  RESULTS
  A total of 8 case-control studies and 2 prospective studies comprising 3,328 melanoma cases and 233,295 non-case subjects were included. The summary OR for the highest compared with the lowest intake of total vitamin A, retinol and beta-carotene was 0.86 (95% CI = 0.59-1.25), 0.80 (95% CI = 0.69-0.92) and 0.87 (95%CI = 0.62-1.20), respectively. Significant heterogeneity was observed among studies on vitamin A and beta-carotene intake, but not among studies on retinol intake. Subgroup and sensitivity analyses confirmed these findings. There was no indication of publication bias.
  
  
  CONCLUSIONS
  Findings from this meta-analysis suggest that intake of retinol, rather than of total vitamin A or beta-carotene, is significantly associated with reduced risk of melanoma.
authors.affiliation: Department of Dermatology, Liaocheng People's Hospital, Liaocheng, China.
authors.forename: Yun-Ping
authors.initials: YP
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, Liaocheng People's Hospital, Liaocheng, China.
authors.forename: Rui-Xue
authors.initials: RX
authors.lastname: Chu
authors.affiliation: Department of Gynaecology and Obstetrics, Liaocheng People's Hospital, Liaocheng, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D008545:Melanoma / Q000139:chemically induced*; D011446:Prospective Studies; D012867:Skin / Q000187:drug effects; D012878:Skin Neoplasms / Q000139:chemically induced*; D014801:Vitamin A / Q000008:administration & dosage / Q000009:adverse effects*; D014815:Vitamins / Q000008:administration & dosage / Q000009:adverse effects*; D019207:beta Carotene / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D014815:Vitamins; D019207:beta Carotene; D014801:Vitamin A