title: Vitamin D intake and type 2 diabetes risk: a meta-analysis of prospective cohort studies.
abstract: BACKGROUND
  The findings form studies on the relationship between vitamin D and type 2 diabetes were inconsistent.
  
  
  OBJECTIVE
  To elucidate the association between vitamin D consumption and type 2 diabetes risk by conducting a meta-analysis.
  
  
  METHODS
  We conducted a systematic literature search to identify prospective cohort studies of vitamin D intake and type 2 diabetes risk prior to November 2012. Eligible studies were retrieved via both computer searches and manual review of references. The summary risk estimates were calculated based on the highest versus the lowest categories.
  
  
  RESULTS
  Meta-analysis of 4 prospective cohort studies involving 187, 592 participants and 9, 456 incident cases showed an absence of significant association between total vitamin D intake and type 2 diabetes risk. The combined RR was 0.93 (95% CI: 0.85-1.01). The associations were similar for subgroup analyses, a combined RR respectively was 0.94 (95% CI: 0.77-1.08), 0.91 (95% CI: 0.77-1.08), 0.93 (95% CI: 0.84-1.02), and 0.92 (95% CI: 0.84-1.01) for the intake of dietary vitamin D, supplemental vitamin D, total vitamin D in USA and total vitamin D for women only.
  
  
  CONCLUSIONS
  Our results support that there was no association between vitamin D intake and type 2 diabetes.
authors.affiliation: Department of Endocrinology, Zhongnan Hospital, Wuhan University, Wuhan, HuBei 430071, P.R. China.
authors.forename: Li-min
authors.initials: LM
authors.lastname: Zhao
authors.affiliation: Department of Endocrinology, Traditional Chinese Medicine Hospital, XinJiang Medical University, Urumqi, XinJiang 830000, P.R. China.
authors.forename: Xiao-qin
authors.initials: XQ
authors.lastname: Tian
authors.affiliation: Department of Endocrinology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, XinJiang 830011, P.R. China.
authors.forename: Jia-pu
authors.initials: JP
authors.lastname: Ge
authors.affiliation: Department of Endocrinology, Zhongnan Hospital, Wuhan University, Wuhan, HuBei 430071, P.R. China.
authors.forename: Yan-cheng
authors.initials: YC
authors.lastname: Xu
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000209:etiology*; D004032:Diet; D005260:Female; D006801:Humans; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D014807:Vitamin D
keywords: Diet; Meta-analysis; Type 2 Diabetes; Vitamin D