title: Dietary calcium intake and mortality risk from cardiovascular disease and all causes: a meta-analysis of prospective cohort studies.
abstract: BACKGROUND
  Considerable controversy exists regarding the association between dietary calcium intake and risk of mortality from cardiovascular disease and all causes. Therefore, we performed a meta-analysis of prospective cohort studies to examine the controversy.
  
  
  METHODS
  We identified relevant studies by searching MEDLINE, Embase, and the Cochrane Library databases between 1 September 2013 and 30 December 2013. Reference lists of relevant articles were also reviewed. Observational prospective studies that reported relative risks and 95% confidence intervals for the association of calcium intake with cardiovascular and all-cause mortality were eligible. Study-specific relative risks were pooled using a random-effects model.
  
  
  RESULTS
  In this meta-analysis, 11 prospective studies with 12 independent cohorts, involving 757,304 participants, were eligible. There was evidence of a non-linear association between dietary calcium intake and risk of mortality from cardiovascular disease (P for non-linearity <0.01) and all causes (P for non-linearity <0.01). A dose-response analysis showed a U-shaped relationship between dietary calcium intake and cardiovascular mortality. Intakes that were lower and higher than around 800 mg/day were gradually associated with a higher risk of cardiovascular mortality. For all-cause mortality, we also observed a threshold effect at intakes around 900 mg/day. The risk of all-cause mortality did not decrease further at intakes above 900 mg/day.
  
  
  CONCLUSIONS
  This meta-analysis of prospective cohort studies suggests that dietary calcium intake is associated with cardiovascular mortality in a U-shaped manner and that high dietary calcium intake (>900 mg/day) is not associated with a decreased risk of all-cause mortality.
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.forename: Hongxia
authors.initials: H
authors.lastname: Chen
authors.forename: Yingying
authors.initials: Y
authors.lastname: Ouyang
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, China. drwbao@hotmail.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Bao
authors.forename: Maosheng
authors.initials: M
authors.lastname: Yan
mesh_terms: D000328:Adult; D002136:Calcium, Dietary / Q000008:administration & dosage*; D002318:Cardiovascular Diseases / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D040242:Risk Reduction Behavior
chemical_list: D002136:Calcium, Dietary