title: Calcium Intake and Cardiovascular Disease Risk: An Updated Systematic Review and Meta-analysis.
abstract: BACKGROUND
  Conflicting evidence exists regarding potential cardiovascular risks associated with high levels of calcium intake.
  
  
  OBJECTIVE
  To update and reanalyze 2 systematic reviews to examine the effects of calcium intake on cardiovascular disease (CVD) among generally healthy adults.
  
  
  METHODS
  MEDLINE; Cochrane Central Register of Controlled Trials; Scopus, including EMBASE; and previous evidence reports from English-language publications from 1966 to July 2016.
  
  
  METHODS
  Randomized trials and prospective cohort and nested case-control studies with data on dietary or supplemental intake of calcium, with or without vitamin D, and cardiovascular outcomes.
  
  
  METHODS
  Study characteristics and results extracted by 1 reviewer were confirmed by a second reviewer. Two raters independently assessed risk of bias.
  
  
  RESULTS
  Overall risk of bias was low for the 4 randomized trials (in 10 publications) and moderate for the 27 observational studies included. The trials did not find statistically significant differences in risk for CVD events or mortality between groups receiving supplements of calcium or calcium plus vitamin D and those receiving placebo. Cohort studies showed no consistent dose-response relationships between total, dietary, or supplemental calcium intake levels and cardiovascular mortality and highly inconsistent dose-response relationships between calcium intake and risks for total stroke or stroke mortality.
  
  
  CONCLUSIONS
  CVD disease outcomes were secondary end points in all trials. Dose-response metaregression analysis of cohort studies was limited by potential confounding, ecological bias, and imprecise measures of calcium exposures. Data were scarce regarding very high calcium intake-that is, beyond recommended tolerable upper intake levels.
  
  
  CONCLUSIONS
  Calcium intake within tolerable upper intake levels (2000 to 2500 mg/d) is not associated with CVD risk in generally healthy adults.
  
  
  BACKGROUND
  National Osteoporosis Foundation.
authors: From Tufts University, Boston, Massachusetts, and RAND Corporation, Santa Monica, California.
authors: Mei
authors: M
authors: Chung
authors: From Tufts University, Boston, Massachusetts, and RAND Corporation, Santa Monica, California.
authors: Alice M
authors: AM
authors: Tang
authors: From Tufts University, Boston, Massachusetts, and RAND Corporation, Santa Monica, California.
authors: Zhuxuan
authors: Z
authors: Fu
authors: From Tufts University, Boston, Massachusetts, and RAND Corporation, Santa Monica, California.
authors: Ding Ding
authors: DD
authors: Wang
authors: From Tufts University, Boston, Massachusetts, and RAND Corporation, Santa Monica, California.
authors: Sydne Jennifer
authors: SJ
authors: Newberry
mesh_terms: D002136:Calcium, Dietary / Q000008:administration & dosage / Q000009:adverse effects*; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D019587:Dietary Supplements / Q000009:adverse effects*; D006801:Humans; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology; D014807:Vitamin D / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D002136:Calcium, Dietary; D014807:Vitamin D