title: Effect of calcium or vitamin D supplementation on vascular outcomes: a meta-analysis of randomized controlled trials.
abstract: BACKGROUND
  Whether calcium or vitamin D supplementation reduces serious vascular outcomes in older people remains unclear. We conducted a meta-analysis based on randomized controlled trials to evaluate the effect of calcium or vitamin D supplementation on the risk of major cardiovascular outcomes.
  
  
  METHODS
  We performed electronic searches in PubMed, Embase, and the Cochrane Library to identify relevant randomized controlled trials. Odds ratios (ORs) were used to measure the effect of calcium or vitamin D supplementation on the risk of major vascular outcomes with a random-effect model.
  
  
  RESULTS
  Of the 1643 identified studies, we included 11 trials reporting data on 50,252 individuals. These studies reported 2685 major cardiovascular events, 1097 events of myocardial infarction, and 1350 events of stroke. Calcium or vitamin D supplementation did not have an effect on major cardiovascular events (OR, 1.03; 95% confidence interval [CI]: 0.94-1.12; P=0.54), myocardial infarction (OR, 1.08; 95% CI: 0.96-1.22; P=0.21), or stroke (OR, 1.01; 95% CI: 0.91-1.13; P=0.80) when compared to the effect with a placebo. Subgroup analysis indicated that calcium supplementation alone might play an important role in increasing the risk of major cardiovascular events, myocardial infarction, and stroke, but this difference could not be identified as statistically significant. Furthermore, males seem to experience more harmful effects with supplements of calcium or vitamin D than the effects experienced by females.
  
  
  CONCLUSIONS
  Calcium supplementation might increase the risk of major cardiovascular events, myocardial infarction, and stroke compared to the risk with a placebo.
authors.affiliation: Department of VIP Special Clinic, Shanghai Seventh People's Hospital, Shanghai, China.
authors.forename: Pei-Juan
authors.initials: PJ
authors.lastname: Mao
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.forename: Lan
authors.initials: L
authors.lastname: Tang
authors.forename: Yu-Qiong
authors.initials: YQ
authors.lastname: Xian
authors.forename: Yan-Song
authors.initials: YS
authors.lastname: Li
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Wang
authors.forename: Xiu-Hua
authors.initials: XH
authors.lastname: Zhu
authors.forename: Hua-Li
authors.initials: HL
authors.lastname: Qiu
authors.forename: Jia
authors.initials: J
authors.lastname: He
authors.forename: Yu-Hao
authors.initials: YH
authors.lastname: Zhou
mesh_terms: D000368:Aged; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology* / Q000517:prevention & control; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D016896:Treatment Outcome; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood
chemical_list: D002136:Calcium, Dietary; D014807:Vitamin D
keywords: Calcium; Meta-analysis; Myocardial infarction; Stroke; Vitamin D