title: Calcium intake and the risk of stroke: an up-dated meta-analysis of prospective studies.
abstract: OBJECTIVE
  Calcium intake has been associated with stroke risk in a prior meta-analysis, however, newly published results are inconsistent. Dairy food benefits on stroke incidence may involve a calcium-related mechanism. We have therefore updated this meta-analysis with particular references to any possibility of a calcium-mediated dairy food risk reduction of stroke risk.
  
  
  METHODS
  We searched multiple databases and bibliographies for prospective cohort studies. Reports with multivariate-adjusted relative risk (RR) and corresponding 95% confidence intervals (CI) for the association of calcium intake with stroke incidence were considered.
  
  
  RESULTS
  Ten studies with 371,495 participants and 10,408 stroke events were analyzed. The pooled analysis showed no statistically significant association of the risk of total stroke (RR=0.96; 95% CI: 0.89-1.04) and stroke subtypes with the highest and lowest calcium intake quantiles. Nevertheless, high dairy calcium intake was significantly associated with an approximately 24% reduction of stroke risk. (RR=0.76; 95% CI: 0.66-0.86). Furthermore, a long-term follow-up (>=14 years) was helpful to reduce the risk of stroke (RR=0.67; 95% CI: 0.51-0.88). Additionally, a non-linear dose-response relationship was predicted between calcium intake and stroke risk.
  
  
  CONCLUSIONS
  Dairy calcium intake is inversely associated with stroke incidence. There is a non-linear dose-response relationship between calcium intake and stroke risk. However, when the follow-up time is long enough, the inverse relationship is independent of dose. Additional large cohort studies are required to illustrate this relationship in detail.
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China.
authors.forename: Dan-yang
authors.initials: DY
authors.lastname: Tian
authors.affiliation: Nursing School of Zhengzhou Railway Vocational and Technical College, Henan, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Tian
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China.
authors.forename: Chang-he
authors.initials: CH
authors.lastname: Shi
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Song
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ji
authors.affiliation: Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Rui-hao
authors.initials: RH
authors.lastname: Wang
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China.
authors.forename: Cheng-yuan
authors.initials: CY
authors.lastname: Mao
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China.
authors.forename: Shi-lei
authors.initials: SL
authors.lastname: Sun
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Henan, China. Email: 13903711125@126.com.
authors.forename: Yu-ming
authors.initials: YM
authors.lastname: Xu
mesh_terms: D002136:Calcium, Dietary / Q000008:administration & dosage*; D015331:Cohort Studies; D003611:Dairy Products; D004032:Diet; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000517:prevention & control
chemical_list: D002136:Calcium, Dietary