Dietary calcium intake and risk of stroke: a dose-response meta-analysis

The findings from epidemiologic studies of calcium intake and risk of stroke have been conflicting.

The objective was to conduct a dose-response meta-analysis of prospective studies to assess the association between dietary calcium intake and stroke risk.

Relevant studies were identified by searching PubMed and EMBASE databases until 11 December 2012 and by reviewing the reference lists of relevant articles. Observational prospective studies that reported RRs and 95% CIs for the association of calcium intake with stroke incidence or mortality were eligible. Study-specific RRs were combined by using a random-effects model.

Eleven prospective studies, including 9095 cases of stroke, were included in the meta-analysis. Evidence of a nonlinear association between dietary calcium intake and risk of stroke was found. In a stratified analysis, calcium intake was inversely associated with risk of stroke in populations with a low to moderate average calcium intake (<700 mg/d; RR for a 300-mg/d increase in calcium intake: 0.82; 95% CI: 0.76, 0.88) but was weakly positively associated with risk in populations with a high calcium intake (≥700 mg/d; corresponding RR: 1.03; 95% CI: 1.01, 1.06). An inverse association between calcium intake and risk of stroke was observed only in Asian populations (n = 4; RR for a 300-mg/d increase in calcium intake: 0.78; 95% CI: 0.71, 0.87).

These findings suggest that dietary calcium intake may be inversely associated with stroke in populations with low to moderate calcium intakes and in Asian populations.