Dietary Calcium or Vitamin D Intake and Type 2 Diabetes Mellitus Incidence: A Dose-Response Meta-analysis

Background: Dietary Calcium and vitamin D intake may have effects on the onset risk of type 2 diabetes mellitus (T2DM), whereas the results of existing studies are inconsistent. We performed a meta-analysis of prospective studies to evaluate the association between dietary calcium orvitamin D intakeand the onset risk of T2DM. Methods: We searched PubMed, Web of Science, and Embase for relevant studies published through 5 Jan 2021. The relative risks (RRs) with 95% confidence intervals (CIs) of T2DM in relation to dietary calcium and vitamin D intake were pooled with a fix or random-effects model. Results: 22 cohort studies were included in this meta-analysis, which comprising 31027 cases and 448578 participants. We found dietary calcium (RR: 0.84; 95% CI: 0.76–0.93) rather than dietary vitamin D (RR: 1.00; 95% CI: 0.92–1.08) reduced the onset risk of T2DM. Subgroup analysis showed the efficacy of dietary calcium intake is only in Asian, women and older population. Dose-response analysis revealed that each 300 mg/day increase in dietary calcium intake reduces the risk of T2DM by 8%. However, the increasing dietary vitamin D intake does not affect the risk of T2DM. Conclusions: Dietary calcium intake reduces the onset risk of T2DM but dietary vitamin D has no effect.