Vitamin D deficiency status in Turkey: A meta-analysis

Objectives: Vitamin D deficiency is a significant public health problem in both developed and developing countries, with a reported worldwide prevalence of 30% to 80% among children and adults. The purpose of this study was to examine vitamin D deficiency/insufficiency in Turkey based on a review of the existing research.
Methods: PubMed, DergiPark, The Scientific and Technological Research Council of Turkey (TUBITAK), Google Scholar, Google, and Scopus search engines were queried. The keywords of Turkey, vitamin D, serum 25-hydroxyvitamin D, 25(OH)D3, 25(OH) vitamin D, deficiency/insufficiency of vitamin D, and prevalence were used in the screening process. The review included prospective and retrospective research studies with healthy individuals of various communities. The Newcastle-Ottawa Quality Assessment Scale was used to assess the risk of bias of the included studies.
Results: A total of 40 studies with a sample size of 111.582 were included in the meta-analysis. The prevalence of vitamin D deficiency was estimated at 63% (95% confidence interval [CI]: 58.9-66.6) for the overall population. It was observed that vitamin D deficiency has been reported as 86.6% (95% CI: 70.2-94.6) for infants, 76% (95% CI: 65.2-84.3) for pregnant women, 39.8% (95% CI: 38-41.6) for children, and 63.5% (95% CI: 58.8-67.9) for adults. The prevalence of vitamin D deficiency among women and men was identified as 64.7% (95% CI: 57.5-71.2) and 39.5% (95% CI: 31.0-48.7), respectively.
Conclusion: The results obtained in this meta-analysis revealed a high rate of vitamin D deficiency in Turkey, which varies from 58.9% to 66.6% with 95% CI. In particular, neonates, pregnant women, and adult women have a higher risk of vitamin deficiency. The results of this meta-analysis demonstrate that the vitamin D level of the Turkish public should periodically be measured and supplemented as necessary.