Vitamin D insufficiency and deficiency are a growing concern in the reasonably sunny Eastern Mediterranean Region (EMR). Variances in the metabolism of vitamin D across populations were observed and several biological and environmental factors are reported to affect its pathways and regulatory mechanisms. Methodologies for the assessment of vitamin D indicator metabolite and threshold levels for inadequacy remain evidently controversial. This review was conducted to appraise how vitamin D status is evaluated in populations of EMR. Online databases including PubMed and Google Scholar, and websites of UN agencies and ministries of health were searched thoroughly. Surveys and cross-sectional studies conducted between 2009 and 2019 which are reporting vitamin D levels in countries of EMR were retrieved and included in this review. Surveys from Afghanistan, Iran, Iraq, Jordan, Kuwait, Oman, Pakistan, and Saudi Arabia, were included in this review. The indicator mostly reported for vitamin D status assessment was 25-hydroxyvitamin D in serum samples. Differences between countries in the cut-off levels used for assessment of vitamin D status were observed. Mostly the surveys adopted either the Institute of Medicine (IOM) or the Endocrine Society (ES) guidance, but even those showed overlap in defining insufficiency and deficiency. This discordance in cut-offs jeopardizes the credibility of results and regional and global comparability. We concluded that there is a lack of consensus on the methodologies used to assess vitamin D levels across EMR. There is an urgent need for guidance on clinical and public health practices on the assessment of vitamin D status.
Keywords: 25-hydroxyvitamin D; malpractice; supplementation; vitamin D assessment; vitamin D inadequacy.