Association between vitamin D deficiency and metabolic syndrome among adults in Arab countries

The association between vitamin D deficiency and metabolic syndrome among adults in Arab countries has not been systematically synthesised.

To assess the association between vitamin D deficiency and metabolic syndrome among adults in Arab countries.

Using guidelines from the Joanna Briggs Institute manual for evidence synthesis, meta-analysis of observational studies in epidemiology, and preferred reporting items for systematic reviews and meta-analyses, we reviewed studies published between January 2015 and January 2025 on vitamin D deficiency and metabolic syndrome among adults aged ≥ 18 years in Arab countries. Statistical analyses were conducted using R version 4.5.0; mean serum vitamin D concentrations were compared using unpaired t-tests, and the prevalence of vitamin D deficiency was compared using chi-square tests. Statistical significance was set at P ≤ 0.05.

Twelve studies involving 4399 participants from 6 Arab countries were analysed. Vitamin D deficiency was more prevalent among adults with metabolic syndrome and was associated with higher odds of metabolic syndrome (pooled odds ratio 1.84; 95% confidence interval 1.15-2.94), with substantial heterogeneity. The association remained significant after sensitivity analysis.

Given the high prevalence of vitamin D deficiency and metabolic syndrome, there is a need for preventive strategies in the Arab countries. Well-designed interventional studies are needed to clarify causality, assess the effectiveness of vitamin D interventions and determine whether there is a threshold beyond which additional increases in vitamin D provide limited metabolic benefit.