Vitamin D-An Ignored Biomarker. Should We Supplement Vitamin D in Insufficient State or Monitor It as an Important...

Objectives: Vitamin D deficiency has become a global epidemic in the past 2 decades. The present review has enlightened us about the etiopathogenesis of this epidemic. Materials and methods: A search of the literature and our previous studies were analyzed, and a conclusion was created. Results and analysis: It has been seen that the upsurge of obesity, metabolic syndrome (MetS), nonalcoholic fatty liver disease (NAFLD), and vitamin D deficiency are going hand in hand in all countries of the world. Probably downregulation of the gene Cyp2R1, whose product is 25-hydroxylase, may be the causative factor, as the enzyme 25-hydroxylase produces 25-hydroxy vitamin D from both ergocalciferol and cholecalciferol in the liver. Conclusion: Obesity, MetS, insulin resistance, and NAFLD are the causative factors of ubiquitous vitamin D deficiency.