Vitamin D deficiency is a significant global public health issue affecting all age groups. Despite the availability of sunlight in many regions and vitamin D fortification in industrialized countries, data on vitamin D status remains limited, particularly in infants, children, adolescents, and pregnant women. A systematic review of 103 studies published between 2003 and 2013 found that vitamin D deficiency is prevalent worldwide, with the highest rates observed in the Middle East, especially among girls and women. Maps of vitamin D status by age group show that low vitamin D levels are common across all age groups, with notable gaps in data for many countries in South America and Africa. Factors contributing to vitamin D deficiency include limited sun exposure, high skin melanin content, aging, and cultural practices such as skin coverage. Additionally, low dietary intake and obesity are significant contributors. The review highlights the need for more comprehensive data collection and awareness of vitamin D status in at-risk populations. The findings emphasize that vitamin D deficiency is a global public health concern, particularly in the Middle East.Vitamin D deficiency is a significant global public health issue affecting all age groups. Despite the availability of sunlight in many regions and vitamin D fortification in industrialized countries, data on vitamin D status remains limited, particularly in infants, children, adolescents, and pregnant women. A systematic review of 103 studies published between 2003 and 2013 found that vitamin D deficiency is prevalent worldwide, with the highest rates observed in the Middle East, especially among girls and women. Maps of vitamin D status by age group show that low vitamin D levels are common across all age groups, with notable gaps in data for many countries in South America and Africa. Factors contributing to vitamin D deficiency include limited sun exposure, high skin melanin content, aging, and cultural practices such as skin coverage. Additionally, low dietary intake and obesity are significant contributors. The review highlights the need for more comprehensive data collection and awareness of vitamin D status in at-risk populations. The findings emphasize that vitamin D deficiency is a global public health concern, particularly in the Middle East.