Low 25-hydroxyvitamin D and normal serum calcium concentrations in Saudi Arabia: Riyadh region.
Serum levels of the circulating form of vitamin D, 25-hydroxyvitamin D, and calcium were measured in 104 Saudis, 44 Jordanians , 17 Egyptians and 10 other subjects aged between 18 and 23 years. All subjects were male university students living in Riyadh for more than 2 years. 25-Hydroxyvitamin D levels were (mean +/- SD) 12.8 +/- 6.3, 11.0 +/- 5.8, 11.9 +/- 6.9 and 11.9 +/- 5.0 ng/ml, respectively. The percentages of subjects with serum 25-hydroxyvitamin D levels below 10 ng/ml were 35, 45, 53 and 50% for normal Saudis, Jordanians , Egyptians and others, respectively. All subjects had normal serum calcium concentrations. There was no correlation between 25-hydroxyvitamin D and serum calcium levels in the subjects investigated. This study indicates a tendency for a low vitamin D status among residents of Saudi Arabia, in spite of abundant sunlight all the year round.