HIGH PREVALENCE OF VITAMIN D DEFICIENCY IN HEALTHY FEMALE MEDICAL STUDENTS IN CENTRAL SAUDI ARABIA: IMPACT OF NUTRITIONAL AND ENVIRONMENTAL FACTORS

Context. Vitamin D, a fat-soluble prohormone, is synthesized in response to sunlight and plays several roles in the body. Objectives. To determine Vitamin D status among healthy, young female medical students studying at King Saud University, Riyadh, Saudi Arabia, and to study the effects of nutritional and environmental factors on Vitamin D level. Study design. It is a prospective, observational, cross-sectional study conducted between December 2012 and March 2013. Subjects and methods. One hundred and seventy eight healthy medical students participated in the study. Each subject completed a questionnaire about vitamin D deficiency and attitude towards related environmental and nutritional factors, including duration of sunlight exposure, and vitamin D supplements. Serum levels of 25-hydroxyvitamin D, parathyroid hormone, calcium, phosphorus, and alkaline phosphatase were obtained. Results. The mean serum vitamin D level of the study group was 41.41 +/- 29.31 mmol/L (normal 75-250 mmol/L). Out of 178 participants, 126 (70.8%) were vitamin D deficient (<50 mmol/L), 29 (16.3%) had insufficient vitamin D (50-75 mmol/L), and 23 (12.9%) had normal vitamin D level (>75 mmol/L), with mean serum levels of 25.52 +/- 10.89, 62.84 +/- 7.04 and 101.41 +/- 9.1 mmol/L, respectively. In comparison between vitamin D deficient and nondeficient groups, daily milk consumption (P < 0.001), use of vitamin D supplements (P < 0.0001), and frequency of sun exposure for >= 5 days/week (P < 0.006) were significantly higher in the nondeficient group. Conclusion. Prevalence of vitamin D deficiency among female medical students in Riyadh is high and may be attributed to nutritional, social and environmental factors.