Vitamin D status in healthy Omani women of childbearing age. Study of female staff at the Royal Hospital, Muscat, Oman

Sunlight exposure has a vital role in vitamin D synthesis. Although vitamin D deficiency has been well documented in temperate zones, studies have been scarce in tropical countries where the population is well covered and for various reasons avoids sun exposure. The objective of this study was to investigate serum 25-hydroxyvitamin D [25[OH]D] levels and its relationship to biochemical bone profile, exposure to sunlight and vitamin D intake amongst Omani women of childbearing age. 41 apparently healthy women working at the Royal Hospital, Muscat, Oman and aged 18-45 years, with mean +/- SD of 29 +/- 6 years, were included in this study conducted in December 2006. They completed a questionnaire regarding the duration of sun exposure, food intake and type of clothing worn. Blood samples were collected from them and analyzed for serum 25[OH]D, calcium, phosphate, alkaline phosphatise and parathyroid hormone levels. All the women had a 25[OH]D level <50 nmol/L as the cut-off for deficiency. 25[OH]D levels were strongly correlated with the lack of sun exposure [r = 0.672, P < 0.001] and a significant correlation was also found between 25[OH] D level and food intake [r = 0.482, P < 0.01]. Subclinical 25[OH]D deficiency may be prevalent amongst Omani women. Risk factors such as poor sunlight exposure should be addressed in women of childbearing age and, if increased sunlight exposure is not possible, oral supplementation should be considered to avoid all the consequence and complications of vitamin D deficiency