A study by Australian scientists has found that women who wear veils for religious or cultural reasons may not be getting enough vitamin D.
Vitamin D is essential for healthy bones and the best and most natural source of vitamin D is sunlight.
The researchers say there are adult exposure recommendations to prevent vitamin D deficiency, but because 95% of skin cancers and 99% of melanomas in Australia are due to sun exposure, it is difficult to make similar recommendations for children, also as skin pigmentation increases, so too does the period of exposure to UVB required to synthesise adequate amounts of vitamin D.
Scientists from the Children's Hospital at Westmead, conducted a study of 149 North African refugees living in south-western Sydney as part of a health screening programme, and found only two of them had sufficient levels of vitamin D and despite a significant increase in sunshine over the study period, most participants remained vitamin D deficient at the end of summer.
The scientists say though it is easily prevented and treated, simple vitamin D deficiency-related rickets and osteomalacia have made a global resurgence - risk factors for vitamin D deficiency include dark skin pigmentation, cultural practices such as veiling and covering, insufficient exposure to sunlight, and exclusive breastfeeding beyond 6-12 months for at-risk groups.
Simple vitamin D deficiency can cause bone pain, myalgia, myopathy, increased risk of falls, osteoporosis and hip fractures in adults and in children ,whose mothers also usually vitamin D deficiency, it causes seizures, rickets, bowed limbs, fractures and motor delay.
The researchers say vitamin D is not only important for the bones but also for the immune system and cell growth.
The study was conducted in Sydney in the winter and spring of 2006, and follow-up research, after the following summer, showed a slight increase in vitamin D levels but almost 90% of those tested were still deficient.
The researchers say that dark-skinned or veiled infants, children and adults need additional sunlight to synthesise the amount of vitamin D and screening should be carried out for simple vitamin D deficiency in the first trimester of pregnancy for dark-skinned or veiled women;
They recommend vitamin D supplementation (400 IU daily) in breastfed infants of dark-skinned or veiled women until 12 months of age; and preventive daily 400 IU vitamin D supplementation in at-risk groups.
Dr Munns says these people should have their vitamin D levels checked annually.
The study participants were from Sudan, Egypt and Kenya, and all had very dark skin - however it was found that adherence to recommended vitamin D therapy was poor even in those referred directly to hospital and the researchers say this is common in refugee populations.
The study is published in the Medical Journal of Australia.