Optimal vitamin D status for the prevention and treatment of osteoporosis

Vitamin D3 (cholecalciferol) sufficiency is essential for maximising bone health. Vitamin D enhances intestinal absorption of calcium and phosphorus. The major source of vitamin D for both children and adults is exposure of the skin to sunlight. Season, latitude, skin pigmentation, sunscreen use, clothing and aging can dramatically influence the synthesis of vitamin D in the skin. Very few foods naturally contain vitamin D or are fortified with vitamin D. Serum 25-hydroxyvitamin D [25(OH)D; calcifediol] is the best measure of vitamin D status. Vitamin D deficiency [as defined by a serum 25(OH)D level of < 50 nmol/L (< 20 ng/mL)] is pandemic. This deficiency is very prevalent in osteoporotic patients. Vitamin D deficiency causes osteopenia, osteoporosis and osteomalacia, increasing the risk of fracture. Unlike osteoporosis, which is a painless disease, osteomalacia causes aching bone pain that is often misdiagnosed as fibromyalgia or chronic pain syndrome or is simply dismissed as depression. Vitamin D deficiency causes muscle weakness, increasing the risk of falls and fractures, and should be aggressively treated with pharmacological doses of vitamin D. Vitamin D sufficiency can be sustained by sensible sun exposure or ingesting at least 800-1000IU of vitamin D3 daily. Patients being treated for osteoporosis should be adequately supplemented with calcium and vitamin D to maximise the benefit of treatment. Vitamin D is essential for the development and maintenance of bone health from birth until death. However, while paediatricians are alert to the concern of vitamin D deficiency causing rickets in children, there is often apathy among physicians regarding, vitamin D status in adults because there are no apparent skeletal deformities as there are in rickets. Vitamin D deficiency will not only precipitate and exacerbate osteopenia and osteoporosis in both men and women, it will also cause a mineralisation defect of the skeleton and muscle weakness, all of which increase the risk of fracture. This article provides the reader with a perspective on how common vitamin D deficiency is in adults, especially post-menopausal women, and provides guidelines for the prevention and treatment of vitamin D deficiency.