Megadose therapy for vitamin D deficiency.

he international perception of bronzed Australians inhabiting a " sunburnt country " is under threat. Most Australians, including children, now sensibly avoid excessive sun exposure to reduce the risk of skin cancer. However, other Australians, particularly those who are older, disabled or institutionalised often do not receive even modest levels of sunlight exposure. This has led to the paradox of vitamin D deficiency emerging as a public health issue in sunny Australia. Besides older and institutionalised Australians, others particularly at risk of vitamin D deficiency are people with pigmented skin from Africa, India and Pakistan; women who practise veiling; those on certain medications (eg, anti-epileptic drugs); and those with malabsorption or a low vitamin D intake. Even young Australians, pregnant women and their infants are at risk of this emerging health problem. 1 The prevalence of vitamin D deficiency among Indigenous Australians has not been determined, but is likely to be high. The problem was highlighted recently in the Journal in a position statement on vitamin D and bone health in adults. 2 Vitamin D deficiency is usually classified as mild (25-hydroxyvita-min D [25OHD] level, 25–49 nmol/L), moderate (12.5–24 nmol/L) or severe (< 12.5 nmol/L). The Geelong Osteoporosis Study detected mild or moderate deficiency in more than one in three women surveyed in summer, which rose to one in two in winter. 3 Even in southeast Queensland, Western Australia, New South Wales and Victoria, nearly a third of men and women have mild to moderate vitamin D deficiency. 4 Almost half of nursing home patients, and almost all patients in aged care facilities surveyed have at least mild vitamin D deficiency. Thus, despite Australia being a " sunburnt country " , vitamin D deficiency is common. But why is it important? Severe vitamin D deficiency results in osteomalacia in adults and rickets in children. Milder vitamin D deficiency results in secondary hyperparathyroidism and increased bone turnover, predispos-ing to osteoporosis. Proximal myopathy and muscle pains may occur in moderate or severe vitamin D deficiency, and the incidence of falls is increased. 5 Less well known is the impact of vitamin D deficiency on depression, immunity and autoimmunity, obesity, and the progression of type 2 diabetes mellitus. It is also important to correct vitamin D deficiency to optimise the effects of other anti-osteoporotic drugs. In a recent United States study of 1536 women receiving anti-osteoporotic therapy, 52% had vitamin D deficiency. 6 …