Endocrine Abstracts

The need for treating vitamin D deficiency arises either when patients present with musculoskeletal symptoms attributable to hypovitaminosis D or when screening of individuals at high risk reveals the presence of vitamin D deficiency, as defined by serum 25(OH)D levels <20 ng/ml. The recommended dietary intakes of vitamin D vary with age and physiological state. The recommended daily intake ranges from 400 IU in infants, 600 IU in children and adults and 800 IU in those over 70 years of age, though higher doses varying from 1000 IU per day in infants and children to 1500–200 IU per day in adults and the elderly being required to raise 25(OH)D levels to 30 ng/ml (the level of sufficiency). The recommended dose increases 2- to 3-fold when the individual is on anti-convulsant drugs, glucocortiocids, anti fungal agents and anti-retroviral therapy.

Correction of vitamin D deficiency requires higher daily doses of vitamin D, ranging from 2000 IU for those <1 year of age, 4000 IU for children between 1–18 years of age, and 10,000 units for adults. These doses can either be delivered on a daily basis or an equivalent dose calculated and provided on weekly basis. For infants and children, both the daily dose (2000 IU /day) or a weekly calculated dose (50,000 IU per week for 6 weeks followed by 1500–200 units per day) are acceptable. In adults, the commonest strategy is to give 50,000 units per week for 8 weeks followed by 2000 IU per day or an equivalent weekly or monthly dose.

In the elderly additional anticipated benefits include fall prevention and fracture risk reduction. vitamin D therapy targeting serum 25(OH)D levels ≧ 60 nmol/l is associated with fall prevention, while levels between 66–74 nmol/l appear to be required to reduce the risk of non-vertebral and hip fractures.