Vitamin D and health in adults in Australia and New Zealand: a position statement

To the Editor: Our scepticism about the value of many of the burgeoning number of clinical guidelines is reinforced by the position statement on vitamin D and health for adults.1 It was surprising not to find an explicit statement that there is Level I evidence that vitamin D monotherapy does not prevent falls2 or fractures3 or reduce mortality.4 Instead, Nowson and colleagues conclude that “there is good evidence that vitamin D plus calcium supplementation effectively reduces fractures and falls in older men and women”. This statement is misleading. Vitamin D (± calcium) does not prevent falls in men.5 Co-administered calcium and vitamin D only prevents fractures in frail institutionalised older women, not in healthy community-dwelling older men or women.3

Nowson et al recommend that high-risk groups have 25-hydroxy- vitamin D levels measured, followed by appropriate vitamin D supplementation,1 applying a broad definition of high risk that probably includes most adults. Contemporaneously, a draft statement issued by the United States Preventive Services Task Force recommended against use of calcium and vitamin D (≤ 400 IU/day) for primary fracture prevention in non-institutionalised postmenopausal women.6 Similarly, a New Zealand consensus statement concluded that:

The value and clinical utility of guidelines are questionable when three groups review the same data and come to substantially different conclusions.