Administration of annual oral high-dose vitamin D to community-dwelling older women in autumn and winter months increases risk of falls and fractures.

Vitamin D defi ciency is an increasingly important worldwide issue. It is estimated that one billion people worldwide have vitamin D defi ciency or insuffi ciency.1 Vitamin D defi ciency has been linked to a multitude of problems across the lifespan. The importance of vitamin D and calcium absorption has been well documented. What remains unclear is the role of vitamin D in osteoporotic fracture prevention and specifi cally, the amount and regimen of vitamin D ingestion that is safe and effective in decreasing falls and subsequent fractures.