Vitamin D deficiency is common in the elderly and contributes to the increased incidence of falls, hip fracture and depression in this population. An unknown number of elderly have vitamin D resistance resulting in a functional vitamin D deficiency state. Because there are no simple procedures or blood tests that identify vitamin D resistance, its prevalence and contribution to disability in the elderly is unknown. Our inability to screen for this condition precludes our ability to initiate and monitor treatment.

Previous studies indicate that fingernail thickness correlates with vitamin D status and may therefore provide a simple cost effective procedure to not only identify patients with vitamin D deficiency but also, those with vitamin D resistance. This procedure may also provide a way to monitor an individual's response to treatment.

This study is designed to demonstrate the association between fingernail thickness and vitamin D status.