Although vitamin D does little to impact bone density per se, the 2014 American Geriatrics Society (AGS) Consensus Statement on Vitamin D for the Prevention of Falls emphasizes the importance of assuring elderly patients have adequate vitamin D to prevent falls and fractures that often have devastating sequelae. Loss of bone strength and muscle weakness have been linked to low vitamin D levels and may contribute to falls that lead to injuries such as hip fractures that often lead to early death. Along with the AGS, the Endocrine Society and the International Osteoporosis Foundation all agree that vitamin D [25(OH)D] levels of at least 30 ng/mL should provide the benefit needed for older adults. Measurement of vitamin D levels is specifically endorsed for patients who are obese, on certain medications that interfere with the absorption of vitamin D (e.g., bile acid sequestrants and cytochrome P450 inducers such as phenobarbital, etc.), or those who have malabsorption syndromes.
Reference: American Geriatrics Society Workgroup on Vitamin D Supplementation for Older Adults. Recommendations abstracted from the American Geriatrics Society Consensus Statement on vitamin D for prevention of falls and their consequences. J Am Geriatrics Soc 2014;62:147-152.