Vitamin D and bone health in the elderly

Area of Science:

• Gerontology
• Nutritional Science
• Bone Metabolism

Background:

• Vitamin D nutrition relies on sun synthesis and dietary intake.
• Reduced sun exposure in Europe leads to age-related vitamin D decline and deficiency in the elderly.
• US milk fortification and supplement use result in higher dietary vitamin D intake, but stores may still fall with age.

Purpose of the Study:

• To examine the factors influencing vitamin D status in aging populations.
• To identify at-risk groups for vitamin D deficiency and recommend intake levels.
• To discuss the clinical implications of vitamin D deficiency and excess.

Main Methods:

• Review of existing literature on vitamin D synthesis, metabolism, and requirements.
• Analysis of dietary intake patterns and sun exposure in European and US populations.
• Assessment of the relationship between vitamin D status and age-related bone diseases.

Main Results:

• Vitamin D stores generally decrease with age, increasing deficiency risk in the elderly, particularly the institutionalized.
• Recommended total vitamin D intake for the elderly is 15-20 micrograms/day (600-800 IU).
• Subclinical deficiency may contribute to hip fractures; severe deficiency causes osteomalacia.

Conclusions:

• Elderly individuals, especially the housebound or those with malabsorption, require careful attention to vitamin D intake.
• While severe deficiency is less common in the US, subclinical deficiency's role in hip fractures needs further research.
• Recommended vitamin D intake is generally safe, with risks of toxicity (hypercalcemia) at very high doses (>1000 micrograms/day).