Does radiolabelled diphosphonate retention reflect bone metabolism in the elderly?

Area of Science:

• Gerontology
• Bone Metabolism
• Pharmacokinetics

Background:

• Whole-body retention of diphosphonates (WBR) is a validated indicator of bone metabolism in younger populations.
• The utility and interpretation of WBR in elderly individuals remain less understood.
• Age-related changes in renal function can influence drug retention and metabolism.

Purpose of the Study:

• To investigate the 24-hour whole-body retention of diphosphonates (WBR) in an elderly cohort.
• To determine the correlation between WBR, chronological age, and renal function in older adults.
• To assess the clinical applicability of WBR measurements in the elderly.

Main Methods:

• Twenty-seven elderly subjects (19 community-dwelling, 8 inpatients) underwent 24-hour WBR measurement.
• Statistical analysis was performed to assess correlations between WBR, age, and renal function.
• A subset of subjects received vitamin D supplementation to observe its effect on WBR.

Main Results:

• WBR demonstrated a significant positive correlation with increasing age (r = 0.55, P < 0.01).
• WBR showed a significant negative correlation with renal function (r = -0.60, P < 0.01).
• Vitamin D supplementation did not lead to a decrease in WBR in the observed subjects.

Conclusions:

• Elderly individuals exhibit increased WBR with advancing age, potentially due to diminished renal function.
• Accurate assessment of renal function is crucial for interpreting WBR measurements in the elderly.
• The clinical utility of WBR in older populations is limited without considering confounding factors like renal impairment.