Effect of declining renal function on bone density in aging women.

Area of Science:

• Gerontology
• Nephrology
• Endocrinology

Background:

• Trabecular bone loss is a significant concern in aging women, with multifactorial causes.
• The role of declining renal function in age-related bone loss remains incompletely understood.
• Subtle decreases in kidney function may be masked by normal serum creatinine levels in older adults.

Purpose of the Study:

• To investigate the association between declining renal function and trabecular bone loss in postmenopausal women.
• To determine if renal insufficiency contributes to bone density reduction in aging women.
• To explore the potential mediating roles of 1,25-dihydroxyvitamin D and parathyroid hormone.

Main Methods:

• Studied 19 postmenopausal Caucasian women (average age 67) with varying years since menopause.
• Quantitated trabecular bone density using computerized tomography of the spine.
• Assessed renal function via serum creatinine, creatinine clearance, and measured 1,25-dihydroxyvitamin D and parathyroid hormone levels.

Main Results:

• Creatinine clearance decreased with age and was inversely related to serum creatinine.
• Bone density declined with age, and this correlation weakened when controlling for creatinine clearance.
• Bone density was inversely proportional to creatinine clearance, with this relationship attenuated by 1,25-dihydroxyvitamin D and parathyroid hormone levels.

Conclusions:

• Occult renal insufficiency may contribute to trabecular bone loss in aging women.
• The bone loss associated with renal insufficiency may be partly mediated by alterations in 1,25-dihydroxyvitamin D and parathyroid hormone.
• Creatinine clearance is a more sensitive indicator of renal function than serum creatinine in this population for assessing bone loss risk.