Low Bone Mineral Density With Risk of Dementia: A Prospective Cohort Study

Area of Science:

• Gerontology
• Neurology
• Metabolic Bone Disease

Background:

• Osteoporosis and dementia frequently co-occur, yet the precise relationship between bone mineral density (BMD) and dementia risk remains incompletely understood.
• Existing research suggests a potential link, necessitating further investigation into this association.

Purpose of the Study:

• To investigate the relationship between baseline bone mineral density (BMD) and the subsequent risk of developing dementia.
• To explore potential sex-specific differences in the association between BMD and dementia incidence.

Main Methods:

• A prospective cohort study, the Hong Kong Osteoporosis Study (HKOS), included 5803 participants aged ≥40 years without dementia at baseline.
• Bone mineral density (BMD) was measured using dual-energy x-ray absorptiometry (DXA) at the lumbar spine, femoral neck, trochanter, and total hip.
• Cox proportional hazards models were employed to analyze the association between BMD and dementia incidence over a median follow-up of 16.8 years.

Main Results:

• Higher BMD T scores at the lumbar spine, trochanter, and total hip were significantly associated with a reduced risk of dementia.
• Hazard ratios for dementia risk decreased with higher BMD at these sites (e.g., HR 0.78 for trochanter BMD).
• The association between higher BMD and lower dementia risk was significant in women but not in men, and remained consistent after adjusting for serum estradiol.

Conclusions:

• Low bone mineral density (BMD) is associated with an increased risk of dementia, particularly in women.
• BMD may serve as a potential predictive marker for dementia risk.
• Further research is warranted to explore the clinical utility of BMD in dementia prediction and management strategies.