Bone mineral density and the risk of incident dementia: A meta‐analysis

• Published in: Journal of the American Geriatrics Society (JAGS) Vol. 72; no. 1; pp. 194 - 200
• Main Authors: Lary, Christine W., Ghatan, Samuel, Gerety, Meghan, Hinton, Alexandra, Nagarajan, Archana, Rosen, Clifford, Ross, Ryan D., Bennett, David A., DeStefano, Anita L., Ikram, Mohammad A., Rivadeneira, Fernando, Kiel, Douglas P., Seshadri, Sudha, Beiser, Alexa
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.01.2024; Wiley Subscription Services, Inc
• Subjects: Absorptiometry, Photon; Aging; Alzheimer Disease; Alzheimer's disease; BMD; Body mass index; Bone Density; Bone Diseases, Metabolic; Bone loss; Bone mineral density; Calcaneus; Dementia; Dementia disorders; Diagnosis; Dual energy X-ray absorptiometry; Genotypes; Health risks; Humans; Longitudinal Studies; Meta-analysis; Neurodegenerative diseases; Older people; osteoporosis; BMD; dementia; osteoporosis; Alzheimer's disease; bone loss
• ISSN: 0002-8614; 1532-5415
• DOI: 10.1111/jgs.18638

Background It is not known whether bone mineral density (BMD) measured at baseline or as the rate of decline prior to baseline (prior bone loss) is a stronger predictor of incident dementia or Alzheimer's disease (AD). Methods We performed a meta‐analysis of three longitudinal studies, the Framingham Heart Study (FHS), the Rotterdam Study (RS), and the Rush Memory and Aging Project (MAP), modeling the time to diagnosis of dementia as a function of BMD measures accounting for covariates. We included individuals with one or two BMD assessments, aged ≥60 years, and free of dementia at baseline with follow‐up available. BMD was measured at the hip femoral neck using dual‐energy X‐ray absorptiometry (DXA), or at the heel calcaneus using quantitative ultrasound to calculate estimated BMD (eBMD). BMD at study baseline (“baseline BMD”) and annualized percentage change in BMD prior to baseline (“prior bone loss”) were included as continuous measures. The primary outcome was incident dementia diagnosis within 10 years of baseline, and incident AD was a secondary outcome. Baseline covariates included age, sex, body mass index, ApoE4 genotype, and education. Results The combined sample size across all three studies was 4431 with 606 incident dementia diagnoses, 498 of which were AD. A meta‐analysis of baseline BMD across three studies showed higher BMD to have a significant protective association with incident dementia with a hazard ratio of 0.47 (95% CI: 0.23–0.96; p = 0.038) per increase in g/cm2, or 0.91 (95% CI: 0.84–0.995) per standard deviation increase. We observed a significant association between prior bone loss and incident dementia with a hazard ratio of 1.30 (95% CI: 1.12–1.51; p < 0.001) per percent increase in prior bone loss only in the FHS cohort. Conclusions Baseline BMD but not prior bone loss was associated with incident dementia in a meta‐analysis across three studies.