Osteoporosis is defined as a skeletal disorder with compromised bone strength that increases the risk of fracture.6 Although osteoporosis and AD are two distinct diseases, several risk factors are shared between them, such as alcohol consumption and smoking.8,9 The association between AD and osteoporosis concerns both bone density and bone quality.6 Decline in bone quality often results in fragility fractures, which are fractures due to a fall from standing height or less.6 In most cases, this does not cause fractures, suggesting that skeletal abnormalities in AD may be more than loss of bone density.6
Bone mineral density values measured by dual-energy X-ray absorptiometry, and cerebral volume measured by magnetic resonance imaging, are biomarkers for measuring mineral loss in the bone and neuronal loss in the brain, respectively.6,10 Bone mineral density and cognitive function are found to be correlated, suggesting a parallel course for AD and osteoporosis.6 It is proposed that the coexistence of AD and osteoporosis occurs from shared aetiologies rather than a causal relationship between the two diseases.6
References:
1.Jeon JH, Park JH, Oh C, et al. Dementia is associated with an increased risk of hip fractures: a nationwide analysis in Korea. J Clin Neurol 2019; 15 (2): 243–249.
2.Jeong SH, Lee HJ, Kim SH, et al. Effect of dementia on all-cause mortality in hip fracture surgery: a retrospective study on a nationwide Korean cohort. BMJ Open 2023; 13 (5): e069579.
3.Zhang M, Hu S, Sun X. Alzheimer’s disease and impaired bone microarchitecture, regeneration and potential genetic links. Life (Basel) 2023; 13 (2): 373.
4.Kwon MJ, Kim JH , Kim JH, et al. The occurrence of Alzheimer’s disease and Parkinson’s disease in individuals with osteoporosis: a longitudinal follow-up study using a national health screening database in Korea. Front Aging Neurosci 2021; 13: 786337.
5.Xiao T, Ghatan S, Mooldijk SS, et al. Association of bone mineral density and dementia: the Rotterdam study. Neurology 2023; 100 (20): e2125–e2133.
6.Chen YH, Lo RY. Alzheimer’s disease and osteoporosis. Tzuchi Med J 2017; 29 (3): 138–142.
7.Zhang L, Wang J, Dove A, et al. Injurious falls before, during and after dementia diagnosis: a population-based study. Age Ageing 2022; 51 (12): afac299.
8.Papaioannou A, Kennedy CC, Cranney A, et al. Risk factors for low BMD in healthy men age 50 years or older: a systematic review. Osteoporos Int 2009; 20 (4): 507–518.
9.Cataldo JK, Prochaska JJ, Glantz SA. Cigarette smoking is a risk factor for Alzheimer’s disease: an analysis controlling for tobacco industry affiliation. J Alzheimers Dis 2010; 19 (2): 465–480.
10.Loskutova N, Honea RA, Vidoni ED, et al. Bone density and brain atrophy in early Alzheimer’s disease. J Alzheimers Dis 2009; 18 (4): 777–785.
