Alzheimer’s Disease:
Risk Mitigation

Evidence-based prevention of Alzheimer’s disease: systematic review and meta-analysis

Twenty-one suggestions are proposed based on the consolidated evidence, with Class I suggestions targeting 19 factors: 10 with Level A strong evidence (education, cognitive activity, high body mass index in late life, hyperhomocysteinaemia, depression, stress, diabetes, head trauma, hypertension in midlife and orthostatic hypotension) and 9 with Level B weaker evidence (obesity in midlife, weight loss in late life, physical exercise, smoking, sleep, cerebrovascular disease, frailty, atrial fibrillation and vitamin C). In contrast, two interventions are not recommended: oestrogen replacement therapy (Level A2) and acetylcholinesterase inhibitors (Level B).

Yu, Jin-Tai, Wei Xu, Chen-Chen Tan, Sandrine Andrieu, John Suckling, Evangelos Evangelou, An Pan, et al. “Evidence-Based Prevention of Alzheimer’s Disease: Systematic Review and Meta-Analysis of 243 Observational Prospective Studies and 153 Randomised Controlled Trials.” Journal of Neurology, Neurosurgery & Psychiatry 91, no. 11 (November 2020): 1201–9. https://doi.org/10.1136/jnnp-2019-321913.

Exercise:
Establishing a connection between exercise and hippocampal neurogenesis, researchers turned to elucidating the biological underpinnings. One of the strongest candidates for bridging the gap between exercise and neurogenesis is Brain Derived Neurotrophic factor (BDNF), a growth factor categorized under the neurotrophin family widely expressed in the brain and throughout the rest of the central nervous system (Salehi et al., 2003).

Liu, Patrick Z., and Robin Nusslock. “Exercise-Mediated Neurogenesis in the Hippocampus via BDNF.” Frontiers in Neuroscience 12 (February 7, 2018): 52. https://doi.org/10.3389/fnins.2018.00052.

Identification of modifiable risk factors provides a crucial approach to the prevention of dementia. Nutritional or nutrient-dependent risk factors are especially important because dietary modifications or use of dietary supplements may lower the risk factor level. One such risk factor is a raised concentration of the biomarker plasma total homocysteine, which reflects the functional status of three B vitamins (folate, vitamins B12, B6).

Moderately raised plasma total homocysteine, which is common in the elderly, is one of the causes of age-related cognitive decline and dementia. Thus, the public health significance of raised plasma total homocysteine in the elderly should not be underestimated, since it is easy, inexpensive, and safe to treat with B vitamins.

Smith, A. David, Helga Refsum, Teodoro Bottiglieri, Michael Fenech, Babak Hooshmand, Andrew McCaddon, Joshua W. Miller, Irwin H. Rosenberg, and Rima Obeid. “Homocysteine and Dementia: An International Consensus Statement1.” Journal of Alzheimer’s Disease 62, no. 2 (February 20, 2018): 561–70. https://doi.org/10.3233/JAD-171042.