Chapter 1
Understanding the global challenge and the path to a unified solution
Alzheimer's disease (AD) represents one of the most significant public health challenges of the 21st century. As the world's population ages, the prevalence of this devastating neurodegenerative disorder continues to rise at an alarming rate. Understanding the scope and impact of AD is essential for appreciating why standardized approaches to treatment and assessment are not merely beneficial but absolutely necessary.
The World Health Organization has declared dementia a global public health priority. Alzheimer's disease, which accounts for approximately 60-70% of all dementia cases, disproportionately affects older adults but can also manifest in younger individuals through early-onset forms. The disease not only devastates the individuals affected but also places enormous burdens on families, caregivers, healthcare systems, and economies worldwide.
The burden of AD is unevenly distributed across the globe, with significant variations in prevalence, diagnosis rates, and access to treatment:
| Region | Cases (millions) | % of Global Total | Growth Rate |
|---|---|---|---|
| Asia Pacific | 23.6 | 43% | +4.1%/year |
| Europe | 10.2 | 18% | +1.8%/year |
| Americas | 10.7 | 19% | +2.3%/year |
| Africa | 4.0 | 7% | +3.8%/year |
| Middle East | 3.5 | 6% | +3.5%/year |
Alzheimer's disease is characterized by a complex interplay of pathological processes that ultimately lead to progressive neurodegeneration and cognitive decline. Understanding these mechanisms is crucial for developing effective treatments and for appreciating why the NAD+ homeostasis approach represents such a significant advancement.
For decades, the amyloid hypothesis has dominated AD research. This theory proposes that the accumulation of amyloid-beta (Aβ) peptides in the brain triggers a cascade of events leading to neuronal death. Key aspects include:
The tau hypothesis focuses on the hyperphosphorylation and aggregation of tau protein:
While amyloid and tau pathologies have been the primary focus of AD research, emerging evidence from 2024-2025 studies reveals that metabolic dysfunction, particularly NAD+ depletion, may be an upstream driver of these pathological cascades. This metabolic perspective forms the foundation of the WIA-ALZHEIMERS standard.
Chronic inflammation in the brain plays a significant role in AD progression:
Mitochondrial abnormalities are increasingly recognized as central to AD pathogenesis:
Alzheimer's disease progresses through distinct stages, though the boundaries between stages are often blurred in clinical practice. Understanding this continuum is essential for appropriate intervention timing:
Pathological changes begin in the brain, including amyloid accumulation, but no clinical symptoms are present. NAD+ levels begin to decline. This is the optimal window for preventive interventions.
Individuals notice subtle changes in their cognitive abilities, but standardized tests remain normal. NAD+ levels are reduced by approximately 15-20%.
Objective cognitive deficits are measurable, but daily functioning remains largely intact. NAD+ levels are reduced by 25-35%. This stage represents a critical intervention opportunity.
Cognitive decline affects daily activities. Memory, language, and executive function are impaired. NAD+ levels are reduced by 35-40%.
Significant functional impairment requiring assistance with daily activities. Behavioral changes become prominent. NAD+ levels are reduced by 40-45%.
Near-complete dependence on caregivers. Communication is severely limited. NAD+ levels are critically depleted.
| Factor | Impact | Notes |
|---|---|---|
| Age | Risk doubles every 5 years after 65 | Strongest risk factor |
| APOE ε4 allele | 3-12x increased risk | One copy: 3x; Two copies: 12x |
| Family history | 2-3x increased risk | First-degree relative with AD |
| Female sex | ~2/3 of AD patients are women | Possibly hormonal factors |
| Down syndrome | Nearly universal AD by age 40 | Extra copy of APP gene |
The Lancet Commission on Dementia (2024 update) identified 14 modifiable risk factors that together account for approximately 45% of dementia cases:
Many of these modifiable risk factors share a common thread: they all impact NAD+ metabolism. Physical inactivity, obesity, and diabetes all reduce NAD+ levels, while exercise and caloric restriction increase NAD+ through activation of NAMPT, the rate-limiting enzyme in NAD+ biosynthesis. This convergence supports the NAD+ homeostasis hypothesis as a unifying framework for AD prevention and treatment.
Despite decades of research and billions of dollars invested, Alzheimer's disease treatment has been characterized by fragmentation, inconsistency, and limited success. The WIA-ALZHEIMERS standard addresses these challenges through unified approaches:
The WIA-ALZHEIMERS standard provides:
The WIA-ALZHEIMERS standard is built upon the ancient Korean philosophy of 弘益人間 (Hongik Ingan), meaning "to broadly benefit humanity." This philosophy guides every aspect of the standard:
With the aging of the global population, we face an unprecedented challenge. Without effective interventions, the number of people with Alzheimer's disease will triple by 2050, overwhelming healthcare systems worldwide. The WIA-ALZHEIMERS standard represents our commitment to meeting this challenge through unified, accessible, and evidence-based approaches.
In Chapter 2, we will examine the current treatment landscape for Alzheimer's disease, including approved medications, emerging therapies, and the limitations of existing approaches. This context will set the stage for understanding why NAD+ homeostasis represents such a significant paradigm shift in AD treatment.