World Alzheimer's Day: One in 10 Koreans aged 65 and older has dementia

Every year, September 21 is World Alzheimer's Day, designated by the World Health Organization (WHO) and Alzheimer's Disease International (ADI).

With increasing life expectancy and a growing global population of older adults, dementia is becoming a serious social issue. Dementia is a degenerative brain disease that mainly affects people aged 65 and older.

In 2023, one in 10 older adults in Korea had dementia. According to the Central Dementia Center of the Ministry of Health and Welfare, as of March this year, the number of people aged 65 and older exceeded 10 million, of which 1,052,977 had dementia.

According to statistics from the Health Insurance Review and Assessment Service (HIRA), the number of patients who received dementia treatment in Korea increased from 551,845 in 2019 to 674,963 in 2023, up a whopping 22.3 percent in four years. Despite this increasingly serious problem, there is still no cure for dementia, and the disease is often quite advanced by the time dementia symptoms appear.

Therefore, early diagnosis and appropriate treatment are critical to slowing the progression of the disease.

Dementia is a condition in which the brain's cognitive function declines in an otherwise normal person, making it difficult for them to make decisions or perform tasks. It is an acquired decline in various intellectual abilities, including memory, language, spatial and temporal organization, judgment, and abstract thinking. Alzheimer's disease (AD), the most common degenerative brain disease that causes dementia, affects more than 70 percent of people with dementia.

The exact pathogenesis and cause of Alzheimer's disease is not yet clarified, but it is believed to be caused by the formation of neurofibrillary knots in the nerves made up of abnormal amyloid-beta protein and hyper-phosphorylated tau protein that accumulate in the brain. Alzheimer's disease is characterized by a very slow onset and gradual progression.

In the early stages of the disease, memory declines. In the middle stages, it is accompanied by many cognitive abnormalities, including language and judgment. Psycho-behavioral symptoms, including personality changes, agitated behavior, depression, delusions, hallucinations, increased aggression, and sleep disturbances, are common as the disease progresses. In the late stages, neurological impairments, such as gait abnormalities and physical complications, including infections and pressure sores, can occur.

The challenge with Alzheimer's disease is that it worsens progressively, and its mild initial symptoms make it difficult to detect early. By the time they become visible, dementia is often quite advanced. Once diagnosed with Alzheimer's disease, there is no way to halt or reverse the progression of brain damage, so the focus should be on early diagnosis and active management to slow the progression of dementia before it gets worse.

Alzheimer's disease-modifying therapies (DMTs) that help delay the progression of the disease must be diagnosed early in the disease to maximize their effectiveness.

If Alzheimer's disease is suspected, cognitive and behavioral performance is evaluated through a questionnaire between the caregiver and the patient, and brain imaging diagnostics such as MRI and PET CT (positron emission tomography) are performed to check for cerebrovascular disease and brain atrophy.

However, the existing diagnostic method, PET CT, is a test that measures the amount of radiation generated after injecting a drug (FDG-F18) composed of a radioactive isotope into the body. Still, there is a risk of carcinogenesis if there is repeated exposure to a large amount of radiation. The cost and diagnosis time are burdensome. It also has limitations for those with claustrophobia, requiring the test to be performed in an enclosed space.

Recently, the “two Alzheimer's disease marker test (Cerebrospinal Fluid or CSF test)” has been gaining attention because it can detect amyloid-beta and tau protein, biomarkers of Alzheimer's disease, in a single test without radiation exposure. The diagnosis time and cost are reasonable. This test shows that changes in the concentration of amyloid-beta and tau proteins in the cerebrospinal fluid correspond to their accumulation in brain tissue changes in the cerebrospinal fluid, and early diagnosis of Alzheimer's disease is made by observing these characteristic changes in concentration.

In addition, in a study of 277 patients with mild cognitive symptoms who were amenable to undergo both the amyloid PET CT scan and the Alzheimer's disease marker test, the two Alzheimer's disease marker tests showed a high positive concordance rate (90.9 percent) and negative concordance rate (89.2 percent) with conventional amyloid PET CT scan results. This proves the two Alzheimer's disease marker tests can replace the PET CT test.

“Dementia is a disease that causes mental and economic distress not only to the patient but also to the family, so early diagnosis and active treatment should be prioritized,” said Dr. Ahn Sun-hyun, a specialist in the Department of Diagnostic Tests at the GC Labs, a medical foundation. “If you have a loved one who is suspected of having Alzheimer's disease, we recommend that you take the two Alzheimer's disease marker tests (CSF tests), which can be tested without radiation exposure.”