By Joke Kujenya
POOR SLEEP, high blood pressure, hearing loss, social isolation and physical inactivity can increase the risk of cognitive decline over decades, while obstructive sleep apnea may further impair the brain’s ability to clear accumulated waste.
JKNewsMedia.com reports that international dementia research has increasingly focused on dementia as a condition shaped by lifestyle and physical changes over 20 to 30 years rather than solely by declining memory.
However, the International Academic Journal Lancet Healthy Longevity (IAJLHL) recently published a study analysing dementia-related data from 214,000 people aged 50 and above in 14 countries, including the United States (US), the United Kingdom (UK), South Korea, China and India.
The outcome emphasised that dementia does not begin at 80 but can begin at 50 and proposed shifting prevention strategies from a brain-centred approach to a lifestyle-centred one tailored to each country’s characteristics.
IAJLHL research also highlighted differences in risk factors between countries.
While obesity ranks highly among dementia risks in most developed countries, South Korea’s elderly obesity rate stands at 6.2%, compared with a 45% obesity rate in the US.
South Korea should therefore prioritise blood pressure control, the report said, noting that hypertension affects 37% of the population and is far more common than elderly obesity.
Elevated blood pressure can damage the brain’s small and delicate blood vessels, reducing the supply of oxygen and nutrients to tissues while damage to cerebral blood vessels can eventually destroy brain cells responsible for memory and judgement.
Heavy alcohol consumption also ranks relatively high among dementia risk factors in South Korea. Alcohol can raise blood pressure, disrupt sleep quality and increase falls and head injuries.
Hearing loss has also emerged as a major concern.
Also, the Lancet Dementia Commission (LDC) said it identifies hearing loss as the top risk factor, with poor hearing capable of reducing social interaction and brain activity, contributing to social isolation, depression and declining cognitive function.
The LDC report also stressed that hearing aids should be viewed as medical devices rather than symbols of old age.
South Korea’s health screening and chronic disease management system could also play a wider role in protecting brain health by detecting and managing hypertension, hyperlipidaemia and diabetes early, the LDC report notes.
It says that health screenings should include hearing and vision tests, depression screening, physical activity measurements and assessments of social isolation.
LDC also notes that the country has 256 Dementia Safety Centres (DSC) nationwide, which the report said should expand their role as prevention centres through community walking classes, volunteer programmes, book clubs, strength training, nutrition education, hearing consultations and sleep guidance.
The findings also stressed the importance of prevention beginning earlier in life.
Beta-amyloid, the causative agent of Alzheimer’s dementia, begins accumulating in the brain in people’s 50s, while hypertension can damage cerebral blood vessels at an early age.
It also suggests that dementia prevention should begin in people’s 40s and 50s as hypertension emerges, continue through middle age when diabetes and obesity increase, and extend into later adulthood as lower-body strength declines.
LDC counsels on daily brisk walking for at least 30 minutes, building lower-body strength, maintaining social contact, achieving deep sleep and using hearing aids early when needed all identified as measures that can help protect brain health.
Sleep Apnea And Brain Health
Meanwhile, poor sleep quality has also been linked to an increased risk of dementia through its effect on the brain’s ability to cleanse accumulated waste products.
A joint research team from the Department of Neurology at Bundang Seoul National University Hospital (DNBSNU), the Korea University College of Medicine Human Genome Research Institute (KUCMHGRI) and the Harvard Medical School Department of Sleep Medicine (HMSDSM) analysed sleep pathologies in obstructive sleep apnea patients.
The team tracked 1,110 adults participating in the Korean Genome and Epidemiology Study (KGES) for an average of 4.2 years.
They submitted that obstructive sleep apnea causes brief pauses in breathing during sleep, resulting in hypoxia and frequent awakenings that can make normal sleep difficult.
Researchers hypothesised that reduced function of the brain’s glymphatic system plays a key role in the link between sleep apnea and cognitive decline.
They also note that glymphatic system removes waste products that accumulate in the brain and is most active during deep sleep.
Their studies found that patients with sleep apnea showed significantly lower indicators of glymphatic system activity on MRI and markedly reduced visual memory scores.
The findings also suggested that sleep apnea affects cognitive decline indirectly through impaired glymphatic function rather than directly causing it, with the pattern becoming stronger as sleep apnea grew more severe.
Conversely, the researchers note patients whose condition improved through treatments such as positive airway pressure therapy and lifestyle changes showed recovery in both glymphatic activity and memory.
Professor Yoon Chang-ho said, “One must remember that sleeping well is the key to protecting brain health and preventing dementia.”
Conclusively, the findings reinforce the role of daily habits, cardiovascular health, social activity, hearing care and quality sleep in efforts to reduce dementia risks, with prevention beginning long before old age.
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