According to a recently published study, younger generations in modern society are less likely to develop dementia at the same age compared to previous generations. This trend is particularly pronounced in women, suggesting that positive effects of improved medical and educational environments for healthy living are being confirmed. However, a cautionary note is also raised: considering the global aging trend, the overall burden of dementia is expected to continue to increase.

 
Decreased Dementia Incidence Across Generations… Hopeful Research Findings

Dr. Sabrina Lenzen from the Centre for Health Business and Economics at the University of Queensland, Australia, emphasized, "Younger generations are at a lower risk of developing dementia at the same age as their parents or grandparents, which is a hopeful sign." Dr. Lenzen attributed these positive changes to several factors: improved cardiovascular health management, higher educational attainment, improved quality of living environments, and better access to healthcare services.

The study, published in the JAMA Network Open, analyzed extensive data from 62,437 individuals aged 70 and older born between 1890 and 1948 in the United States, Europe, and the United Kingdom. The research team meticulously analyzed participants by segmenting them into eight birth cohorts (similar groups) and six age groups. Birth cohorts were roughly grouped into 5-year intervals, with the early cohort comprising individuals born between 1890 and 1931, and the most recent cohort consisting of those born between 1944 and 1948. Age groups were divided into 5-year intervals from 71-75 years old to 96 years old and above, to closely examine changes in dementia prevalence according to generation and age.

The analysis revealed a statistically significant decrease in the number of people with dementia in more recent birth cohorts compared to earlier cohorts. This trend was consistent across different regions. For instance, in the United States, 25.1% of 81-85-year-olds born between 1890 and 1913 suffered from dementia, but this figure dropped significantly to 15.5% for the same age group born between 1939 and 1943. In Europe, the dementia prevalence for 81-85-year-olds born between 1934 and 1938 was 30.2%, but it nearly halved to 15.2% for those born between 1939 and 1943. The UK also showed a decreasing trend, with dementia prevalence for 81-85-year-olds born between 1924 and 1928 at 15.9%, compared to 14.9% for the same age group born between 1934 and 1938.

 
Key Factors in Dementia Incidence Reduction: Education and Cardiovascular Health

Co-author Dr. Lenzen identified improved education levels as a core reason for the decrease in dementia incidence. She particularly emphasized that "women's education levels have significantly improved," suggesting this likely had a greater impact on the reduction of dementia incidence in women. Education is known to enhance cognitive reserve, which is the brain's ability to maintain cognitive function despite aging or pathology. The general academic view is that higher education levels create a more complex and flexible brain network, increasing its resilience to brain damage.

Furthermore, improvements in cardiovascular health were also cited as an important factor. Dr. Lenzen explained, "Blood pressure and cholesterol levels were better managed, both of which are risk factors for dementia." Hypertension, high cholesterol, and diabetes are known major risk factors for not only vascular dementia but also Alzheimer's disease. In Western societies, since the 1970s, awareness of cardiovascular disease prevention and treatment has increased, and medical technology has advanced, leading to a decrease in the prevalence of hypertension and high cholesterol, and more effective management. This is believed to have contributed to lowering the risk of dementia by improving blood flow to the brain and reducing the risk of cerebrovascular diseases like stroke.

 
Why More Women Have Dementia and the Impact of Education

According to the World Health Organization (WHO), as of 2021, there are 57 million people with dementia worldwide, and 65% of dementia-related deaths are women. This indicates that women are more susceptible to dementia. Various theories exist regarding the higher prevalence of dementia in women, with key factors including: women's longer average lifespan (dementia incidence increases with age), estrogen reduction due to menopause (weakening of brain protective effects), and lack of educational opportunities (lower education levels of women in past generations).

The fact that the reduction in dementia incidence was more pronounced in women in this study strongly suggests that the significant improvement in education levels among women in recent generations, compared to periods when women's educational opportunities were limited, has had a positive impact on dementia prevention. This can be seen as crucial evidence supporting the hypothesis that education enhances cognitive reserve, thereby delaying the onset of dementia or reducing its incidence.

 
Longer Lifespan and the Paradox of Dementia: Total Patient Count Increases

Dr. Lenzen clearly stated that this research result does not refute the statistics showing an increase in recent dementia prevalence. She explained, "As lifespans lengthen, the total number of people diagnosed with dementia is bound to increase." This illustrates the "paradox of dementia," where even if the dementia incidence rate decreases for individuals within each age group, the absolute number of people suffering from dementia will inevitably increase due to the overall aging of the population.

Indeed, the WHO predicts that the global dementia population, which was 57 million in 2021, will sharply increase to 78 million in 2030 and 139 million in 2050. South Korea, too, is expected to see a rapid increase in dementia patients as it approaches a super-aged society. According to the National Dementia Center under the Ministry of Health and Welfare, the number of dementia patients aged 65 and over in Korea is estimated to be around 980,000 in 2023, and is projected to reach 1.36 million in 2030 and 3.02 million in 2050. These statistics imply that regardless of how much the risk of dementia onset decreases for each generation, the immense social and economic burden brought by demographic changes cannot be overlooked.

 
Importance of Continued Government Investment and Preparedness for New Risk Factors

While the study's findings offer some hope, Dr. Lenzen pointed out that continuous government investment in dementia prevention is necessary, as the overall burden of dementia due to population aging will continue to increase. She expressed concern, stating, "Some risk factors are improving, but changes are appearing in other dementia risk factors, such as high obesity rates and air pollution. It is not certain whether the trend [of decreasing dementia prevalence in younger generations] will continue."

Indeed, modern society faces new dementia risk factors that did not exist in past generations. Increased obesity and metabolic syndrome: Due to Westernized diets and sedentary lifestyles, the prevalence of metabolic diseases such as obesity, diabetes, and hyperlipidemia is rapidly increasing. These can act as major risk factors for dementia. Air pollution: Recent studies warn that air pollutants such as fine dust can cause brain inflammation and increase the risk of cognitive decline and dementia. With intensifying urbanization, air pollution has become a global issue. Sleep deprivation and poor sleep quality: Irregular sleep habits and chronic sleep deprivation in modern people can negatively affect brain health and increase the risk of dementia. This is because the brain's waste removal system operates during sleep, and sleep deprivation disrupts this process. Social isolation and loneliness: With aging and the trend towards nuclear families, the number of elderly people experiencing social isolation is increasing, which acts as a factor raising the risk of depression, cognitive decline, and ultimately dementia.

These new risk factors also have the potential to offset or reverse the trend of decreasing dementia incidence across generations. Therefore, governments and societies must maintain and strengthen the successful factors of the past while proactively preparing for new risk factors. For example, policies to reduce air pollution, national health campaigns for obesity prevention, creation of environments for quality sleep, and development of programs to encourage social participation among the elderly are all necessary.

 
Conclusion: Balancing Optimism and Vigilance

This study delivers a hopeful message that the development of medical and educational systems can delay the onset of dementia and reduce its prevalence. It particularly re-emphasizes the importance of women's education. However, it is crucial not to overlook the fact that the overall burden of dementia will still increase within the grand trend of aging, and new risk factors like obesity and air pollution are emerging.

Ultimately, the fight against dementia is a long-term challenge that requires not only individual efforts but also continuous government investment and the attention of society as a whole. Now is the time for a wise approach that further strengthens the positive factors revealed by the research and prepares for new challenges that may be faced in the future. We must hold onto hope but not let down our guard, and continue our efforts for a healthy future free from dementia.

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