The number of people with dementia will increase significantly globally

(Visual China/Photo)

Dementia is a class of brain diseases that significantly affect the ability to perform daily life, the most common of which is Alzheimer's disease. Patients' cognitive abilities such as comprehension and memory will decline as a result, and even lose their ability to take care of themselves. This not only increases their own risk of survival, but also puts a lot of pressure on caregivers and other family members. As the population ages, the overall burden of the disease on social health systems and individual households is becoming more pronounced.

Recently, a new projection study published by the Global Burden of Disease Project estimates that by 2050, the number of people with dementia worldwide is likely to grow significantly from more than 57 million in 2019 to nearly 150 million, an increase of 166%. In the same time period, the number of people affected in China may increase from more than 15 million to more than 45 million, an increase of 197%, which is equivalent to a tripling increase.

Women are at higher risk

In addition to predicting the overall global situation in the next three decades, the study also made corresponding predictions by country and region. The number of people affected in China is expected to increase by nearly 200%, although it seems to be very high, but from the perspective of global growth, it is still at a moderate level, slightly higher than the global increase, not the extreme value. From a geographical point of view, the more extreme values are concentrated in North Africa, the Middle East, Europe and other places. For example, Qatar is expected to increase by 1926%, the United Arab Emirates by 1795%, Bulgaria by 37%, Greece by 45%, finland and Italy by more than 50%. The study was published in January 2022 in The Lancet Public Health.

Age remains an important indicator of dementia risk, and the older people are, the higher the risk of developing dementia. Globally, in terms of men aged 40 to 69, the proportion of men aged 40 to 69 is expected to have dementia is expected to be 0.5%, among those aged 70 to 84, this proportion is significantly increased to 6.5%, and for men over 85 years old, the risk of dementia can reach 23.5%. A similar pattern exists in women, except that the risk ratio is higher than that of men at all ages, and the total number is significantly higher than that of men.

This gender gap is not new, and for now, there have been many studies reporting that women have a higher rate of dementia than men. However, this gender difference does not yet have a definitive explanation, partly because women generally live longer than men, so there are more older women than men. However, there is evidence that there may also be differences in physiological mechanisms behind the gender differences between men and women, resulting in a difference in the risk of developing dementia.

In the case of a relatively stable sex-to-risk ratio, the key to the change in the number of people affected in different countries and regions lies in the number of people and the distribution of age. An increase in the total population, or an aging population structure, is more likely to lead to an increase in the number of people with dementia. Studies estimate that the increase in most dementia cases worldwide may be due to these two factors, and the role of the two can be said to be comparable. However, for different regions, the demographic changes they face are different.

For example, in sub-Saharan Africa, population growth is an important factor in driving up the number of local diseases, but for East Asia and Western Europe, population growth has slowed, but the age structure has aged, one by one, which has offset the increase in the number of people with dementia to some extent. A typical case is Japan, as a country with a deeper degree of aging, the study estimates that by 2050, the local dementia patients will increase by 27%, which is the lowest increase in the world.

There are many factors

On the basis of population size and structural changes, there are actually many factors related to the risk of dementia. The latest study is the first time that changes in risk factors for dementia have been taken into account, predicting the incidence of disease in nearly 200 countries and regions around the world. Special consideration is given to education, smoking, obesity, hyperglycemia, etc.

Education has a great effect on the development of people's cognitive abilities, and a large number of studies have found that the risk of dementia is lower if they receive more education. In 2019, a study in the Proceedings of the National Academy of Sciences (PNAS) also showed that with the increase in educational attainment, people reach a peak of cognitive ability around the age of 20, that is, in the late adolescence, and the education received thereafter, although still valuable for cognitive enhancement and maintenance, does not benefit as well as in childhood and adolescence.

The latest study found that in the next three decades, the average level of education can help reduce millions of people with dementia, but smoking, obesity, high blood sugar, etc. may also lead to millions of patients, so that the effect of education is almost offset, so the overall proportion of disease does not change much.

So, why do factors such as smoking and obesity have such an impact on the risk of dementia? Studies have found that smokers are generally at higher risk of developing dementia than non-smokers, but stopping smoking reduces this risk, even for older adults who have smoked for many years. Researchers at Seoul National University have found that researchers at Seoul National University have found that after four years of stopping smoking, the risk of dementia in elderly people who have smoked has been significantly reduced than those who have smoked continuously. But unfortunately, due to the large number of smokers in some places, a large number of people who do not actively smoke are actually exposed to second-hand smoke and passively smoke a lot of smoke. Observational studies have found that middle-aged and elderly women who do not smoke may also have higher memory decline because of second-hand smoke.

The relationship between obesity and dementia has also been supported by more and more evidence, and more critically, obesity as a new global health risk has not received enough attention compared to the effects of global tobacco control actions, and obese people are still increasing. In addition to obesity, excessive alcohol consumption is also a more common risk factor, and people who drink excessively have a higher risk of cognitive impairment and dementia, and the social and cultural factors behind this behavior make the risk of dementia associated with drinking more complicated.

In addition to these risk factors, the factors that scientists have identified that may be related to dementia include high blood pressure, brain injuries, hearing impairment, diabetes, air pollution, depression, social isolation, exercise, and more. For people of different ages, identifying these factors that may lead to dementia and thus a targeted risk aversion is particularly important at the current level of science.

The focus is on prevention

Dementia is still irreversible, and the key to this kind of cognitive impairment lies in prevention. Although the specific mechanism of the disease is still not very clear, for some of the risk factors that have been identified, taking measures in advance to intervene in cognitive ability can reduce the risk of dementia. And although the disease is generally considered to be a geriatric disease, people of different ages can take appropriate measures to protect their cognitive abilities.

For young people, the key is to receive education, especially before adulthood, and to grasp the critical stages of cognitive development. Even in adulthood, even in the middle-aged and elderly stages, it is still possible to improve and maintain existing cognitive abilities by continuing to participate in education or various cognitive activities. The human brain is generally used in and out, as long as it can activate the brain, whether it is reading or playing, it may improve cognitive ability. In this regard, people who need more mental work may have a natural advantage in maintaining richer cognitive activity until retirement.

After retirement, it is still necessary to maintain some physical activity and social activities. After middle age, the older the age, the smaller the circle of friends, which is especially serious for unmarried or widowed elderly people. In such a situation, how to broaden and maintain your social connection with others and avoid social isolation is very helpful for maintaining and protecting cognitive ability. Combined with the available scientific evidence, participation in music, dance, physical exercise, etc. may be beneficial.

In addition to the individual's attention to their own situation, the latest research through the next thirty years of dementia number of people, in fact provide a reference for public health policy, considering the large base of Chinese, in the face of the exponential growth of related patients and the reduction of young people, how to provide better care for the disabled elderly is a social problem to be solved.

Southern Weekend reporter Wang Jiangtao