Dementia gives up on education

Natalia Reznik, "Trinity Variant"

The world's population is aging, and with age come diseases, including senile dementia, or senile dementia. This is called the weakening of memory and cognitive functions, which developed as a result of the death of neurons in the brain. Violations are so severe that people cannot live independently. According to the World Health Association, more than 46 million people suffer from senile dementia, and experts expect that by 2050 the number of patients will almost triple. However, in some developed countries, senile dementia has begun to recede over the past quarter century, contrary to forecasts.

So, in England from 1991 to 2011, the number of diseases was 24% less than expected, which is about 200 thousand cases. Among the elderly participants of the Framingham Heart Study program, which has been conducted by Boston University since 1948 to determine the risk factors for cardiovascular diseases, the incidence of dementia decreases by about 20% every 10 years from 1977 to 2008, but only in people with completed secondary education. And this is despite the fact that in developed countries the number of obese patients is rapidly growing, which entails hypertension, diabetes with vascular complications and elevated cholesterol levels, and these are all risk factors for senile dementia, which is provoked, in particular, by atherosclerosis and high blood pressure. In the United States, the proportion of obese people 65 years and older increased from 23% in 1990 to 35% in 2012, and the prevalence of diabetes increased from 9% to 21%.

Experts see two main reasons for this phenomenon. Firstly, cardiovascular diseases have become better treated. In particular, doctors have learned how to effectively prevent strokes and heart attacks in diabetic patients, therefore, the risk of developing dementia due to insufficient blood supply or death of brain areas is also reduced. Secondly, the prevalence of dementia was influenced by the growing level of education. And it's not just that prolonged stimulation of brain activity allows you to create a cognitive reserve, that is, the ability of the brain to cope with the consequences of its damage. A higher level of education is more often associated with a healthy lifestyle, that is, physical activity, proper nutrition, smoking cessation, more intellectual pursuits and access to good medical care. Each of these factors reduces the likelihood of developing dementia.

All these considerations have been expressed repeatedly and confirmed by many studies. Specialists from the University of Michigan also contributed to understanding the causes of age-related dementia. They acted as part of their large-scale Health and Retirement Study (HRS), launched in 1992 and collecting data on the health, mental abilities, marital status, occupations and material well-being of residents of the United States 65 years and older. HRS monitors the fate of participants before their death, and new people are regularly included in the study. Scientists were interested in how the incidence of senile dementia in the United States changed between 2000 and 2012. In 2000, they interviewed 10,546 respondents, 12 years later – 10,516. If an elderly person could not pass the test, the researchers tried to find a close relative who could answer the questions. If possible, such a third–party informant was found even in the case when the participant could answer the test questions himself, for greater objectivity.

The results of the study confirmed a well-known trend. In 12 years, the prevalence of senile dementia in the United States has decreased from 11.6% to 8.9%. The share of less pronounced age-related cognitive impairments also decreased: from 21.2% to 18.8%. The average age of the study participants has not changed, it is approximately 75 years old, but in the 2012 cohort the proportion of people over 85 years old is higher.

The decline in dementia is indeed accompanied by an increase in the education of Americans. In 2000, 32.6% of respondents did not have completed secondary education, and only 16.6% had completed more than 16 years of higher education; in 2012, there were 20.6% and 23.6% of such people, respectively. The average number of years spent by a person on training has increased by about a year. The researchers limited themselves to this formal indicator, without specifying what exactly the survey participants studied and how well.

The prevalence of cardiovascular diseases has increased in 12 years from 29.1% to 31.6%, while the frequency of strokes has remained the same. Indeed, medicine has learned to maintain the vessels in a relatively decent condition.

There are much more elderly people with obesity and diabetes. Obesity, it turns out, reduces the risk of dementia, but only if it develops in old age. Having arisen in the middle of life, it can increase the risk of cognitive impairment in the future.

Diabetes is fraught with vascular disorders and increases the risk of developing dementia by 39%. The prevalence of diabetes among the survey participants increased from 16.4% to 24.7%, but they are not as ill as before, because they are better treated. The proportion of diabetic patients taking medications has increased from 86% to 90%; as a rule, they do not reach strokes, heart failure and amputations.

Socio-economic factors related to education level, income level and race, although they influence the likelihood of developing dementia, do not explain the differences between the two cohorts.

Of course, progress in the treatment of cardiovascular diseases and diabetes has played an important role in the fight against dementia. However, the full set of social, behavioral and medical factors influencing the spread of dementia has not yet been established. In particular, the researchers themselves did not take into account the genetic predisposition to successful learning and the risk of cognitive impairment.

Nevertheless, the researchers believe that the cognitive reserve resulting from long-term, early learning will reduce the risk of dementia. And this recipe is suitable for any country in the world.

Source: Langa et al., A Comparison of the Prevalence of Dementia in the United States in 2000 and 2012 (JAMA Internal Medicine, 2017).

Portal "Eternal youth" http://vechnayamolodost.ru  20.03.2017