Claudia Kimie Suemoto’s interest in the mechanisms associated with dementia arose during her care for the elderly. A geriatrician trained at USP, she felt limited because she was unable to offer patients effective treatments – there are no options capable of reversing Alzheimer’s disease, for example – and decided to try to better understand dementia, especially how to prevent it.
A step in this path is his recent study that points out the main risk factors for the Brazilian population, considering regional and racial differences. It also shows that prevention starts in childhood.
Published in the scientific journal Alzheimer’s & Dementia, the research indicates low education as the main risk factor for the general population. The other four main factors are: hypertension, hearing loss and obesity in middle age (between 45 and 65 years old), and lack of physical activity in old age.
“Education is a marker of cognitive reserve. This means that the more intellectually stimulated the individual is, the greater resistance he has in the face of injuries, for example, Alzheimer’s disease and vascular dementia”, says the researcher, who signs the work together with scientists from Brazilian and English institutions.
It’s like having a big savings and making small withdrawals. The amount decreases, but imperceptibly. Lesions occur, but there is no clinical manifestation because the cognitive reserve counterbalances it. For this to happen, however, it is necessary to “apply resources” from childhood.
“Our brain reserve takes place from the intrauterine period, going through early childhood and adolescence. The more you study, the more stimulating your job is, the greater the cognitive reserve”, says Suemoto.
The researcher comments that, like low education, other risk factors are associated with dementia, but are not its cause. That’s because dementia is like a big umbrella.
It is a syndrome, a set of signs and symptoms that has several biological causes. In the country, the three main ones are: Alzheimer’s disease; vascular dementia, which can occur after a stroke (stroke); and Lewy body dementia.
“If I examine these people’s brains, I will find Alzheimer’s disease as the cause, vascular dementia as the cause. Risk factors are lifestyle factors or previous illnesses that increase the risk, down the road, of having Alzheimer’s disease , vascular dementia or Lewy body dementia,” says Suemoto.
In work published in 2020, English professor Gill Livingstone, co-author of the new research, showed that 12 risk factors are associated with 40% of cases of dementia in the world (the rest correspond to unknown or not yet measured factors, such as diet) .
The idea with the survey in Brazil, carried out from the intersection of information from the IBGE and the Longitudinal Study of Health of the Elderly, was to verify how relevant these same aspects are in the country.
Overall, 48% of dementia cases here are attributable to 12 risk factors at different times in life: low education (under 45 years); hypertension, obesity, hearing loss, head trauma and alcohol consumption (between 45 and 65 years); smoking, depression, social isolation, lack of physical activity, diabetes and air pollution (over 65 years).
Rates, however, vary between regions with higher and lower GDP and between black and white individuals. In the North, Northeast and Midwest, risk factors are associated with 54% of cases and low education corresponds to 9.6%, followed by hypertension and hearing loss, each with 8.5%. In the South and Southeast, hypertension is the main aspect.
| Risk factors for dementia | Brazil | North, Northeast and Midwest |
South and Southeast | whites | black |
|---|---|---|---|---|---|
| Low education (less than 45 years old) | 7.7% | 9.6% | 7.7% | 6.8% | 8.2% |
| Hypertension (45 to 65 years old) | 7.6% | 8.5% | 7.8% | 7.3% | 7.7% |
| Hearing loss (45 to 65 years old) | 6.8% | 8.5% | 6.4% | 6.8% | 6.6% |
| Obesity (45 to 65 years old) | 5.6% | 5.7% | 5.9% | 5.7% | 5.3% |
| Lack of physical activity (over 65) | 4.5% | 5.1% | 4.5% | 4.4% | 4.4% |
| Depression (over 65 years old) | 4.4% | 3.8% | 5% | 5.0% | 3.8% |
| Head trauma (45 to 65 years old) | 3.1% | 3.5% | 3.1% | 3.1% | 3.0% |
| Diabetes (over 65 years) | 3.1% | 3.3% | 3.3% | 3.4% | 2.8% |
| Air pollution (over 65 years) | 2.7% | 2.7% | 2.9% | 2.8% | 2.5% |
| Smoking (over 65 years old) | 2.1% | 2.5% | 2.0% | 2.0% | 2.0% |
| Social isolation (over 65 years old) | 0.3% | 0.5% | 0.3% | 0.3% | 0.3% |
| Alcohol consumption (45 to 65 years old) | 0.3% | 0.3% | 0.3% | 0.3% | 0.3% |
In the case of hearing loss, there are still no established relationships. One of the hypotheses is that, as sound produces responses in the brain, the reduction or loss of the ability to hear would lead to a decrease in brain stimulation.
“It was a factor that caused us some surprise. We knew it was important, but not that much”, says the doctor.
Among whites and blacks, obesity appears as the fourth most important factor. Fifth, depression (whites) and lack of physical activity (blacks) appear.
Obesity in middle age is a factor associated with a higher risk of stroke and, in relation to physical activity, the author states that different studies indicate a relationship between exercises for the body and the stimulation of new brain connections.
“Our cut shows that the potential for prevention is greater in the North, Northeast and Midwest and that perhaps in these regions it is more important to improve education, while in the South and Southeast we value care with hypertension”, ponders Suemoto, one of the laureates in recent years with the award For Women in Science, promoted by L’Oreal, Unesco and the Brazilian Academy of Sciences.
I have over 8 years of experience in the news industry. I have worked for various news websites and have also written for a few news agencies. I mostly cover healthcare news, but I am also interested in other topics such as politics, business, and entertainment. In my free time, I enjoy writing fiction and spending time with my family and friends.
