There are various risk factors that can predispose people to developing dementia. Some of these can be changed, while others cannot. Among those that cannot be changed are age and sex. However, there are other triggering factors that depend mainly on a person's lifestyle and thus, can be changed; reducing the risk of onset of dementia in the future.
1. Low educational level
Cognitive stimulation through education, especially in the early stages of life, leads to a 5% lower risk of dementia. Promoting lifelong learning and engaging in cognitive, physical and social activities during adult life are crucial for protecting brain health.
This is the only risk factor that can be reduced in childhood and adolescence. The remaining factors all have an impact in adulthood while others, such as social isolation, affect older people more.
2. High LDL cholesterol
A high level of LDL cholesterol, known as “bad” cholesterol, especially in middle age, contributes to 7% of cases of dementia. This excess is associated with stroke and an accumulation of beta-amyloid and tau proteins, related to Alzheimer's disease. Statins, cholesterol-lowering drugs, can help reduce this risk.
3. Hearing loss
20% of the world's population suffer from hearing loss. For every 10dB decrease in hearing ability, the risk of dementia increases. Treating hearing loss, by using hearing aids, for example, can reduce this risk.
4. Depression
The relationship between depression and dementia is bidirectional: it can be both a cause and a consequence of cognitive decline. It increases the chances of developing dementia by 3%. It is thought that depression may play a role by reducing self-care and social contact, or through biological mechanisms, such as inflammation and stress in the brain.
5. Head trauma
Blows to the head, regardless of their cause, increase the risk of dementia by 3%. Contact sports, such as football, where frequent heading occurs, are associated with an increased risk. It is recommended to use protection and to limit repeated impacts.
6. Smoking
Long-term smoking is also associated with 2% of cases of dementia. Stopping smoking can significantly reduce this risk.
7. Physical inactivity
A lack of exercise is linked to a 2% increased risk of dementia. Physical activity improves blood flow and reduces inflammation, which protects the brain.
8. Diabetes
The onset of diabetes also increases the risk of dementia by 2%, especially if it is poorly managed. The mechanisms involved include vascular problems and insulin resistance, which increases the toxicity of beta-amyloid proteins in the brain.
9. High blood pressure
High blood pressure after the age of 40 increases the risk of dementia by 2%. Maintaining blood pressure below 130 mmHg may be beneficial.
10. Obesity
Excess weight is closely related to other risk factors, such as inactivity, diabetes and hypertension. Even moderate weight loss can improve cognition in the short term, according to some studies.
11. Excessive alcohol consumption
Drinking more than 21 units of alcohol per week increases the risk of dementia by 1%. In addition, alcohol-induced blackouts increase this risk, even among moderate drinkers.
12. Untreated visual problems
12.6% of the world's population has visual difficulties, and this contributes to 2% of dementia cases. Among the causes of visual disturbances, cataracts and diabetic retinopathy are linked to an increased risk.
13. Air pollution
Particulate matter (PM2.5/PM10) affects cognition. In low-income countries, the use of solid fuels for cooking also increases the risk of cognitive decline and dementia by 3%.
14. Social isolation
Limited social contact is associated with a 5% higher risk of dementia. Social interaction promotes cognitive reserve, encourages healthy habits and reduces stress and inflammation.
Socioeconomic context
It is also important to note that socioeconomic conditions profoundly influence the likelihood of developing this disease, as they affect diet, medical care and exposure to pollutants.
Other variables, such as sleep disorders, poor nutrition and mental illness (including anxiety and schizophrenia) have also been evaluated; however, no strong evidence to include them as direct risk factors has yet been found, although they are still under study.
These data highlight the importance of promoting healthy lifestyles to prevent all types of diseases, both physical and psychological. Good exercise, eating and social life habits increase life expectancy and, most importantly, substantially improve quality of life.
Information documented by:
Dr Albert Lladó and Guadalupe Fernández, Neurology Department, Hospital Clínic Barcelona.
