How to prevent dementia?

Or, it's never too soon or too late to take care of the brain health!

Dementia is not an inevitable consequence of ageing and there are potential modifiable health and lifestyle factors that can prevent or delay its development. This represents a big advance.

Dementia has no cure and it is also is a global public health problem as a consequence of increased life expectancy. In 2015 about 50 million people were living with dementia worldwide and the expectation is that this number triple by 2050. Dementia causes disability and dependence in affected individuals as well as affects the family and carers who are at high risk of developing depression and anxiety disorders.

Those most affected by the rising incidence of dementia are the low- and middle-income countries while the higher-income countries are showing stable rates.

The symptoms probably represent the final stage of the disease in elderly, when the diagnosis usually occur, but the pathological modifications in the brain begin many years before, in the midlife (about 40-65 years), So, it is suggested that there is a window of opportunities in addressing dementia risk factors in middle age.

It is also known that not everyone will beneficiate by this considering genetic factor represents 65% of the risk of developing dementia.

There are nine combined potential risk factors attributable to 35% of the development of dementia, identified in a review published by The Lancet in July/2017:

Figure 1. Potential brain mechanisms for preventive strategies in dementia. From Livingston et al, 2017

• Low educational level: formal education for few years is related to less cognitive reserve and lack of resilience.

• Hearing loss: this is a relatively new factor associated with impairment in cognitive performance and environmental interaction.

• Hypertension: may accelerate the development of dementia by neuropathy of and by reducing cognitive reserve buffer.

• Obesity: related to inflammation and cardiovascular risk

• Smoking: related to atherosclerosis and cardiovascular risk

• Depression

• Physical inactivity: exercise has a neuroprotective effect by reducing vascular risk and reducing cortisol (stress hormone), although the evidence is not strong.

• Social isolation: related to cognitive inactivity and faster cognitive decline.

• Diabetes: associated with atherosclerosis and stroke, neurodegeneration and microvascular abnormalities glucose- mediated.

Other modifiable factors not included:

• Diet: There are still not enough studies to a criteria establishment, although it is considered an important modifiable factor.

• Cardiovascular risk: its prevention and reduction significantly changes the nine risks factors identified.

The FINGER Study (The Finnish Geriatric Intervention to Prevent Cognitive Impairment and Disability), in a two years follow-up, observed positive effects on cognitive performance in multimodal interventions (diet, exercise, cognitive training and vascular risk monitoring).

You may have noticed that the nine identified factors/interventions also confer other health benefits and are safe. And the implementation of targeted lifestyle strategies involves public health services, but also educational, laboral and agricultural sectors, for example.

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Livingston G, Sommerlad A, Orgeta V, Costafreda SG, Huntley J, Ames D, et al. Dementia prevention, intervention, and care. Lancet. 2017

Frankish H, Horton R. Comment: Prevention and management of dementia: a priority for public health. Lancet. 2017

Scarmeas N. Multimodal dementia prevention — does trial design mask efficacy? Nature Reviews Neurology. 2017

Prince M. Progress on dementia - leaving no one behind. Lancet. 2017.