Risk Reduction of Cognitive Decline and Dementia WHO Guidelines

 

Dementia is a rapidly growing global public health problem. Worldwide, around 50 million people have dementia, with approximately 60% living in low- and middle-income countries (LMIC). Every year, there are nearly 10 million new cases. The total number of people with dementia will reach 82 million in 2030 and 152 million in 2050. Dementia leads to increased costs for governments, communities, families and individuals, and to loss in productivity for economies. In 2015, the total global societal cost of dementia was estimated to be US$ 818 billion, equivalent to 1.1% of global gross domestic product (GDP).

Dementia Risks

Crucially, while age is the strongest known risk factor for cognitive decline, dementia is not a natural or inevitable consequence of aging. Several recent studies have shown a relationship between the development of cognitive impairment and dementia with lifestyle-related risk factors, such as physical inactivity, tobacco use, unhealthy diets and harmful use of alcohol. Certain medical conditions associated with an increased risk of developing dementia are hypertension, diabetes, hypercholesterolemia, obesity and depression. Other potentially modifiable risk factors include social isolation and cognitive inactivity. The existence of potentially modifiable risk factors means that prevention of dementia is possible through a public health approach, including the implementation of key interventions that delay or slow cognitive decline or dementia.

When making a strong recommendation, the Guideline Development Group (GDG) was confident that the desirable effects of the intervention outweigh any undesirable effects. When the GDG was uncertain about the balance between the desirable and undesirable effects, the GDG issued a conditional recommendation. Strong recommendations imply that most individuals would want the intervention and should receive it, while conditional recommendations imply that different choices may be appropriate for individual patients and they may require assistance at arriving at management decisions. The GDG members reached a unanimous agreement on all the recommendations and ratings.

The goals and objectives of the Risk Reduction of Cognitive Decline and Dementia WHO Guidelines

  1. To provide evidence-based recommendations on lifestyle behaviors and interventions to delay or prevent cognitive decline and dementia in the general population.
  2. To provide evidence-based recommendations on management of specific physical and mental health conditions to delay or prevent cognitive decline and dementia.

Summary of Recommendations

Physical Activity Recommendations:  

Physical activity should be recommended to adults with normal cognition to reduce the risk of cognitive decline.
Quality of evidence: moderate
Strength of the recommendation: strong

Physical activity may be recommended to adults with mild cognitive impairment to reduce the risk of cognitive decline.
Quality of evidence: low
Strength of the recommendation: conditional

Tobacco cessation interventions:

Interventions for tobacco cessation should be offered to adults who use tobacco since they may reduce the risk of cognitive decline and dementia in addition to other health benefits.                                                                     Quality of evidence: low
Strength of the recommendation: strong

Nutritional interventions:

The Mediterranean-like diet may be recommended to adults with normal cognition and mild cognitive impairment to reduce the risk of cognitive decline and/or dementia.                                                                                 Quality of evidence: moderate
Strength of the recommendation: conditional

A healthy, balanced diet should be recommended to all adults based on WHO recommendations on healthy diet.
Quality of evidence: low to high (for different dietary components)
Strength of the recommendation: conditional

Vitamins B and E, polyunsaturated fatty acids and multi-complex supplementation should not be recommended to reduce the risk of cognitive decline and/or dementia.                                                                     Quality of evidence: moderate
Strength of the recommendation: strong

Interventions for alcohol use disorders:

Interventions aimed at reducing ceasing hazardous and harmful drinking should be offered to adults with normal cognition and mild cognitive impairment to reduce the risk of cognitive decline and/or dementia in addition to other health benefits.

Quality of evidence: moderate (for observational evidence)                      Strength of the recommendation: conditional

Cognitive interventions:

Cognitive training may be offered to older adults with normal cognition and with mild cognitive impairment to reduce the risk of cognitive decline and/or dementia.
Quality of evidence: very low to low
Strength of the recommendation: conditional

Social activity:

There is insufficient evidence for social activity and reduction of risk of cognitive decline/dementia.

Social participation and social support are strongly connected to good health and well-being throughout life and social inclusion should be supported over the life-course.

Weight management:

Interventions for mid-life overweight and/or obesity may be offered to reduce the risk of cognitive decline and/or dementia.
Quality of evidence: low to moderate
Strength of the recommendation: conditional

Management of hypertension:

Management of hypertension should be offered to adults with hypertension according to existing WHO guidelines.
Quality of evidence: low to high (for different interventions)
Strength of the recommendation: strong

Management of hypertension may be offered to adults with hypertension to reduce the risk of cognitive decline and/or dementia.
Quality of evidence: very low (in relation to dementia outcomes)
Strength of the recommendation: conditional

Management of diabetes mellitus:

The management of diabetes in the form of medications and/or lifestyle interventions should be offered to adults with diabetes according to existing WHO guidelines.                                                                                    Quality of evidence: very low to moderate (for different interventions)
Strength of the recommendation: strong

The management of diabetes may be offered to adults with diabetes to reduce the risk of cognitive decline and/or dementia.
Quality of evidence: very low
Strength of the recommendation: conditional

Management of dyslipidaemia:

Management of dyslipidaemia at mid-life may be offered to reduce the risk of cognitive decline and dementia.
Quality of evidence: low
Strength of the recommendation: conditional

Management of depression:

There is currently insufficient evidence to recommend the use of antidepressant medicines for reducing the risk of cognitive decline and/or dementia.

The management of depression in the form of antidepressants and/or psychological interventions should be provided to adults with depression according to existing WHO mhGAP guidelines.

Management of hearing loss:

There is insufficient evidence to recommend use of hearing aids to reduce the risk of cognitive decline and/or dementia.

Screening followed by provision of hearing aids should be offered to older people for timely identification and management of hearing loss as recommended in the WHO ICOPE guidelines.

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Risk reduction of cognitive decline and dementia: WHO guidelines. Geneva: World Health Organization; 2019. Licence: CC BY-NC-SA 3.0 IGO.