Batya Swift Yasgur, MA, LSW
May 15, 2019
The new guidelines are designed to "provide the knowledge base for healthcare providers governments, policy-makers, and other stakeholders to reduce the risk of cognitive decline and dementia through a public health approach," writes Dr Ren Minghui, Assistant Director-General, Universal Health Coverage/Communicable and Noncommunicable Diseases, WHO, in a foreword to the guidelines.
The rise in dementia and Alzheimer's disease is alarming and is expected to double every 20 years, from 47 million people in 2015 to 75 million in 2030 and 131 million in 2050.
This means that in the next 30 years, "the number of people with dementia is expected to triple [and] we need to do everything we can to reduce our risk of dementia," WHO Director-General Tedros Adhanom Ghebreyesus, MSc, PhD, said in a press release.
The guidelines are a component of the WHO's Global action plan on the public health response to dementia 2017-2025, a broad-based approach to dementia reduction launched in 2017 that also includes strengthening information systems for dementia, improved diagnosis, treatment, and care; supporting caregivers of individuals with dementia; and research and innovation.
"The scientific evidence gathered for these Guidelines confirms what we have suspected for some time, that is what is good for our heart is also good for our brain," Ghebreyesus said.
Physical activity should be recommended to adults with normal cognition to reduce the risk for cognitive decline.
The authors state that the "physical activity interventions evaluated in the included trials were resource-intensive, since such interventions are usually supervised and are conducted in a facility. However, some aspects of these interventions, could be adapted to particular settings, and could be conducted by suitably trained and supported non-specialists."
There are "potentially lower costs for aerobic training, compared to resistance [training]," they note.
Interventions for tobacco cessation should be offered to adults who use tobacco, as they may reduce the risk for cognitive decline and dementia in addition to providing other health benefits.
One obstacle to implementing these interventions is that they are "resource-intensive as they may require professional guidance and supervision," the authors write.
Group-based guidance and e-interventions may reduce costs.
The Mediterranean diet may be recommended to adults with normal cognition and mild cognitive impairment (MCI) to reduce the risk for cognitive decline and/or dementia.
A healthy, balanced diet should be recommended to all adults based on WHO recommendations on healthy diet.
Vitamins B and E, polyunsaturated fatty acids, and complex multivitamin supplementation should not be recommended to reduce the risk for cognitive decline and/or dementia (quality of evidence: moderate; strength of the recommendation: strong).
The researchers reviewed nine different interventions/comparisons:
- Supplement multicomplexes vs placebo in adults with normal cognition
- Supplement multicomplexes vs placebo in adults with MCI
- Polyunsaturated fatty acids vs placebo
- Vitamin B vs placebo
- Vitamin E vs placebo
- Six polyphenols vs placebo
- Protein supplementation vs placebo
- Chicken essence vs placebo
- Mediterranean diet vs alternate or usual diet
Polyphenols was the only category of supplement and nutraceuticals shown consistently to affect cognition beneficially, although the evidence was deemed to be "of low quality."
The authors concluded that, on the whole, dietary modification is "safe" and adverse events are "rare," although vitamin E and protein supplementation at high doses may have "undesirable non-anticipated effects."
Interventions aimed at reducing or ceasing hazardous and harmful drinking should be offered to adults with normal cognition or MCI to reduce the risk for cognitive decline and/or dementia, in addition to other health benefits.
Although the researchers were unable to identify specific systematic reviews or single studies investigating the effect of alcohol reduction intervention on the risk for dementia and/or cognitive decline, a "large body of observational evidence" correlates heavy alcohol drinking with increased risk for cognitive impairment and dementia. Group-based guidance and e-interventions may be helpful in reducing the cost of intervention.
Cognitive training may be offered to older adults with normal cognition or with mild cognitive impairment to reduce the risk for cognitive decline and/or dementia.
There was no evidence for the impact of cognitive stimulation vs usual care or no intervention on cognitive function in older adults with MCI or incident dementia. However, "low-quality evidence" suggested that cognitive training might reduce incident dementia and improve cognitive functions and activities of daily living in adults with MCI.
There is insufficient evidence for social activity and reduction of risk for cognitive decline/dementia.
Social participation and social support are strongly connected with good health and well-being throughout life, and social inclusion should be supported over the life course.
The authors note that the research evidence "probably favors the intervention" but "further research is required to determine the type, form, and duration of social activity intervention which would be efficacious for the target outcomes."
Interventions for midlife overweight and/or obesity may be offered to reduce the risk for cognitive decline and/or dementia (quality of evidence: low to moderate; strength of the recommendation: conditional).
The authors note that moderate-quality evidence "suggest that weight-loss through lifestyle interventions improve cognitive performance at least in some domains," with the main barriers to implementation being cost, lack of motivation, lack of time, and physical limitations.
The authors recommend that individuals follow the WHO guidance on overweight and obesity.
Management of hypertension may be offered to adults with hypertension to reduce the risk for cognitive decline and/or dementia (quality of evidence: very low [in relation to dementia outcomes]; strength of the recommendation: conditional).
Cost of antihypertensive medication depends on the drug administered, but they can be "cost-effective," the authors add.
Blood Glucose, Cholesterol
The authors recommend the WHO Package of Essential Noncommunicable (PEN) Disease Interventions for Primary Health Care in Low-Resource Settings (2010) as a relevant guideline.
The authors note that antidiabetic medication and physical activity are already being recommended as treatment options for patients with diabetes, noting the important role of diet and physical activity along with lowering blood glucose.
Management of dyslipidemia at midlife may be offered to reduce the risk for cognitive decline and dementia (quality of evidence: low; strength of the recommendation: conditional).
The authors encourage a "life-course perspective…since…detecting dyslipidemia earlier in life could have beneficial effects and that is why the timing of the intervention is particularly important."
They note that their evidence suggests that controlling dyslipidemia through statin treatment in older adults (age = 65 years) "does not seem to have an effect on the incidence of dementia (low-quality evidence) and/or cognitive decline (moderate-quality evidence)."
There is currently insufficient evidence to recommend the use of antidepressant medicines for reducing the risk for cognitive decline and/or dementia.
The authors note that some evidence favors the use of the antidepressant vortioxetine for reducing the risk for cognitive decline/dementia.
There is insufficient evidence to recommend use of hearing aids to reduce the risk for 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.
Some research has suggested that use of hearing aids may be associated with improvements in cognitive function, but the benefits have been limited.
There is also no data available with respect to the cost of hearing aid interventions in the studies included. The resource requirements of hearing aid interventions are likely to involve associated costs for hearing assessments, audiology appointments, and hearing aid devices, which will vary among healthcare policies and different countries.
Any national approach to dementia must include support for caregivers of people with dementia, according to Devora Kestel, MSc, director of the Department of Mental Health and Substance Abuse at the WHO.
"Dementia carers are very often family members who need to make considerable adjustments to their family and professional lives to care for their loved ones," she said in a press release.
"This is why WHO created iSupport, an online training program providing carers of people with dementia with advice on overall management of care, dealing with behavior changes, and how to look after their own health," she added.