17 May 2019

Many researchers and advocacy groups tout the benefits of a healthy lifestyle for preventing cognitive decline and dementia. Now the World Health Organization has weighed in, releasing a set of guidelines for lowering risk. The guidelines fall in line with recommendations from other groups, promoting exercise, a healthy diet, and treating chronic conditions such as hypertension and diabetes. Tedros Adhanom Ghebreyesus, director-general of WHO, introduced the guidelines at the May 15 World Dementia Forum meeting in Stockholm. They form part of the WHO’s global action plan to address dementia, issued in 2017.

“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,” the report notes.

Research on prevention has evolved since 2010, when the U.S. National Institutes of Health concluded the evidence was too weak to recommend any preventive measures (May 2010 news). In 2017 the National Academies of Science, Engineering, and Medicine (NASEM) noted modest evidence in favor of physical activity, cognitive training, and management of hypertension, but again stopped short of issuing recommendations (Jun 2017 news). However, a Lancet report that year judged that up to a third of dementia cases might be prevented by addressing modifiable risk factors such as midlife hearing loss, obesity, depression, and social isolation (Aug 2017 news). 

A group of experts convened by WHO conducted its own literature review and considered the relative benefit and harm of each proposed intervention to develop the guidelines. Their strongest recommendations were for physical activity, a balanced diet, and programs to stop tobacco use, because these have little risk of adverse effects and at least some evidence for delaying cognitive decline. The group also strongly recommended management of hypertension and diabetes, but also noted that in each case, the evidence for that intervention lowering dementia risk remains weak. Four other interventions—cognitive training, weight management, and treating alcohol abuse and high cholesterol—got the nod as well, but WHO noted a higher risk of harm from some of these interventions, and suggested that physicians make those decisions on a case-by-case basis. For social activity and treatment of depression and hearing loss, WHO concluded there was not enough evidence to make any recommendation at this time.

Across the field, health recommendations for dementia prevention are likely to be revised as more research rolls in. For example, the U.S. POINTER trial, part of the worldwide FINGERS study, tests the efficacy of a multidomain lifestyle intervention in a randomized clinical trial (Aug 2017 news).—Madolyn Bowman Rogers