9 lifestyle changes can cut dementia risk by one-third, say experts
One-third of dementia cases globally can be prevented by addressing nine lifestyle factors at different stages of life, beginning from better education during childhood, according to a report from The Lancet Commission on Dementia Prevention, Intervention, and Care.
“While it is undoubtedly never too early to attend to brain health, … it may also never be too late [to embark on lifestyle changes that may make a difference],” wrote Dr Martin Prince of King’s College London in London, UK, in a commentary. [Lancet 2017;doi:10.1016/S0140-6736(17)31757-9]
The 9 modifiable factors
Among the nine potentially modifiable risk factors identified, poor early life education was one of the top two factors associated with global dementia incidence. Less education, defined as a lack of secondary school education in the report, was associated with a 59 percent elevated risk of developing dementia (relative risk [RR], 1.59, 95 percent confidence interval [CI], 1.26–2.01). If people stayed in school up to age 15, as much as 8 percent of dementia cases could be prevented, according to the Commission. [Lancet 2017;doi:10.1016/S0140-6736(17)31363-6]
The top one risk factor in the list, hearing loss in midlife, accounted for 9 percent of the population risk for dementia. Hearing loss almost doubled the risk of dementia in a meta-analysis of three studies conducted by the Commission (pooled RR, 1.94, 95 percent CI, 1.38–2.73).
“Recognition of hearing loss as a risk factor for dementia is relatively new and … [t]he mechanism underlying cognitive decline associated with peripheral hearing loss is not yet clear,” said the experts, suggesting that hearing loss might lead to social detachment or depression. “The risk of hearing loss for dementia … [is] pertinent to many people because it is highly prevalent, occurring in 32 percent of individuals aged older than 55 years.”
Other potential risk factors in midlife included hypertension and obesity, which if eliminated, could reduce future dementia incidence by 3 percent, combined.
In late life, smoking ─ the third highest risk factor in the list ─ accounted for 5 percent of the potentially preventable fraction of dementia. By addressing the remaining modifiable risk factors in late life such as depression, physical inactivity, social isolation, and diabetes, dementia incidence could be reduced by another 10 percent.
“Although we have presented the available evidence about specific times when a risk factor has been shown to be important during the life course, it might be relevant at other times,” said the experts, recognizing that hypertension, diabetes, depression, being sedentary, smoking, and hearing loss may be relevant in both mid- and late life.
Collectively, by addressing the nine risk factors above, about 35 percent of dementia, or one in three cases might be prevented, according to the Commission.
As data on dietary factors, alcohol use, visual impairment, and sleep were unavailable, the authors were unable to include these other lifestyle factors into their evaluation, and hence, the overall contribution of lifestyle to dementia risk could be underestimated.
“While public health interventions will not prevent, or cure all potentially modifiable dementia, intervention for cardiovascular risk factors, mental health, and hearing may push back the onset of many people for years.” said lead author Professor Gill Livingston from University College London, UK. “Dementia prevalence could be halved if its onset were delayed by 5 years.”
The Commission comprised a panel of 24 international experts who systematically reviewed existing studies to provide evidence-based recommendations for preventing and managing dementia.
“Dementia is by no means an inevitable consequence of [ageing],” according to the Commission. “Many of dementia’s manifestations are now known to be manageable, and while the underlying illness is generally not curable, it might be modifiable with good dementia care.”
While treatment of cognitive symptoms ─ by offering cholinesterase inhibitors for Alzheimer’s disease or dementia with Lewy bodies, or memantine for severe dementia ─ is important; the experts also highlighted the potential benefits of nonpharmacologic interventions like exercise and social contact for managing neuropsychiatric symptoms of dementia, such as low mood, agitation, or psychosis.
“Dementia causes not only disability and dependency for individuals affected by the disorder, but can also have a profoundly detrimental effect on family and other carers, who are at high risk of developing depression and anxiety disorders,” wrote Drs Helen Frankish and Richard Horton, both editors of The Lancet from London, UK, in a commentary. [Lancet 2017;doi:10.1016/S0140-6736(17)31756-7] Recognizing this, the Commission called for support for family carers to be incorporated into the dementia care system.
In addition, the experts also suggested technological innovations could be useful in various aspects of dementia care, including diagnosis, monitoring, and carer support.
“Technological interventions have the potential to improve care delivery but should not replace social contact.”