GoKawiilSometimes, Kristine Yaffe will hear a poignant question from someone at her memory clinic. “I walk five miles a day, don’t drink and play bridge,” they’ll say, “so why do I have Alzheimer’s disease?”
How common is Alzheimer’s? Blood-test study holds surprises
Yaffe, a neurologist and dementia specialist at the University of California, San Francisco, finds it difficult to explain that even if someone does everything they can to lower the risk of dementia, there’s no guarantee they’ll avoid the condition.
Her struggles mirror a challenge in her field. Studies have identified a list of virtuous lifestyle choices associated with a reduced dementia risk, including a healthy diet, physical exercise and social and cognitive stimulation. Research has also pointed to some less obvious factors linked to lower risk, such as treating vision and hearing loss and, potentially, receiving a shingles vaccine. The trouble is that it’s hard to work out how much doing any — or all — of these things helps to reduce risk in the real world.
That’s not for lack of trying. A growing number of ambitious clinical trials have tested the effects of lifestyle interventions, providing people with intensive help to improve their diet, exercise regime, social connections and heart and brain health. These include the FINGER trial1, which involved some 2,650 participants testing a two-year lifestyle overhaul in Finland, and the multimillion-dollar POINTER study2, which tested a similar approach in the United States. These and other studies have suggested that lifestyle programmes can boost cognitive performance.
But these intensive interventions seem to help only slightly — a benefit equivalent to a modest boost on some memory tests. None has been shown to reduce the incidence of dementia, and critics argue that such programmes are costly and difficult to scale up.
Other trials, including offshoots of the FINGER study in the Netherlands and in 12 Latin American countries, will announce their results this month, and the World Health Organization will release its new dementia risk-reduction guidelines on 16 July. Deciphering the most effective ways to cut risks is important for researchers, clinicians and the public alike — especially given that the number of people with dementia worldwide is expected to soar in decades to come.
Blood test holds promise for predicting when Alzheimer’s symptoms will start
Some specialists worry that implementing lifestyle interventions won’t move the needle much; others argue that any reduction in the cognitive decline is worth the effort. Another concern is that researchers are over-emphasizing personal responsibility, when many important contributors to risk — such as air pollution and access to education and healthy food — are mostly outside people’s control. “This is a societal issue,” says Edo Richard, a neurologist at Radboud University Medical Center in Nijmegen, the Netherlands. “I think the focus has been too much on the individual lifestyle.”
Difficult calculations
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