No magic bullet to prevent dementia later in life
20th December 2017 -- There is no proven way to prevent dementia developing later in life, results of four reviews of the best available evidence have shown.
Investigators from the University of Minnesota in the US summarise findings from randomised controlled trials (RCTs) examining the effectiveness of physical activity, various prescription medications, over-the-counter vitamins and supplements, and cognitive training, in preventing the development of cognitive decline, mild cognitive impairment (MCI), and Alzheimer's-type dementia.
The reviews have been published online in the journal Annals of Internal Medicine.
"We looked at drugs. We looked at over-the-counter vitamins and supplements. We looked at exercise. We looked at cognitive training. And overall, the results didn't show much benefit," study investigator Dr Howard Fink, from the Geriatric Research Education and Clinical Center, Minneapolis, says in a podcast from the journal. However, one study that combined cognitive training, exercise, and diet did show "some improvement in cognitive outcomes," he says.
"When we looked at the evidence for group cognitive training, what we found was that people improved in the areas that they trained in, but that training did not extend to other areas. So, for example, if you trained in processing speed, there wasn't an improvement in memory," said co-investigator Dr Mary Butler, from the University of Minnesota.
Aim for a healthy, active life
For prevention of later life dementia, "there's no magic bullet," says Dr Butler but in those areas where there were potentially positive findings she says, "they are very consistent with public health types of messages that we hear all the time. Live a healthy life, eat a good diet, stay cognitively active and engaged socially."
With funding from the US Agency for Healthcare Research and Quality, the researchers took a critical look at the literature to determine whether any interventions had enough quality evidence to warrant a recommendation.
For physical activity, they reviewed data from 16 trials comparing a physical activity intervention with an inactive control. The evidence was "insufficient" for drawing conclusions about the effectiveness of aerobic training, resistance training, or tai chi for improving cognition. However, "low-strength" evidence showed that a multicomponent intervention that included physical activity, diet, and cognitive training improved several cognitive outcomes, they report.
The researchers reviewed data from 51 unique trials comparing the efficacy of various drugs with dummy-pills ( placebo), usual care, or active control on cognitive outcomes. The trials were rated as having a low to moderate risk of bias. The evidence did not support use of any of the studied drugs (dementia medications, antihypertensive agents, diabetes medications, nonsteroidal anti-inflammatory drugs or aspirin, hormones, and lipid-lowering agents) for cognitive protection in people with normal cognition or MCI, the authors report.
The review of cognitive training included 11 trials of adults with normal cognition or MCI at baseline. The trials had low to medium risk of bias. Cognitive training was mostly computer based for healthy adults and was done in group sessions for those with MCI.