PLANNING cities that better accommodate socialising, exercise and access to healthy eating will be key to preserving the cognitive health of younger generations, according to a leading health expert.
Professor Joseph Ibrahim, consulting physician in geriatric medicine and fellow of the Australasian Faculty of Public Health Medicine, told MJA InSight that doctors needed to advocate at a public policy level to encourage a greater commitment to long-term health initiatives.
“We may not see the benefit of this for 10‒30 years, but we need to push for it now, and not just wait until people get older and get sick.”
Professor Ibrahim was responding to two US studies published last week in JAMA
. The first study found that among sedentary older adults, a 24-month moderate-intensity physical activity program compared with a health education program did not result in improvements in cognitive function. (1)
The research included 1635 people aged 70‒89 years at risk for mobility disability but able to walk 400 m, who were randomised to receive either a physical activity intervention or education program.
The authors found that there was no significant difference between groups in the incidence of mild cognitive impairment or dementia.
A second randomised trial found that among people with age-related macular degeneration (AMD), oral supplementation with long-chain polyunsaturated fatty acids (LCPUFAs) or lutein/zeaxanthin had no statistically significant effect on cognitive function. (2)
The research included 3501 people who underwent cognitive function testing. The participants, who had a mean age of 72.7 years, were at risk for developing AMD were assigned to 1 g of LCPUFAs and/or the dietary supplements lutein (10 mg)/zeaxanthin (2 mg), or placebo over 5 years. As well as annual eye examinations, several validated cognitive function tests were administered every 2 years during the study period.
An accompanying editorial said these results “should not lead to nihilism involving lifestyle factors in older adults”. (3)
“It is still likely that lifestyle factors such as diet and physical activity have important roles in the prevention of cognitive decline, dementia and performance of the activities of daily living”, the editorial authors wrote.
Professor Jon Buckley, director of the Alliance for Research in Exercise, Nutrition and Activity at the University of SA, agreed, telling MJA InSight that the results of the studies were inconclusive.
He said the key to the effectiveness of physical activity and a healthy diet was initiating these changes in young adulthood, not waiting until later in life as these studies did.
“If you start exercising regularly and taking supplements when you have no cognitive impairment, this can better prevent cognitive decline from happening”, Professor Buckley said.
He said neither study administered the intervention in sufficient enough doses to have a real impact.
“If you are going to take supplements, you need to take a decent dose. And if you’re going to exercise, a few minutes per day will not be enough. [Ideally] doctors should recommend about 150 minutes of activity per week — but obviously this depends on the patient’s capacity.”
Professor Ibrahim told MJA InSight the JAMA research represented a growing interest in finding ways to improve quality of life as people aged. “We all want to not get dementia.”
He said with vascular dementia, certain risk factors were well recognised.
“We know that if you manage your weight, decrease you cholesterol levels and exercise, you can decrease your chance of stroke, which reduces your chance of getting vascular dementia.”
However, Professor Ibrahim said the true benefits of physical activity required further investigation.
“Some exercise brings people together to socialise in a community, so the benefits of physical activity might not come from what exercise is done, but how it is done. But at this stage, it is speculation.”
He said the medical community must also be cautious to avoid a similar situation that occurred with osteoporosis.
“With osteoporosis, we used to think we would be able to do something about it when people reached the age of 60. But then we realised that the damage had already been done years before.
“Likewise with cognitive function, intervention needs to start much earlier.”
Professor Ibrahim said education and awareness efforts needed to become more proactive in targeting adults under the age of 30 years.
“Most of the physiological changes happen before you turn 30, and after that things generally start to decline, that’s the natural process.”
(Photo: PedroMatos / shutterstock)