A combination of different healthy lifestyle habits such as being physically active, not smoking and a high-quality diet can reduce the risk of developing Alzheimer's.

Researchers from the Rush University Medical Center examined data on nearly 3,000 people from two longitudinal studies run by the National Institute for Aging.

They found that people in the dataset who adhered to four or five 'healthy behaviour' types had a 60 per cent lower chance of developing Alzheimer's disease.

These included being physically active, not smoking, light-to-moderate alcohol consumption, eating a high-quality diet, and performing cognitive activities.

The National Institute on Aging (NIA) funded research adds to existing evidence that lifestyle factors play a part in mitigating Alzheimer's disease risk, the team said.

'The findings strengthen the association between healthy behaviors and lower risk,' said NIA Director Richard J. Hodes, M.D.

He said they 'add to the basis for controlled clinical trials to directly test the ability of interventions to slow or prevent development of Alzheimer's disease.'

The research team reviewed data from the Chicago Health and Aging Project (CHAP) and the Memory and Aging Project (MAP) longitudinal studies.

They selected participants from those studies who had data available on their diet, lifestyle factors, genetics, and clinical assessments for Alzheimer's disease.

The resulting data pool included 1,845 participants from CHAP and 920 from MAP.

The researchers scored each participant based on five healthy lifestyle factors, all of which have important health benefits.

This included undertaking at least 150 minutes per week of moderate-to-vigorous physical activity, not smoking and light-to-moderate alcohol consumption.

Other factors they were scored on included eating a high-quality Mediterranean diet and engagement in cognitive activities - such as chess - that keep the mind active.

The research team then compared the scores with outcomes of clinical diagnosis of Alzheimer's in the CHAP and MAP participants.

Lead author of the paper, Klodian Dhana, M.D., Ph.D., assistant professor at Rush University Medical Center, said the combination of healthy lifestyle factors is key.

He wrote that compared to participants with no or one healthy lifestyle factors, the risk of Alzheimer's was 37 per cent lower in those with two to three, and 60 per cent lower in those with four to five healthy factors.

'This population-based study helps paint the picture of how multiple factors are likely playing parts in Alzheimer's disease risk,' said Dallas Anderson, Ph.D., program director in the Division of Neuroscience at NIA.

'It's not a clear cause and effect result, but a strong finding because of the dual data sets and combination of modifiable lifestyle factors that appear to lead to risk reduction.'

In 2017 an NIA studied found that evidence on lifestyle factors along with blood pressure management and brain training was 'encouraging but inconclusive' for preventing or delaying the onset of Alzheimer's.

Since then, more research has emerged which suggests intensive blood pressure control may slow age-related brain damage.

There are a number of new trials currently underway including a clinical trial comparing two parellell groups with two different diets.

Another study is evaluating whether lifestyle interventions, including new diets, could protect cognitive functions in older adults at increased risk of decline.

NIA says it is currently funding more than 230 active clinical trials on Alzheimer's and related dementias to better understand the disease.

Of those, more than 100 are non-drug interventions, such as exercise, diet, cognitive training, sleep, or combination therapies.

This research was published in the June 17, 2020, online issue of Neurology, the medical journal of the American Academy of Neurology.