A combination of healthy lifestyle choices such as eating well, regularly exercising, playing cards and socialising at least twice a week may help slow the rate of memory decline and reduce the risk of dementia, a decade-long study suggests.

Memory is a fundamental function of daily life that continuously declines as people age, impairing quality of life and productivity, and increasing the risk of dementia.

Evidence from previous research has been insufficient to evaluate the effect of healthy lifestyle on memory trajectory, but now a study suggests that combining multiple healthy lifestyle choices – the more the better – is linked with softening the speed of memory decline.

“A combination of positive healthy behaviours is associated with a slower rate of memory decline in cognitively normal older adults,” researchers from the National Center for Neurological Disorders in Beijing, China, wrote in the BMJ.

Practising multiple healthy lifestyle choices together “was associated with a lower probability of progression to mild cognitive impairment and dementia”, they added.

Researchers analysed 29,000 adults aged over 60 with normal cognitive function who were part of the China Cognition and Aging Study.

At the start of the study in 2009, memory function was measured using tests and people were checked for the APOE gene, which is the strongest risk-factor gene for Alzheimer’s disease. The subjects were then monitored for 10 years with periodic assessments.

A healthy lifestyle score combining six factors was calculated: a healthy diet; regular exercise; active social contact; cognitive activity; non-smoking; and not drinking alcohol.

Based on their score, ranging from zero to six, participants were put into lifestyle groups – favourable (four to six healthy factors), average (two to three healthy factors), or unfavourable (0 to 1 healthy factors) – and into APOE-carrier and non-carrier groups.

A healthy diet was deemed as eating at least seven out of 12 food groups: fruits, vegetables, fish, meat, dairy, salt, oil, eggs, cereals, legumes, nuts and tea.

Writing, reading, playing cards or other games at least twice a week was the second area of healthy behaviour.

Other areas included drinking no alcohol, exercising for more than 150 minutes a week at moderate intensity or more than 75 at vigorous intensity, and never having smoked or being an ex-smoker.

Social contact at least twice a week was the sixth healthy behaviour, including activities such as visiting family and friends, attending meetings or going to parties.

After accounting for factors likely to affect the results, the researchers found that each individual healthy behaviour was associated with a slower-than-average decline in memory over 10 years.

A healthy diet had the strongest effect on slowing memory decline, followed by cognitive activity and then physical exercise.

People with the APOE gene who had healthy lives on the whole also experienced a slower rate of memory decline than those with APOE who were the least healthy.

Overall, people with four to six healthy behaviours or two to three were almost 90% and almost 30% respectively less likely to develop dementia or mild cognitive impairment relative to those who were the least healthy, the BMJ reported.

Dr Susan Mitchell, head of policy at Alzheimer’s Research UK, said: “This is a well-conducted study, which followed people over a long period of time, and adds to the substantial evidence that a healthy lifestyle can help to support memory and thinking skills as we age.

“Too few of us know that there are steps we can all take to reduce our chances of dementia in later life.”