Over-60s who enjoy a combination of healthy lifestyle choices like eating well, regularly exercising, playing cards and socialising at least twice weekly, are likely to have a reduced risk of dementia and slower memory decline, a decade-long study has suggested.
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. While previous research evidence has, until now, been insufficient to evaluate the effect of healthy lifestyle on memory trajectory, the recent study suggests that combining multiple healthy lifestyle choices – the more the better – is linked with retarding the speed of memory decline.
In their research published in The BMJ, the team from the National Centre for Neurological Disorders in Beijing, China, wrote that practising multiple healthy lifestyle choices “was associated with a lower probability of progression to mild cognitive impairment and dementia”, they added.
The Guardian reports that they analysed 29 000 adults over 60 with normal cognitive function who were part of the China Cognition and Ageing Study.
At the start of the study in 2009, memory function was measured using tests, and people were checked for the APOE gene, 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 the recommended intake of 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 that followed people over a long period, 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.”
Study details
Association between healthy lifestyle and memory decline in older adults: 10 year, population based, prospective cohort study
Jianping Jia, Tan Zhao, Zhaojun Liu, Yumei Liang, Fangyu Li, Yan Li, Jeffrey Cummings, et al.
Published in The BMJ on 25 January 2023
Abstract
Objective
To identify an optimal lifestyle profile to protect against memory loss in older individuals.
Design
Population based, prospective cohort study.
Setting
Participants from areas representative of the north, south, and west of China.
Participants
Individuals aged 60 years or older who had normal cognition and underwent apolipoprotein E (APOE) genotyping at baseline in 2009.
Main outcome measures
Participants were followed up until death, discontinuation, or 26 December 2019. Six healthy lifestyle factors were assessed: a healthy diet (adherence to the recommended intake of at least 7 of 12 eligible food items), regular physical exercise (≥150 min of moderate intensity or ≥75 min of vigorous intensity, per week), active social contact (≥twice per week), active cognitive activity (≥twice per week), never or previously smoked, and never drinking alcohol. Participants were categorised into the favourable group if they had four to six healthy lifestyle factors, into the average group for two to three factors, and into the unfavourable group for zero to one factor. Memory function was assessed using the World Health Organization/University of California-Los Angeles Auditory Verbal Learning Test, and global cognition was assessed via the Mini-Mental State Examination. Linear mixed models were used to explore the impact of lifestyle factors on memory in the study sample.
Results
29 072 participants were included (mean age of 72.23 years; 48.54% (n=14 113) were women; and 20.43% (n=5939) were APOE ε4 carriers). Over the 10-year follow-up period (2009-19), participants in the favourable group had slower memory decline than those in the unfavourable group (by 0.028 points/year, 95% confidence interval 0.023 to 0.032, P<0.001). APOE ε4 carriers with favourable (0.027, 95% confidence interval 0.023 to 0.031) and average (0.014, 0.010 to 0.019) lifestyles exhibited a slower memory decline than those with unfavourable lifestyles. Among people who were not carriers of APOE ε4, similar results were observed among participants in the favourable (0.029 points/year, 95% confidence interval 0.019 to 0.039) and average (0.019, 0.011 to 0.027) groups compared with those in the unfavourable group. APOE ε4 status and lifestyle profiles did not show a significant interaction effect on memory decline (P=0.52).
Conclusion
A healthy lifestyle is associated with slower memory decline, even in the presence of the APOE ε4 allele. This study might offer important information to protect older adults against memory decline.
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