A healthy lifestyle and diet can help to slow down memory decline, a decade-long study of older adults in China reports today.
The research team led by the Capital Medical University, National Centre for Neurological Disorders, Beijing, found this was true even for carriers of the apolipoprotein E (APOE) gene, which is the strongest known risk factor for Alzheimer’s disease and related dementia.
Evidence from existing studies is insufficient to assess the effect of a healthy lifestyle on memory in later life, so to analyse this, the team followed 29,000 adults aged 60 and over with normal cognitive function who were part of the China Cognition and Aging Study. The average age of participants was 72 and 49% were women.
The study began in 2009 and memory function was measured using the Auditory Verbal Learning test (AVLT). Participants were also tested for the APOE gene and 20% were found to be carriers.
Researchers followed up the participants in 2012, 2014, 2016, and 2019, calculating a healthy lifestyle that combined six factors: healthy diet, regular exercise, active social contact, cognitive activity, non-smoking, and never drinking alcohol.
Participants were classed as “favourable” if they had four to six factors; “average” if they recorded two to three factors, or “unfavourable” if they recorded zero or one factor. They were also grouped into APOE carrier and non-carrier groups.
After accounting for a range of other health, economic and social factors, the researchers found each individual healthy behaviour was associated with a slower than average decline in memory over 10 years, with a healthy diet having the strongest effect on slowing memory decline, followed by cognitive activity and then physical exercise.
Participants with the APOE gene with favourable and average lifestyles also experienced a slower rate of memory decline than those with an unfavourable lifestyle.
Those with favourable or average lifestyles were almost 90% and almost 30% less likely to develop dementia or mild cognitive impairment relative to those with an unfavourable lifestyle. The APOE group had similar results.
Although this is an observational study, the authors say its size and long follow-up period. Their findings remained significant after further analyses, they add, which suggest they are robust.
They add further research could focus on the effects of a healthy lifestyle on memory decline across the lifespan. “These results might offer important information for public health initiatives to protect older adults against memory decline,” they conclude.
Jia J, Zhao T, Liu Z et al. Association between healthy lifestyle and memory decline in older adults: 10 year, population based, prospective cohort study. BMJ 26 January 2023; doi: 10.1136/bmj-2022-072691
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