A study published in The BMJ found that older adults in China who maintain a healthy lifestyle, particularly a healthy diet, experience slower memory decline. The study, which lasted for a decade, also found that even carriers of the APOE gene, a strong risk factor for Alzheimer’s and related dementias, can slow memory loss by living a healthy lifestyle.
Researchers from the China Cognition and Aging Study analyzed data from 29,000 adults aged 60 or older, with an average age of 72 and 49% being women, to investigate the relationship between a healthy lifestyle and memory decline in later life. The study participants had normal cognitive function at the start and were tested for the APOE gene (20% were found to be carriers).
The memory function was measured using the Auditory Verbal Learning test (AVLT) and follow-up assessments were conducted over the next 10 years. The evidence from existing studies is not enough to determine the effect of a healthy lifestyle on memory decline as people age, and the study suggests that a combination of healthy behaviors may be necessary to achieve an optimal effect.
The researchers calculated a healthy lifestyle score by combining six factors: a healthy diet, regular exercise, active social contact, cognitive activity, non-smoking, and abstaining from alcohol. Participants were then divided into three groups based on their score: favorable (4-6 healthy factors), average (2-3 healthy factors), and unfavourable (0-1 healthy factors) lifestyle groups and APOE carrier and non-carrier groups.
After accounting for various health, economic, and social factors, the researchers found that each individual healthy behavior was associated with a slower than average decline in memory over the 10-year study period.
The study found that a healthy diet had the strongest effect on slowing memory decline, followed by cognitive activity and physical exercise.
Participants in the favorable lifestyle group had a 0.28 point slower decline in memory over 10 years compared to the unfavourable group, and those in the average group had a 0.16 point slower decline.
Participants with the APOE gene who had favorable or average lifestyles also experienced a slower rate of memory decline than those with an unfavourable lifestyle.
Furthermore, those with favorable 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, and the APOE group had similar results.
This was a large study with a long follow-up period, allowing for evaluation of individual lifestyle factors on memory function over time.
The researchers suggest their results provide strong evidence that adherence to a healthy lifestyle with a combination of positive behaviors is associated with a slower rate of memory decline, even for people who are genetically susceptible to memory decline.