It is important to prevent and slow age-related memory decline in older adults. Studies have been conducted to identify factors that might affect memory, including aging, the apolipoprotein E (APOE) ε4 genotype, chronic diseases, and lifestyle practices. Lifestyle, a modifiable behavior, has become the focus of research that addresses its potential benefits for overall health. However, fewer studies have focused on lifestyle’s effect on memory, and most of those were cross sectional in nature.
A recently published study done in China (Jia J, Zhao T, Liu Z, Liang Y, Li F, Li Y et al., 2023) sought to identify an optimal lifestyle profile designed to protect against memory loss in older adults. Overall, the researchers enrolled 29,072 with normal cognitive function who underwent APOE genotyping at baseline. The participants who were aged 60 years or older (mean age of 72.23 years) had normal cognition and were followed for 10 years (unless they dropped out (3,567) or died (7164).
Researchers assessed diet (a healthy one meant adherence to at least 7 to 12 eligible foods), physical exercise of either 150 minutes of moderate or 75 minutes of vigorous per week, and socialization at least two times per week. Additional lifestyle practices assessed were cognitive activity (writing, reading, playing cards, mahjong, and other games more than two times per week), nonsmokers (or previous smokers who had quit), and non-drinkers of alcohol.
Participants were categorized into three groups based on how many of the healthy lifestyle factors they had. The favorable group had four to six, the average group had two to three, and the unfavorable group had zero to one factor. Memory function and global cognition were assessed, and linear mixed models were used to explore the impact of lifestyle factors on memory in the participants.
Over the 10-year follow-up period (2009-19), participants in the favorable group had slower memory decline than those in the unfavorable group. APOE ε4 carriers with favorable and average lifestyles exhibited slower memory decline than those with unfavorable lifestyles. Among people who were not carriers of APOE ε4, similar results were observed among participants in the favorable and average groups compared with those in the unfavorable group. APOE ε4 status and lifestyle profiles did not show a significant interaction effect on memory decline.
This study investigated the contribution of each lifestyle factor and their combined effects in a large sample size over an entire decade. They found that diet had the strongest association with memory, followed by cognitive activity, physical exercise, and social contact. Although each lifestyle factor contributed differentially to slowing memory decline, the results showed that participants who maintained more healthy lifestyle factors had a significantly slower memory decline than those with fewer healthy lifestyle factors. This study also provided evidence that these effects include individuals with the APOE ε4 allele.
The results of this research provide evidence that memory loss is potentially modifiable and could be useful in guiding personal choices which can help protect against memory decline. Although the mechanisms responsible for such changes were not determined in this study, they might include reduced cerebrovascular risk, enhancement of cognitive reserve, inhibition of oxidative stress and inflammation, and promotion of neurotrophic factors.