Last updated on February 7th, 2023 at 01:42 pm
Another peer-reviewed paper has been published that concludes that certain lifestyle choices can reduce memory decline. Memory decline is not always related to dementia or Alzheimer’s disease, it can merely be senescent forgetfulness, which does not progress to a pathologic state.
In the paper, the researchers describe six lifestyle choices that seem to have a clinically significant effect on reducing memory decline. As you know, I like to review these types of papers and give them a star rating — let’s do the same here.
Reducing memory decline paper
In an article published on 25 January 2023 in The BMJ, Jianping Jia and colleagues examined the effect of various lifestyle choices on the rate of memory decline in 29,072 participants between 2009 and 2019. The researchers used the Mini–Mental State Examination was used to assess global cognitive function. Memory function was assessed using the World Health Organization/University of California–Los Angeles Auditory Verbal Learning Test.
The study group had an average age of 72.23 years, included 48.54% women, and 20.43% were APOE4 carriers, a gene implicated in Alzheimer’s disease. The study examined the following lifestyle choices:
- Physical exercise (weekly frequency and total time)
- Smoking (current, former, or never-smokers)
- Alcohol consumption (never drank, drank occasionally, low to excess drinking, and heavy drinking)
- Diet (daily intake of 12 food items: fruits, vegetables, fish, meat, dairy products, salt, oil, eggs, cereals, legumes, nuts, tea)
- Cognitive activity (writing, reading, playing cards, mahjong, other games)
- Social contact (participating in meetings, attending parties, visiting friends/relatives, traveling, chatting online)
Participants were scored based on the number of healthy lifestyle choices they engaged in.
- A “favorable” lifestyle included 4-6 lifestyle choices, n=5,556
- An “average” lifestyle included 2-3 lifestyle choices, n=16,549
- An “unfavorable” lifestyle included 0-1 lifestyle choices, n=6,967
Here is the list of lifestyle factors from the highest protective effect on memory decline to the lowest:
- Healthy diet, β =0.016
- Active cognitive activity, β=0.010
- Regular physical exercise, β=.007
- Active social contact, β=0.004
- Never/former smoker, β=0.004
- Never alcohol, β=0.002.
The last two did not show statistically significant differences. Furthermore, APOE4 carriers with favorable and average lifestyles showed slower memory decline compared to those with unfavorable lifestyles. This result alone could show that individuals at higher risk of Alzheimer’s disease can benefit from employing more favorable lifestyle choices to reduce the rate of memory decline.
Those with favorable or average lifestyle choices were respectively almost 90% and 30% less likely to develop dementia, compared to those with an unfavorable lifestyle.
Like my complaints about a lot of nutritional studies, these results depend upon self-reporting of lifestyle factors. The researchers are following each participant 24 hours a day to see if they exercise or eat a healthy diet.
This is an observational study, which means that there is no randomization or blinding of the participants and researchers like we might see in a clinical trial. Furthermore, confounders could influence the results — for example, maybe people who choose a healthy diet just happen to have a lower risk of memory decline.
The study also didn’t include wide demographic and ethnic groups, as it was run completely in China. A study like this would need to be repeated across numerous ethnic and demographic groups.
Finally, a lot of people dropped out of the study (either by choice or through death), which could have caused unintentional bias in the results.
My star rating
I like this study because of its size and thorough statistical analysis. That being said, it’s still an observational study with a lot of limitations that we see in this kind of study.
Unscientifically, I have a feeling that these choices probably do have a significant effect on memory decline, because there is a lot of data from other studies that show that these lifestyle choices have a positive effect on memory decline from aging, Alzheimer’s disease, and dementia.
I’m giving this study 3.5 out of 5 stars. Nevertheless, a healthy diet and regular exercise seem to have substantial benefits for numerous conditions, so I’m strongly in support of that.
- Jia J, Zhao T, Liu Z, Liang Y, Li F, Li Y, Liu W, Li F, Shi S, Zhou C, Yang H, Liao Z, Li Y, Zhao H, Zhang J, Zhang K, Kan M, Yang S, Li H, Liu Z, Ma R, Lv J, Wang Y, Yan X, Liang F, Yuan X, Zhang J, Gauthier S, Cummings J. Association between healthy lifestyle and memory decline in older adults: 10 year, population based, prospective cohort study. BMJ. 2023 Jan 25;380:e072691. doi: 10.1136/bmj-2022-072691. PMID: 36696990; PMCID: PMC9872850.