Study links lifestyle to rate of memory decline

A decadelong study of older adults in China has found that a healthy lifestyle is linked to slower memory decline even when people carry a risky gene for Alzheimer's.

Memory loss is a common part of aging. While there is no cure for most conditions that cause cognitive decline, lifestyle has received increasing attention as it is relatively easy to manage with potential benefits for overall health, including memory.

In a report in the latest issue of British Medical Journal, researchers from China's National Center for Neurological Disorders and other medical institutes followed 29,000 people aged at least 60 years with normal cognitive abilities for up to 10 years. Forty-nine percent of the participants were women.

The participants were from 12 provinces from the north, south and west of China, representing the geographical characteristics, degree of urbanization, economic status, dietary patterns, and cultural and social differences in China.

At the beginning of the study in 2009, the researchers tested participants' memory function with the Auditory Verbal Learning Test, one of the most widely used word-learning tests. They were also tested for the APOE gene, the most common gene linked with Alzheimer's. Around 20 percent of the participants were carriers of the risk gene.

The participants received assessments in 2012, 2014, 2016 and 2019. In the follow-ups, six healthy lifestyle factors were analyzed: a healthy diet (adherence to recommended food items), regular physical exercise (at least 150 minutes of moderate intensity or 75 minutes of vigorous-intensity exercises per week), active social contact (for example, seeing friends and family at least twice a week), active cognitive activity (for example, reading, writing, playing chess at least twice a week), non-smoking and never drinking alcohol.

Participants were categorized into the favorable group if they had four to six healthy lifestyle factors, an average group for two to three factors, and an unfavorable group for zero to one.

They were also divided into the APOE-carrier group and the non-carrier group.

During the 10-year follow-up, 7,164 participants died and 3,567 dropped out of the research for various reasons.

The results showed that the mean AVLT scores continuously declined over the 10 years. The highest test scores were in the favorable group and the lowest in the unfavorable group. The participants with favorable and average lifestyles, even when they were APOE carriers, had a slower rate of memory decline than the participants with unfavorable lifestyles.

Among the six factors, a healthy diet had the most substantial effect on memory, followed by an active cognitive activity, regular physical exercise, active social contact, never or formerly smoking and never drinking.

Meanwhile, the results also showed that a favorable lifestyle was associated with a 90 percent lower probability of progression to mild cognitive impairment and dementia. The number for the average group was 30 percent.

The researchers said that they studied the contribution of each lifestyle factor and their combined effects in a large sample size over an entire decade and offered important information to protect older adults against memory decline. The results about the APOE carriers also provide an optimistic outlook that healthy lifestyle risks are associated with a slower rate of memory decline, regardless of the genetic risk.

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