Helping others slows down the decline in cognitive functions

The study focused on the APOE ε4 gene variant — it is considered the most significant genetic risk factor for the late‑onset form of Alzheimer’s disease and is associated with a faster decline in cognitive abilities. The authors analysed data from nearly 18,000 adult residents of the USA over 22 years (from 1998 to 2020), collected as part of the nationally representative Health and Retirement Study. Scientists tracked how the cognitive performance of participants changed depending on whether they started or stopped helping others outside the home, and they took into account demographic, socio‑economic, and medical characteristics that can influence the rate of brain aging.

In people with the highest genetic risk who started and continued to help others, cognitive decline proceeded noticeably more slowly. According to researchers, such people reached the same level of pronounced cognitive impairment on screening tests almost two years later than those who were not involved in such activities. At the same time, the benefits were observed even with a relatively small workload: on average, less than four hours per week spent on volunteering or informal assistance was sufficient.

The type of assistance also played an important role. Formal volunteering was associated with a slowing of cognitive decline across all racial and ethnic groups. Informal assistance, such as support from loved ones, friends, and neighbors, had a particularly pronounced effect among older Latin Americans; researchers believe this may be due to the cultural significance of mutual support in these communities.

According to the lead author of the study, Se Hwan Han, very few pharmaceutical or behavioral approaches have so far demonstrated the ability to slow down the decline caused specifically by this gene variant. In this context, helping others—that is, free and accessible behavior—was found to be associated with significantly slower cognitive decline in the group at increased risk.

Although previous studies have already shown a link between prosocial activity and the slowing of age‑related decline in cognitive functions, the new study is one of the first to examine this link specifically in the context of the APOE ε4 gene. At the same time, the mechanisms behind this effect have not been directly studied: previously, it was assumed that helping others could influence biological processes related to stress and inflammation, which, in turn, are involved in cognitive decline.

Thus, the ability to contribute to the lives of other people may become an important element of a strategy for healthy aging, especially for those who are at increased genetic risk of developing Alzheimer’s disease.