Nearly every study of volunteering and health shares the same weakness: the people who volunteer were healthier to begin with.
Take the meta-analysis by Okun and colleagues (Psychology and Aging. 2013;28(2):564-577), which found that older volunteers had a 24% lower risk of death from any cause than non-volunteers. That figure comes mostly from observational studies. You need to be able to get out of the house to volunteer, so it’s hard to tell whether volunteering built the health or healthy people simply signed up.
So has anyone assigned people to volunteer by lot?
A randomized trial in Baltimore
Yes. Carlson and colleagues reported the Baltimore Experience Corps trial in 2015 (Alzheimer’s & Dementia. 2015; PMID 25835516). Retired adults helped children learn in elementary school libraries and classrooms. A total of 111 people, average age 67.2, were randomly assigned to the program (58) or a control group (53) and followed for 24 months, with MRI scans to measure brain volume.
The control group’s brains shrank at the usual age-related pace. In the program group, men showed a small increase in brain volume, and the hippocampus, a region central to memory, held its size. Women in the program also showed small gains, but the difference was not statistically significant (the control group lost roughly 1% over 24 months). The authors also reported that people whose brain volume grew the most tended to improve the most on memory tests.
It was 111 people over two years. Too small to settle anything.
Japan’s REPRINTS program
In Japan, researchers have followed REPRINTS, an intergenerational program in which older adults read picture books to schoolchildren about once every one to two weeks.
In the study by Sakurai and colleagues (International Journal of Geriatric Psychiatry. 2017; doi:10.1002/gps.4785), participants had MRI scans at baseline and six years later. The analysis included 17 program members and 42 controls. Hippocampal volume fell in the control group and was maintained in the program group. The thalamus and caudate nucleus showed no difference, and cognitive test scores did not differ either. What the team did find was that bigger hippocampal losses went along with bigger cognitive declines.
This study was not randomized. People chose for themselves whether to join or serve as controls. And the numbers are small.
A Japanese government-funded research report covering ten years of follow-up (KAKENHI project 26330183, led by Naoko Sakuma) described group differences in verbal fluency and in immediate recall of a story. But by year ten, only 28.2% of the program group remained, compared with 46.5% of controls. If the people who stayed were the ones doing well, the results look better than they should, so I’d discount them accordingly.
What we can and can’t say
The U.S. randomized trial and the Japanese follow-up point the same way: older adults who stayed involved with children showed better preservation of hippocampal volume.
What the sources here don’t tell us is whether that preservation translated into fewer cases of dementia or sharper memory in daily life. In the Japanese study, cognitive scores did not differ. The size of any benefit, and how much depends on how often or how long someone takes part, remains unknown.
Social contact does get serious attention in dementia prevention. The Lancet Commission (Livingston et al., The Lancet. 2024;404:572-628) lists 14 modifiable risk factors and estimates that about 45% of dementia cases could be prevented or delayed by addressing them together. Social isolation is one of the 14. That 45% is the combined estimate for all of them, not a number you earn by seeing people more often.
My own view: the research doesn’t show that volunteering protects the brain. It shows that something with a regular schedule, a set place, and people who are expecting you is worth trying. You walk there, you talk, you have a job to do. Too many things are bundled together to tell which one matters, and that’s where this field stands.
In Japan, school reading and tutoring programs are usually arranged through your city’s social welfare council (shakai fukushi kyogikai) or your local school. If you have health concerns or a chronic condition, talk to your own doctor before starting something new.
For a broader look at movement, food, and community in the world’s longest-lived places, see my book Walking to 110: Kindle edition here.
References
- Okun MA, et al. Volunteering by older adults and risk of mortality: a meta-analysis. Psychology and Aging. 2013;28(2):564-577.
- Livingston G, et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. The Lancet. 2024;404:572-628.
- Carlson MC, et al. Impact of the Baltimore Experience Corps Trial on cortical and hippocampal volumes. Alzheimer’s & Dementia. 2015. PMID: 25835516.
- Sakurai R, et al. Preventive effects of an intergenerational program on age-related hippocampal atrophy in older adults: The REPRINTS study. International Journal of Geriatric Psychiatry. 2017. doi:10.1002/gps.4785.
- Japan Society for the Promotion of Science, KAKENHI project 26330183, 10-year longitudinal study of picture-book reading volunteer activity and cognitive function in older adults (FY2014-2018).