A recent study has found a correlation between social isolation and reduced overall brain volume in older adults. While the research does not establish a causal relationship between social isolation and brain shrinkage, it highlights a concerning association. Toshiharu Ninomiya, the study's author from Kyushu University in Fukuoka, Japan, expressed concerns about the growing issue of social isolation among the elderly. He suggests that supporting individuals in establishing and maintaining social connections could potentially be beneficial in preventing brain atrophy and the onset of dementia.
The study involved 8,896 participants with an average age of 73, all of whom were free from dementia. The participants underwent MRI brain scans and health examinations. To assess social contact, the researchers asked a simple question: "How often are you in contact with relatives or friends who do not live with you (e.g., meeting or talking on the phone)?" The available response options ranged from every day to seldom.
The results, published in the journal Neurology, revealed that individuals with the least amount of social contact exhibited significantly lower overall brain volume compared to those with more frequent social interactions. The total brain volume, which includes both white and grey matter, as a percentage of the total intracranial volume, was 67.3 percent in the group with minimal contact, compared to 67.8 percent in the group with the highest level of social contact. Furthermore, the socially isolated participants showed reduced volumes in specific brain regions, such as the hippocampus and amygdala, which play vital roles in memory and are susceptible to dementia.
The study also found that symptoms of depression partially explained the relationship between social isolation and brain volumes. However, these symptoms accounted for only 15 percent to 29 percent of the observed association.
The researchers took various factors into account that could potentially influence brain volume, such as age, diabetes, smoking, and exercise habits. Additionally, the socially isolated individuals displayed a higher prevalence of small brain lesions known as white matter lesions.