More than 55 million people live with dementia worldwide, according to figures from the World Health Organization. In 60 to 70% of cases, Alzheimer’s disease is the cause. But this term covers several diseases that affect memory, thinking, and the ability to perform everyday tasks. Currently, dementia is the seventh leading cause of death. If there is no cure for it, it is important to identify it as early as possible so that the quality of life of patients and their loved ones can be improved.
Japanese researchers have studied the brains of people with dementia. According to a study published on July 12, 2023, older people who have few social contacts are more likely to have brain volume loss in areas of the brain affected by dementia. These findings were published online in Neurology, the medical journal of the American Academy of Neurology. However, the scientific team emphasizes that these findings do not prove that social isolation causes brain shrinkage but only reveal an association.
“Social isolation is a growing problem for older people. These results suggest that providing support to people to help them establish and maintain relationships with others may be beneficial in preventing brain atrophy and the development of dementia,” study author Toshiharu Ninomiya said. , from Kyushu University, Fukuoka, Japan.
This study was conducted among 8,896 people with an average age of 73 and without dementia. All have had brain MRIs and various health exams. The researchers wanted to determine each participant’s level of social connection. To do this, they asked the panel the following question: “How often do you have contact with relatives or friends who do not live with you (for example by meeting or talking on the phone)?” Everyone was free to answer and could choose from the options “every day”, “several times a week”, “several times a month” or “rarely”.
Results ? Researchers found that those with the least amount of social contact had significantly lower overall brain volume. “The total volume of the brain, or the sum of white and gray matter, as a percentage of the total intracranial volume, or the volume inside the skull, including the brain, meninges, and cerebrospinal fluid, was 67.3% in the lowest contact group compared to 67.8% in the highest contact group,” the team reports. Before completing: “The volume of white matter lesions increased significantly with lower frequency of social contact (0.30% in the lowest frequency group, compared to 0.26% in the frequency group the highest). A lower frequency of social contact was associated with smaller volumes in the temporal lobe, occipital lobe, cingulum, hippocampus, and amygdala. Other factors were taken into account, such as smoking or diabetes.
Importantly, the researchers found that symptoms of depression explained – in part – the relationship between social isolation and brain volumes. However, symptoms of depression accounted for only 15-29% of the association. “Although this study is a snapshot in time and does not determine that social isolation causes brain atrophy, some studies have shown that exposure of older adults to socially stimulating groups halts or even reverses the decline in brain volume and improved thinking and memory skills,” adds the Japanese researcher.