The link between loneliness and dementia has been quantified by analyzing data from more than 600,000 people around the world—the largest study of its kind. Researchers at Florida State University College of Medicine conducted a meta-analysis of 21 longitudinal studies. Their work showed that experiencing feelings of loneliness increased the risk of developing dementia by 31%.
The research was published in Nature Mental Health. The lead author is assistant professor Martina Luchetti, PhD.
“These results are not surprising, given the mounting evidence that links loneliness to poor health,” said Luchetti. “Dementia is [a] spectrum, with neuropathological changes that start decades before clinical onset. It is important to continue studying the link of loneliness with different cognitive outcomes or symptoms across this spectrum. Loneliness—the dissatisfaction with social relationships—may impact how you are functioning cognitively, and in daily life.”
Dementia is a term that describes several diseases that affect memory, thinking, and the ability to perform daily activities. It typically affects older people and gets worse over time. According to the World Health Organization, currently more than 55 million people have dementia worldwide, over 60% of whom live in low- and middle-income countries. Every year, there are nearly 10 million new cases.
Dementia is the seventh leading cause of death and one of the major causes of disability and dependency among older people globally. Alzheimer’s disease is the most common form of dementia and may contribute to 60–70% of cases.
This team’s large meta-analysis revealed that loneliness is a major risk factor for cognitive impairment, independent of age or sex. It also linked loneliness to specific causes of dementia, such as Alzheimer’s disease, and cognitive impairments that can occur before a diagnosis.
The team’s work was spurred by the World Health Organization and U.S. Surgeon General, who declared loneliness a public health crisis in the wake of the COVID-19 pandemic and its associated social restrictions.
“There has been a lot of interest in the consequences of loneliness for health,” Luchetti said. “It is important to understand why and under what circumstances it increases risk for late-life dementia.”
Data for the study included subjects from around the world, but most of it was collected from people in wealthier Western Hemisphere cultures. Future research should incorporate more data from other countries, Luchetti said.
“We know there are rising cases of dementia in low-income countries. Future studies need to gather more data from those countries to evaluate what are the effects of loneliness in different national and cultural contexts.”
The researchers believe the meta-analysis results provide information that can guide future prevention and intervention efforts.
“Now that there is solid evidence of an association, it is critical to identify the sources of loneliness to both prevent or manage loneliness and support the well-being and cognitive health of aging adults,” Luchetti added.
