A new study led by faculty at Florida State University College of Medicine has quantified the link between loneliness and dementia by analyzing data from over 600,000 individuals worldwide, making it the largest study of its kind.
The meta-analysis of 21 longitudinal studies showed that experiencing feelings of loneliness increased the risk of developing dementia by 31%.
“These results are not surprising, given the mounting evidence that link loneliness to poor health,” said Assistant Professor Martina Luchetti, who led the study. “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.”
Loneliness as a Major Risk Factor
The 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 the 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 the risk for late-life dementia.”
Need for Broader Research
Although data for the study included subjects from around the world, 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,” she said. “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 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 said.
The research was published in Nature Mental Health.
