Alzheimer’s disease and related dementias (ADRD) cost patients, caregivers and society about $1 trillion per year worldwide. And the costs will only keep growing as people continue to live longer. In fact, researchers believe the number of ADRD cases will triple by 2050.

Studies have found social isolation is strongly associated with ADRD risk, but less is known about the association between isolation and other health and lifestyle factors that put people at risk for Alzheimer’s disease and related dementias. A recent study looked into that connection.

A team, led by researchers at McGill University in Montreal, Canada, found that feelings of loneliness and inadequate social support are associated with many of the health and lifestyle risk factors of Alzheimer’s disease and related dementias. Social risk factors like loneliness are more easily modified than genetic or other risk factors, making them a good potential target for preventing dementias.

People who exercised regularly with others had about a 20 percent decreased risk of feeling lonely and an almost 27 percent decreased risk of having an inadequate social support network.

Data from more than 500,000 participants in the U.K. Biobank and more than 30,000 participants in the Canadian Longitudinal Study of Aging were analyzed for the study. Participants in both studies filled out surveys that included questions about their social support network, feelings of loneliness and their frequency of social interaction.

Many lifestyle factors can increase a person’s social isolation. Smoking and drinking too much alcohol, sleep disturbances and not getting enough exercise are all aspects of a person’s lifestyle that have been found to be associated with feelings of loneliness and lack of social support.

People in the study who exercised regularly with others had about a 20 percent decreased risk of feeling lonely and an almost 27 percent decreased risk of having an inadequate social support network, both of which could help reduce the risk of cognitive decline.

Diabetes, cardiovascular disease, poor vision and hearing, and anxiety and depression were among the health-related risk factors linked to feelings of loneliness and inadequate social support that were also associated with Alzheimer’s disease and dementia.

For example, among participants in the U.K. Biobank, the inability to hear others over background noise was associated with a 29 percent increased risk of feeling lonely and an almost 10 percent increased risk of inadequate social support. Unsurprisingly, emotional volatility and susceptibility to stress were associated with an almost four times higher risk of loneliness and a 1.4 times greater risk of lacking social support.

The study focused on dementia in general, not just on Alzheimer’s disease. Future studies may explore how different combinations of health and lifestyle risk factors for ADRD affect their association with social risk factors. The authors write, “In line with recent research on different biomarker combinations in individual ADRD prognosis, our results open the possibility for individual differences in combinations of ADRD risk markers.”

The study is published in PLOS One.