Socially isolated older adults have a 27% higher chance of developing dementia than older adults who aren't, a new study by Johns Hopkins researchers found.

"Social connections matter for our cognitive health, and the risk of social isolation is potentially modifiable for older adults," Dr. Thomas Cudjoe, an assistant professor of medicine at Johns Hopkins and a senior author of the study, said in a news release.

Published in the Journal of the American Geriatrics Society, the study tracked 5,022 dementia-free U.S. adults who were 65 or older – with an average age of 76 – and not living in a residential care facility. About 23% of participants were socially isolated.

Social isolation is defined as having few relationships and few people to interact with regularly. The study measured this based on whether or not participants lived alone, talked about "important matters" with two or more people in the past year, attended religious services or participated in social events. Participants were assigned one point for each item, and those who scored a zero or one were classified as socially isolated.

Over the course of nine years, researchers periodically administered cognitive tests. Overall, about 21% of the study participants developed dementia. But among those were who were socially isolated, about 26% developed dementia – compared to slightly less than 20% for those who were not socially isolated.

The study did not find significant differences by race or ethnicity. However, more than 70% of the participants in the study were white – with particularly small sample sizes of Hispanic, Asian and Native participants – and the authors call for further research on the topic.

Social isolation has previously been known as a dementia risk factor and is linked to other serious health conditions such as heart disease and depression, according to the Centers for Disease Control and Prevention.

About 5.8 million people in the U.S. have Alzheimer's disease, which is the most common type of dementia, according to the CDC.

Social engagement can improve the quality of life for patients living with dementia and slow its progression.

A second study using related data found that access to technology such as cell phones can prevent social isolation among older adults.

"This is encouraging because it means simple interventions may be meaningful," Mfon Umoh, a postdoctoral fellow in geriatric medicine at Johns Hopkins, said in a news release.