Studies have shown that social isolation and loneliness are important risk factors for cardiovascular disease, but less has been known about their specific connection with heart failure.

A new study published in the journal JACC: Heart Failure shows that both social isolation and loneliness are associated with higher rates of heart failure. However, it appears that whether or not a person feels lonely is more important in determining risk than whether they are actually alone.

“Social isolation” as used here refers to being objectively alone or having infrequent social connections. Meanwhile, “loneliness” is defined as a painful feeling caused when someone’s actual level of social interaction is less than they would like it to be.

For the study, researchers looked at health outcomes for a population of more than 400,000 middle-aged and older adults. They used data from the UK Biobank study, which followed population health outcomes over 12 years and assessed psychosocial factors like social isolation and loneliness through self-reported questionnaires. 

The researchers found that both social isolation and loneliness increased the risk of hospitalization or death from heart failure by 15% to 20%. However, they also found that social isolation was only a risk factor when loneliness was not also present.

In other words, if a person was both socially isolated and felt lonely, loneliness was more important. Loneliness also increased risk even if the person was not socially isolated. Loneliness and social isolation were more common in men and were also associated with adverse health behaviors and status, such as tobacco use and obesity.

One reason for these findings might be because people can feel lonely even when they are in relationships or interact with others.

These findings indicate that the impact of subjective loneliness was more important than that of objective social isolation. Loneliness is likely a stronger psychological stressor than social isolation because loneliness is common in individuals who are hostile or have stressful social relationships.

The relationship of heart failure with social isolation and loneliness appears strongest in persons at extremes of social isolation & loneliness and compounded by low socioeconomic status.

For future studies, researchers plan to investigate the impacts of social isolation and loneliness on major health outcomes in vulnerable populations, including patients with Type 2 diabetes, and they are also working on experimental studies to better understand the mechanisms through which social isolation and loneliness affect cardiovascular health.