Loneliness Is a Killer

Loneliness and social isolation are risk factors for both stroke and coronary heart disease (CHD), with stroke showing a slightly greater association, a study of past literature concludes.

The review, conducted by Nicole Valtorta, research fellow, of the Department of Health Sciences, at the University of York in Heslington, York, UK, and colleagues, was published in the journal Heart on April 18, 2016.

The researchers identified 23 longitudinal studies, based on 16 cohorts, which included 2002 stroke events and 4628 cases of CHD. The studies had follow up periods of 3 to 21 years. Of those studies, 3 measured loneliness, 18 measured social isolation, and 2 measured both.

“Across nine independent study samples (2577 events; one study did not report numbers), the average relative risk of stroke incidence was 1.32,” the researchers report. They found a 32% risk increase of stroke overall, and a 29% increase in risk of CHD for people who had poor social relationships, and say, “This is the first systematic review to focus on the prospective association between loneliness or social isolation and first occurrence of CHD or stroke.”

This review does have some limitations.

For example, because it is a review there is a risk of publication bias. On the other hand, the researchers say, “our pooled effects could be a conservative estimate.” They did not find any differences between genders, and say “our review included some data collected from 1965; more recent strategies for CHD prevention may have modified the influence of loneliness and social isolation on disease incidence.”

Even taking the possible limitations and biases into account, this is an important study because stroke and CHD are two of the leading causes of death in high-income countries.

If interventions designed to prevent loneliness and social isolation can effectively lower the risk of death from stroke or CHD, this study is a critical first step.

The researchers conclude, “Our findings suggest that tackling loneliness and isolation may be a valuable addition to CHD and stroke prevention strategies. Health practitioners have an important role to play in acknowledging the importance of social relations to their patients.”