Social Isolation, Loneliness Tied to CV Risk

Rosalind Stefanac

February 15, 2022

Well before the pandemic raised concerns around the health impacts of social distancing, isolation from others and feelings of loneliness have been shown to be contributing factors to higher rates of cardiovascular disease (CVD) in older adults.

Now, new research in older women in particular shows that isolation and loneliness are associated with an increased risk for a composite endpoint of major CVD, which includes heart disease, stroke, and death from cardiovascular disease.

The 8-year prospective cohort study, conducted from March 2011 to March 2019 in the United States, showed that social isolation and loneliness were associated with an increased risk for incident CVD in postmenopausal women by 8% and 5%, respectively, after adjustment for health behaviors and outcomes. For older women who experience high levels of both social isolation and loneliness, the increased risk was up to 27%. 

Results of the study were published in the February issue of JAMA Network Open.

Several previous trials have indicated that social isolation and loneliness are prevalent among older adults, and are associated with CVD risk factors, such as elevated blood pressure, cholesterol levels, obesity, smoking, physical inactivity, and poor diet.

Given that women make up the majority of older adults in the United States, targeting postmenopausal women was a particular area of interest. For this analysis, the researchers focused on women 65 to 99 years of age who had previously participated in the Women's Health Initiative Extension Study II and had no history of myocardial infarction (MI), stroke, or coronary heart disease.

Over the duration of the study, information was gathered from 57,825 women with an average age of 79 years. Participants responded to questionnaires designed to assess social isolation in 2011 or 2012, and then were sent a second questionnaire assessing loneliness and social support in 2014 or 2015. A total of 1599 CVD events occurred over 186,762 person-years of follow-up.

Results shows that social isolation and loneliness were tied to heightened CVD risk in this population, even after adjustment for behaviors that already affect cardiovascular health, such as smoking, poor diet, and sedentary lifestyle.

High vs low social isolation was associated with major CVD, with a hazard ratio of 1.18 (95% CI, 1.13 - 1.23). The hazard ratio for high vs low loneliness was 1.14 (95% CI, 1.10 - 1.18).

After additional adjustment for health behaviors and health status, those hazard ratios were 1.08 for social isolation (95% CI, 1.03 - 1.12) and 1.05 for loneliness (95% CI, 1.01 - 1.09).

"Women with both high social isolation and high loneliness scores had a 13.0% to 27.0% higher risk of incident CVD than did women with low social isolation and low loneliness scores," the authors report.

"This is a strong signal to us that there is some pathway that is causing higher levels of cardiovascular disease among people who are socially isolated and lonely," said coauthor John Bellettiere, PhD, MPH, assistant professor of epidemiology at the UC San Diego Herbert Wertheim School of Public Health. "I think further epidemiological investigation will go into understanding what those pathways are [so] we might be able to come up with alternate solutions."

The fact that social isolation and loneliness were also distinct factors for increasing CVD risk in this population group was another key study finding. "In my mind, those two things are almost the same, [yet] there are a lot of people who have high levels of social isolation but they're not lonely," said Bellettiere. "Understanding the whole dynamic between the lack of relationship between these two constructs — and that each of them are independently important in CVD in postmenopausal women — was a surprise."

Interestingly, social support was not a significant effect modifier of these associations, they note.

"I always thought social support would buffer any type of loneliness or isolation, but as we tested in the study, I don't think it functions that way," says lead author Natalie Golaszewski, PhD, a post-doctoral scholar at the Herbert Wertheim School of Public Health and Human Longevity Science. She cautioned that this could be due to the fact that too few women who were assessed had low levels of social support to see a modifying effect.

"Those women who were socially isolated and lonely also had poor health behaviors and health outcomes, so it warrants more research around what is the relationship between feeling [this way] and your behaviors," says Golaszewski.

Kathryn Rexrode, MD, MPH, chief of the Division of Women's Health, Department of Medicine, Brigham and Women's Hospital, Boston, noted that having a more granular look at the factors that affected study participants — such as race, economic status, and living conditions — would have been beneficial in determining different interventions to reduce social isolation and loneliness.

"If I think about my own patients and their different living conditions, there is a dramatic difference if you're a senior in assisted living with a lot of social interaction compared to someone alone in an apartment with poor physical function," she said. "I think we have to look at structural issues, including financial resources, that might contribute to social isolation and loneliness."

Where to From Here?

Given that there is a very clear relation between social isolation, loneliness, and poor health outcomes, including cardiovascular disease, the next step would be to focus on developing ways to identify people who are at risk, Rexrode said. "I do think this study stresses the need to think about effective interventions to reduce social isolation and loneliness, especially with our aging population."

Researchers say measuring social isolation and loneliness as part of standard primary care practice could go a long way in identifying patients at risk. They suggest asking a few simple questions around living conditions or creating an index score to get a pulse on a patient's social connection.

The National Institute on Aging has also developed a Social Isolation and Loneliness Outreach Toolkit. "This toolkit includes a whole host of ideas for supporting older adults in reducing social isolation and loneliness…and there may be some interventions that resonate," said Bellettiere.

Beyond social supports, there is potential for future treatments that could help patients at risk, he said. "I believe if we can isolate some of the physiologic pathways, interventions specifically tailored to that pathway could be developed, potentially alternative mechanisms that might be able to shift the levers that are contributing to cardiovascular disease."

The study was supported by unrestricted grants from the NIA, HIH, and National Institute of Diabetes and Digestion and Kidney Diseases. Bellettiere reported receiving grants from the Tobacco-Related Disease Research Program (TRDRP) during the conduct of the study, and personal fees from Meta outside the submitted work. Disclosures for coauthors appear in the published study.

JAMA Netw Open. 2022;5:e2146461. Full text

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