Loneliness and isolation linked to 5.8 fewer healthy years

A Tulane University observational study of 277,489 adults linked loneliness and social isolation to up to 5.8 fewer years free of depression and anxiety, according to a Nature Communications paper published Oct. 10.

Evidence grade: Moderate (consistent observational data or small trials). In the Oct. 10 Nature Communications study, Tulane researchers translated social connection measures into disease-free life expectancy, with men showing the largest mental-health difference.

The study examined adults aged 40 to 69 who initially did not have seven major chronic conditions: diabetes, heart disease, lung disease, dementia, cancer, depression and anxiety. Researchers used age 50 as the reference point for estimating years lived without those conditions.

“Overall, the study found that social isolation and loneliness can have a significant impact on disease-free life expectancy,” said Lu Qi, lead author and HCA Regents Distinguished Chair and professor at Tulane University’s Celia Scott Weatherhead School of Public and Tropical Medicine. “This includes both physical and mental disease.”

The paper treated social isolation and loneliness as related but different exposures. Social isolation was defined as a measurable lack of social connections, while loneliness referred to dissatisfaction with the quality of relationships, even when social contact exists.

The physical-health association was smaller than the mental-health association. Women reporting both loneliness and social isolation had 2.4 fewer years free from major physical disease, while men had 1.7 fewer years, compared with people reporting neither exposure.

“This comes down to the gender differences between men and women,” Qi said. “Our research found men are more susceptible to being affected by loneliness. We also know that women tend to live longer than men.

There are gender advantages with certain diseases.”

The study applies most directly to middle-aged and older adults in the 40-to-69 age range studied at baseline. The source text did not provide country composition, funding details or confidence intervals for the reported estimates.

The source text cited a 2023 report saying about half of U.S. adults experience loneliness and nearly as many are socially isolated. That background helps explain why researchers are trying to quantify the health burden in years, rather than only in relative risks.

The study cannot determine whether loneliness or social isolation were themselves responsible for the differences in healthy life expectancy. As an observational analysis, it can identify associations, while unmeasured factors may contribute to both social disconnection and later illness.

Lifestyle appeared to matter differently for the two exposures. Healthier patterns, including better diet, regular exercise, sufficient sleep and not smoking, were associated with a smaller loss of disease-free years among socially isolated people. The same pattern was not seen for loneliness, according to the Tulane summary.

The research team plans to study additional population groups and use clinical trials to test whether loneliness and social isolation are directly linked to the health effects observed in the analysis. No date was provided for those next studies.

Source: peer-reviewed study in Nature Communications; Tulane University/ScienceDaily summary, Oct. 10.

Atlas360 reports health research and does not provide medical advice.