Social isolation, loneliness increase risk for mortality

Key takeaways:

• Both social isolation and loneliness were linked to an increased risk for all-cause mortality and cancer mortality.
• Social isolation was also linked to an increased risk for CVD mortality.

Social isolation and loneliness were linked to an increased risk for all-cause and cause-specific types of mortality, according to a recent systematic review and meta-analysis published in Nature Human Behavior.

Previous research has identified both social isolation (SI) and loneliness as having associations with risks for several conditions, including type 2 diabetes, heart failure, myocardial infarction and stroke.

“However, no systematic review of an association of SI or loneliness with the risk of mortality in patient populations (for example, individuals with CVD or cancer) has been conducted,” Fan Wang, PhD, from the School of Public Health at Harbin Medical University in China, and colleagues wrote. “Our findings can provide vital clarification to help in promoting population health management and improving primary health services.”

For the systematic review and meta-analysis, the researchers examined 90 prospective cohort studies that were published between 1998 to 2022. Overall, 29 studies were conducted in the U.S., whereas 67 reviewed the risk for all-cause mortality.

The studies consisted of 2,205,199 individuals aged 18 years and older, with 70% of participants aged 50 years or older.

Wang and colleagues found that SI was associated with a pooled effect estimate of:

• 1.32 (95% CI, 1.26-1.39) for all-cause mortality risk;
• 1.24 (95% CI, 1.19-1.28) for cancer mortality risk; and
• 1.34 (95% CI, 1.25-1.44) for CVD mortality risk.

Additionally, the pooled effect estimate was a 1.28 (95% CI, 1.1-1.48) and 1.51 (95% CI, 1.34-1.7) for all-cause mortality risk in individuals with SI and CVD or breast cancer, respectively.

Meanwhile, loneliness was associated with pooled effect estimates of 1.14 (95% CI, 1.8-1.2) for all-cause mortality risk and 1.9 (95% CI, 1.1-1.17) for cancer mortality risk.

“SI and loneliness may be exacerbated by post-cancer or CVD stress and less social contact as well as limited access to care, especially informal care from friends and family,” they wrote.

Wang and colleagues noted that understanding gender differences in association with loneliness, SI and mortality could additionally help to improve gender equity.

“Generally, the prevalence of SI or loneliness varies by gender. Owing to differences in occupation, social position and physiological specificity, women are more susceptible to feelings of loneliness than men, but women have larger social networks than men, even later in life,” they wrote. “Living alone and having a lack of interpersonal connections seem particularly predominant and detrimental in men.”

Wang and colleagues acknowledged several limitations to the study. Because of the small number of participants who reported both high levels of SI and loneliness, there was a lack of analysis on the combined effect of the two conditions. Additionally, the results may have been influenced by certain factors, including premature deaths like suicide or self-harm.

The researchers concluded that strategies are needed to address public health concerns, “such as raising awareness about the adverse health effects of SI and loneliness among health care professionals and the general public.”

“The health care system should also develop methods to identify SI and loneliness in healthcare settings so that health care professionals can provide appropriate clinical and public health interventions,” they wrote.