Improving Social Isolation, Loneliness Reduces Obesity-Related Mortality Risk

Lu Qi, MD, PhD

Credit: Tulane University

Improvement to social isolation and loneliness indexes may attenuate the excess risk of mortality faced by people with obesity, according to a new cohort study.¹

As an escalating global crisis, people with obesity face excess risks of mortality and cardiovascular disease (CVD) but also exhibit markedly higher levels of social isolation and loneliness than people without obesity.

Among nearly 400,000 participants in the UK Biobank database, the risk of all-cause mortality decreased by 36% and 9% as indexes of social isolation and isolation went from highest to lowest among people with obesity, compared with those without the disease.

“Addressing social isolation and loneliness in individuals with obesity may potentially help improve unhealthy lifestyles, provide better psychological support, and encourage people at high risk to seek medical assistance, when necessary,” wrote the investigative team, led by Lu Qi, MD, PhD, from the department of epidemiology at Tulane University School of Public Health and Tropical Medicine.

Social isolation is the amount of social interaction observed in behavior, while loneliness relates to emotional experiences correlated with the quality of social relationships. Prior evidence has linked these factors of social determinants of health to raised mortality risks. However, no prospective study has evaluated whether improvements to isolation and loneliness would reduce obesity-related excess mortality risks.

Qi and colleagues investigated whether improving these factors would lower excess obesity-related mortality risk among those with and without obesity. The analysis separated people without cancer or CVD into cohorts based on a body mass index (BMI) of ≥30 for obesity or <30 for non-obesity, respectively. They assessed social isolation and loneliness indexes through self-reported questionnaires in the UK Biobank.

Based on the questionnaire, social isolation status was categorized as isolation (index ≥2) and non-isolation (index <2), and loneliness status was categorized as loneliness (index 2) and non-loneliness (index <2). All-cause, cancer-related, and CVD-related mortality were the primary outcomes for the analysis. Investigators defined the end of follow-up as the date of baseline to death or the censoring date in November 2021, whichever occurred first.

Overall, the analysis included 398,972 participants (mean age, 55.85 years; 220,469 [55%] women), of whom 93,357 (23%) had obesity, and 305,615 (77%) did not have obesity. According to the analysis, the prevalence of social isolation and loneliness in people with obesity was significantly higher than that in people without obesity (P < .001). During the median follow-up of 12.73 years, investigators recorded a total of 22,872 incident deaths.

Upon analysis, multivariable-adjusted models revealed hazard ratios (HRs) for all-cause mortality were 0.85 (95% CI, 0.79 - 0.91) and 0.74 (95% CI, 0.69 - 0.80) among those with obesity and social isolation index of 0 or 1, respectively (P for trend ≤.001), compared with a ≥2 social isolation index. The analysis showed similar results for cancer-related and CVD-related mortality.

For the loneliness metrics, the HRs for all-cause mortality were 0.97 (95% CI, 0.89 - 1.06) and 0.86 (95% CI, 0.79 - 0.94) for participants with obesity and a loneliness index of 1 and 0 (P for trend <.001), compared with those with obesity and loneliness index of 2. Qi and colleagues observed similar results among a population without obesity.

The multivariable model revealed the hazard ratios for all-cause mortality decreased as the indexes of social isolation and loneliness went from highest to lowest in those with obesity compared to those without obesity. Overall, Qi and colleagues found social isolation ranked in a higher spot than loneliness, depression, anxiety, and lifestyle-related risk for estimating the risk of all-cause mortality, cancer-related mortality, and CVD-related mortality.

“Our results suggest that improvement of social isolation may provide more benefits for reducing risks of all-cause mortality and CVD mortality than loneliness in people with obesity,” they wrote.

References

1. _{Zhou J, Tang R, Wang X, Li X, Heianza Y, Qi L. Improvement of Social Isolation and Loneliness and Excess Mortality Risk in People With Obesity. JAMA Netw Open. 2024;7(1):e2352824. doi:10.1001/jamanetworkopen.2023.52824}
2. _{Hajek A, Kretzler B, König HH. The Association Between Obesity and Social Isolation as Well as Loneliness in the Adult Population: A Systematic Review. Diabetes Metab Syndr Obes. 2021;14:2765-2773. Published 2021 Jun 17. doi:10.2147/DMSO.S313873}