Social isolation and loneliness and mortality among cancer survivors: a prospective cohort study.

BACKGROUND

Social isolation and loneliness are associated with mortality, but their impact on cause-specific mortality in cancer survivors remains unclear.

METHODS

This cohort study enrolled UK Biobank participants with cancer at baseline, followed up from March 2006 to September 2024. Social isolation and loneliness were assessed by self-reported questionnaires. Outcomes included all-cause, cancer-specific, and cardiovascular disease (CVD)-related mortality. Associations were evaluated using Cox proportional hazards models.

RESULTS

A total of 32,524 participants were included in this study (60.2% women; mean age, 60.3 years). During a median 15.7-year follow-up, 5,945 deaths occurred. Social isolation was significantly associated with increased all-cause (HR, 1.22; 95%CI, 1.12-1.32), cancer-specific (HR, 1.16; 95%CI, 1.04-1.28), and CVD-related (HR, 1.32; 95%CI, 1.07-1.63) mortality. Loneliness was not associated with all-cause mortality (HR, 0.98; 95%CI, 0.93-1.04), but independently associated with increased CVD-related mortality (HR, 1.26; 95%CI, 1.08-1.47). Exploratory analyses identified distinct prognostic impacts of specific isolation measures: living alone was linked to higher all-cause and non-cancer mortality across most cancer types, while weekly social activities and monthly family/friends visits were protective.

CONCLUSIONS

Social isolation was associated with increased risks of all-cause, cancer-specific, and CVD-related mortality. Loneliness was associated with elevated CVD-related mortality.