Loneliness and Mortality Risk Among Cancer Survivors in the United States: A Retrospective, Longitudinal Study

Background: Loneliness, a subjective feeling of being isolated, is a prevalent concern for elderly people and more so among cancer survivors because a cancer diagnosis and its subsequent treatment may result in long-term adverse health effects. This study aimed to examine the association of loneliness and mortality risk among cancer survivors in the United States. Methods: We identified a longitudinal cohort of cancer survivors aged ≥50 years from the nationally representative panel surveys of the 2008–2018 Health and Retirement Study. Follow-up for vital status was through 2020. Loneliness was measured using an 11-item abbreviated version of the UCLA Loneliness Scale (Version 3), including questions about lacking companionship and feeling isolated from others. A score was assigned according to the responses to each question, with 1 for least lonely, 2 for moderately lonely, and 3 for the loneliest option. Items were summed to create total loneliness scores for each individual, which were categorized into 4 levels: 11–12 (low/no loneliness), 13–15 (mild loneliness), 16–19 (moderate loneliness), and 20–33 (severe loneliness) based on the sample distribution. Time-varying Cox proportional hazard models with age as a time scale were used to examine the association of loneliness and survival among cancer survivors. Results: A total of 3,447 cancer survivors with 5,808 person-years of observation were included, with 1,402 (24.3%), 1,445 (24.5%), 1,418 (23.6%), and 1,543 (27.6%) reporting low/no, mild, moderate, and severe loneliness, respectively. Compared with survivors reporting low/no loneliness, survivors reporting greater loneliness had a higher mortality risk, with the highest adjusted hazard ratios (aHRs) among the loneliest group (aHR, 1.67 95% CI, 1.25–2.23; P =.004) following a dose–response association. Conclusions: Elevated loneliness was associated with a higher mortality risk among cancer survivors. Programs to screen for loneliness among cancer survivors and to provide resources and support are warranted, especially considering the widespread social distancing that occurred during the COVID-19 pandemic.