Age-related patterns of loneliness during early cancer survivorship, risk factors, and associated health outcomes.

BACKGROUND: Loneliness can have profound health consequences for cancer patients, yet age-related patterns of loneliness remain inconsistent and mainly cross-sectional. We describe loneliness in young (<40 years), middle-aged (40-65 years), and older (≥65 years) patients over time during early cancer survivorship, identify biopsychosocial risk factors for loneliness, and examine its impact on health outcomes across age groups. METHODS: This multicenter prospective longitudinal study included cancer patients within two months of diagnosis and at 6-, 12-, and 18-month follow-ups. Loneliness was measured using the UCLA loneliness scale. Generalized-linear-mixed-models examined changes over time. Mixed-effects regression models identified risk factors for loneliness and examined the predictive value of loneliness on physical and mental health outcomes over time. RESULTS: In total, 994 patients (53% men, 60.5 years) were included in this analysis. Older patients reported lowest and most stable loneliness over time (15-20%), whereas middle-aged (19-31%) and young (25-38%) patients reported higher loneliness values, particularly shortly after diagnosis. Risk factors for being lonely included lower social support, absence of a partner, lower socioeconomic status, advanced disease, and greater comorbidity burden (all p < 0.05). Higher loneliness at diagnosis predicted mental disorders and psychosocial care needs at follow-ups, in addition to distinct age-specific relationships of reduced physical and mental QoL for middle-aged, and non-adherence for older patients (all p < 0.05). CONCLUSION: Loneliness is common during early cancer survivorship, particularly among young and middle-aged patients shortly after cancer diagnosis. Age-related mechanisms, vulnerabilities and consequences of loneliness may inform clinical communication, e.g. about non-adherence or recommendation of tailored psychosocial support. TRIAL REGISTRATION: This study was registered in the International Clinical Trials Registry (NCT04620564, https://clinicaltrials.gov/).