Comparing loneliness, social inactivity, and social isolation - associations with health-related quality of life and mortality among home-dwelling older adults

Introduction: Loneliness, social inactivity, and social isolation are intertwined concepts. When assessed separately, they indicate poor well-being, adverse health effects, and increased mortality. Studies exploring overlapping and comparing the prognosis of these concepts are scarce. We investigated (1) overlapping of concepts of loneliness, social inactivity, and social isolation, (2) characteristics of groups: group 0 (not lonely, socially inactive, or socially isolated), group 1 (lonely), group 2 (not lonely but socially inactive and/or socially isolated), and (3) the health-related quality of life (HRQoL), psychological well-being (PWB), and 3.6-year mortality of these groups. Methods: The home-dwelling older adults (n = 989; 75 y+) of the Helsinki Aging Study in 2019–2022 completing all required questionnaires were assessed. Group 0 included 494, group 1 included 280, and group 2 included 215 participants. Variables studied were demographics, diagnoses, mobility, physical functioning (Barthel index), and cognition (Mini-Mental State Examination). Outcomes were HRQoL (15D) and PWB. Mortality was retrieved from central registers. Results: Half of the sample was lonely, socially inactive, or socially isolated, but only 2% were simultaneously lonely, socially inactive, and socially isolated. Of lonely participants, 38% were also socially inactive and/or socially isolated. The lonely participants were significantly more often widowed or lived alone and had the lowest HRQoL and poorest PWB compared with the other groups. After adjustments (age, sex, Charlson Comorbidity Index), mortality did not statistically differ between the groups. Conclusion: Loneliness is an independent determinant of poor HRQoL and PWB, and it should be considered separately from social inactivity and social isolation.