Trajectories of loneliness, social isolation, and depressive symptoms before and after onset of pain in middle-aged and older adults.

Background: Chronic pain is associated with poor psychosocial wellbeing; how loneliness, social isolation, and depressive symptoms evolve leading up to and following pain onset is unclear. We examined trajectories of these outcomes before and after pain onset. Methods: We analysed data from participants aged ≥50 years from the English Longitudinal Study of Ageing (ELSA). Data collection began in 2002 (wave 1) and was repeated biennially until 2019 (wave 9); wave 10 took place in 2021/23. Participants who had data from at least 2 waves were included. Participants reporting pain between 2002 and 2023 ('pain group') were matched with an equivalent number without pain ('no-pain group'; N = 7336 total). Psychosocial outcomes were also assessed at each wave: Loneliness using the three-item subscale from the revised UCLA loneliness scale; social isolation using a score ranging from 0 to 5, with a higher score indicating more severe social isolation; and depression using the 8-item Center for Epidemiologic Studies Depression Scale. Piecewise linear mixed models were used to produce trajectories of loneliness, social isolation, and depressive symptom scores before and after pain onset and during the comparable time period in the no-pain group. Subgroup analyses examined how results differed by age, sex, education, and wealth. Findings: Loneliness and depressive symptoms were more severe for the pain group than the no-pain group before pain onset (e.g., difference [pain-no pain] eight years before pain onset = 0.19 points, 95% confidence interval = 0.11-0.28 for loneliness; difference = 0.14, 0.06-0.22 for depressive symptoms). For loneliness, this difference increased consistently during the study period (e.g., difference = 0.33, 0.26-0.40 eight years after pain onset). For depressive symptoms, the difference increased sharply to 0.58 (0.52-0.65) at pain onset and remained stable thereafter. Differences in depressive symptoms were most pronounced in less educated and less wealthy participants. There were negligible differences between pain and no-pain groups for social isolation. Interpretation: Loneliness and depressive symptoms progressively increased in severity years before pain onset. A holistic approach to pain is needed, incorporating early psychosocial interventions and targeted strategies for vulnerable populations. Funding: Nuffield Foundation Oliver Bird Fund, Versus Arthritis.