Association of loneliness trajectories with chronic obstructive pulmonary disease, a cohort study from China

The association between loneliness and chronic obstructive pulmonary disease (COPD) is unclear. This study aimed to investigate this association and, in particular, analyze the role of loneliness dynamics in COPD. The study population was middle-aged and older (≥45 years) participants without COPD from the China Health and Retirement Longitudinal Study (CHARLS), and the study outcome was the occurrence of COPD during follow-up. Loneliness was assessed by a single-item question score (0-3) addressing loneliness. We collected four loneliness values from 2011-2018 and used group-based trajectory modeling (GBTM) to identify loneliness trajectories. COX proportional risk regression modeling calculated the hazard ratios (HRs) of baseline loneliness and different loneliness trajectories to COPD incidence. In addition, we performed subgroup analyses and sensitivity analyses. A total of 8006 participants were included in this study, with a mean age of 57.4 years and 54.5% female. GBTM analysis identified three trajectories of loneliness: consistently low (76.14%), consistently high (10.60%), and increasing loneliness (13.26%). Participants in the consistently high (HR = 1.66, 95CI%: 1.29-2.12, P < 0.001) and increasing loneliness (HR = 1.65, 95CI%: 1.34-2.04, P < 0.001) groups had a significantly increased risk of COPD compared to the consistently low group. Lonely participants (scores 1-3) at baseline had a 24% increased risk of COPD compared with those not lonely (score 0). Both subgroup and sensitivity analyses confirmed the stability of the results. This study found a significant association between loneliness trajectories and risk of developing COPD, suggesting the importance of psychosocial factors in developing chronic respiratory diseases.