The longitudinal relation between loneliness and perceived stress: A structural equation modelling analysis of 10,159...

Prolonged loneliness and severe stress are increasingly recognised as public health concerns and considered risk factors for mental disorders, somatic illnesses and mortality. Loneliness and perceived stress also often co-occur; however, their longitudinal relation remains unclear. To the best of our knowledge, this is the first study aiming to investigate the longitudinal relation between loneliness and perceived stress independently of cross-sectional associations and time effects.

Designed as a population-based cohort study with repeated measurements, the present study included individuals aged 16-80 years at baseline who participated in the Danish National Health Survey ('How are you?') in 2013 and 2017 (N = 10,159; response rate = 50%). Structural equation modelling was used to examine associations between loneliness and perceived stress in the total sample and across age groups (i.e., 16-29, 30-64 and 65-80 years).

The models indicated bidirectional relations between loneliness and perceived stress. The standardized cross-lagged path from loneliness to perceived stress (β: 0.12, 95% confidence interval (CI) (0.08, 0.16), p < 0.001) and from perceived stress to loneliness (β: 0.12, 95% CI (0.07, 0.16), p < 0.001) both corresponded to small effect sizes in the total sample. Additionally, the results indicated strong cross-sectional associations, especially among adolescents and young adults (16-29 years), and high temporal stability, especially among the elderly (65-80 years).

Loneliness and perceived stress mutually predict each other over time. The finding of both substantial bidirectional and cross-sectional associations demonstrates an interdependence between loneliness and perceived stress that may be relevant to consider in future interventions.