Associations of digital exclusion with joint trajectories of depression and self-rated health: evidence from two prospective longitudinal studies

The aim of this study is to explore the joint developmental trajectories of depression and self-rated health in middle-aged and older adults from China and the United Kingdom, and to analyse the relationship between digital exclusion and each potential trajectory. This study utilised five waves of national data from the China Health and Retirement Longitudinal Study (CHARLS 2011–2020) involving 8471 participants aged ≥ 45 years and five waves of data from the English Longitudinal Study of Ageing (ELSA 2012–2020) involving 2682 participants aged ≥ 45 years. Using parallel process latent class growth analyses (PP-LCGA) and multifactorial regression analyses, we identified joint long-term developmental trajectories of depression and self-rated health in participants from two countries and assessed the association between digital exclusion and these trajectories. CHARLS and ELSA identified four and three joint developmental trajectories, respectively. CHARLS included a medium starting point stable group (44.7%), a low starting point health improvement group (16.4%), a high starting point growth group (30.6%), and an ultra-high starting point growth group (8.2%). With the ultra-high starting point growth group as the reference category, participants who experienced digital exclusion had higher depressive symptom scores and poorer self-rated health than internet users, and were more likely to belong to the ultra-high starting point growth group. The ELSA comprised the high starting point growth group (11.4%), the medium starting point growth group (38.9%), and the low starting point stable group (49.7%). The results of the ELSA regression analysis are similar to those of CHARLS: using the low starting point stable group as the reference category, participants who experienced digital exclusion were more likely to be classified into the high starting point growth group and the medium starting point growth group. Our research suggests that depression and self-rated health show distinct joint developmental trajectories, some of which worsen with age, and that digital exclusion is associated with higher depressive symptoms and poorer self-rated health. These observational findings suggest that digital inclusion may be a promising component of strategies to support mental health and self-rated health in middle-aged and older adults, although causal effects cannot be inferred.