Abstract
BACKGROUND: There is limited evidence on the long-term associations between cardiometabolic multimorbidity (CMM) and multiple domains of functioning, and the potential role of social activity in these associations. We aimed to examine the associations between CMM and joint trajectories of physical disability, depressive symptom, and cognitive function, and whether social activity modifies these trajectories. METHODS: This multicohort study used pooled data of four prospective cohorts of adults from China, the UK, the USA, and Europe. Participants with complete information on cardiometabolic diseases (CMDs, including heart diseases, stroke, and diabetes) and social activity at baseline were included. Physical disability, depressive symptom, and cognitive function were measured one to five times. Longitudinal modelling was used to describe post-baseline trajectories of the three domains, stratified by CMM status and social activity. RESULTS: Among 73,778 participants (age 63.4 ± 9.1 years, 56.0% female), 20.0% had single CMD and 4.3% had CMM at baseline. Participants with single CMD or CMM had persistently worse physical disability, depressive symptom, and cognitive function compared to those without CMD. CMM was associated with faster worsening of physical disability (β(linear change*CMM) = - 0.017 [95% confidence interval = - 0.030 to - 0.004]) and cognitive function (- 0.035 [- 0.050 to - 0.019]), particularly among those with social inactivity. Among 40,883 participants (age 62.9 ± 8.9 years, 55.6% female) in joint trajectory analysis, four trajectories were identified: 'favourable trajectories of physical disability, depressive symptom, and cognitive function' (48.1%); 'worsening cognitive function' (32.6%); 'worsening depressive symptom and cognitive function' (14.6%); and 'rapidly-worsening physical disability and worsening depressive symptom and cognitive function' (4.7%). CMD or CMM were associated with all the three worsening joint trajectories. The highest odds were observed for concurrent worsening across all three functional domains in participants with CMM (odds ratio 3.43 [2.80-4.20]), with more unfavourable trajectories in those with social inactivity (7.26 [5.49-9.59], P for additive interaction < 0.001). CONCLUSIONS: CMM was associated with worse levels, faster progression, and concurrent deterioration in physical disability, depressive symptom, and cognitive function, with the poorest trajectories among those who were socially inactive. This underscores the importance of implementing prevention strategies that integrate physical, psychological, cognitive, and social activities.