Psycho-socio-economic factors and risk of cardiorenal multimorbidity in middle to older-aged adults: prospective findings from the Canadian longitudinal study on aging

Psycho-socio-economic factors (PSEFs) such as income and homeownership may influence the prevalence of cardiorenal multimorbidity (CRM), yet their prospective associations with CRM risk remain unclear. This study aimed to estimate CRM incidence and examine its relationships with multiple PSEFs in a nationally representative Canadian cohort. We analyzed data from 16,557 participants (mean age: 60.4 years; 48.9% men) in the Canadian Longitudinal Study on Aging (CLSA) who were free of CRM at baseline (2010-2015). Incident CRM was defined as the co-occurrence of at least one cardiovascular disease and kidney disease at second follow-up (2018-2021). Survey-weighted multivariable logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs) for PSEFs and CRM risk. Over 3-11 years follow-up, 194 participants (1.2%) developed CRM, corresponding to 8.80 per 1,000 individuals (95% CI: 6.77-11.40). CRM incidence increased with age, was higher in men than women (10.63 vs. 7.35 per 1,000), urban than rural residents (9.69 vs. 3.72 per 1,000), and immigrants than non-immigrants (10.87 vs. 8.49 per 1,000). Greater tangible social support reduced CRM risk (OR = 0.65; 95% CI: 0.43-0.97), while depression (OR = 1.68; 95% CI: 1.07-2.65) and PTSD (OR = 3.14; 95% CI: 1.74-5.67) increased risk. In middle- to older-aged Canadian adults, higher social support appears protective, whereas depression and PTSD increase CRM risk. Although incidence was low, CRM burden rose with age and was higher among men, urban residents and immigrants. These findings highlight the importance of psychosocial well-being and social connectedness in preventing CRM and reducing multimorbidity burden in aging populations.