Multimorbidity and depressive symptoms in older adults and the role of social support: Evidence using Canadian Longitudinal Study on Aging (CLSA) data

BACKGROUND: The rising prevalence of multimorbidity poses challenges to health systems globally. The objectives of this study were to investigate: 1) the association between multimorbidity and depressive symptoms; and 2) whether social support plays a protective role in this association. METHODS: A prospective population-based cohort study was conducted to analyze baseline and 3-year follow-up data of 16,729 community dwelling participants aged 65 and above in the Canadian Longitudinal Study of Aging (CLSA). Multimorbidity was defined as having three or more chronic conditions. The 10-item Center for Epidemiologic Studies Depression scale (CESD-10) was used to measure depressive symptoms. The 19-item Medical Outcomes Study (MOS) Social Support Survey was employed to assess perceived social support. Multivariate logistic regression models were used to examine the association between multimorbidity, social support and depressive symptoms. RESULTS: Multimorbidity was very common among participants with a prevalence of 70.6%. Fifteen percent of participants had depressive symptoms at baseline. Multimorbidity was associated with increased odds of having depressive symptoms at 3-year follow-up (adjusted odds ratio, aOR = 1.51, 95% CI 1.33, 1.71), and developing depressive symptoms by follow-up among those with no depressive symptoms at baseline (aOR = 1.65, 95% CI 1.42, 1.92). Social support was consistently associated with decreased odds of depressive symptoms, regardless of level of multimorbidity. CONCLUSION: Multimorbidity was positively associated with depressive symptoms over time, but social support served as a protective factor. As a modifiable, protective factor, emphasis should be placed in clinical practice to assess social support and refer patients to appropriate services, such as support groups. Similarly, health policy should focus on ensuring that older adults have access to social support opportunities as a way to promote mental health among older adults. Community organizations that offer social activities or support groups play a key role in this respect and should be adequately supported (e.g., with funding).