Relationships between physical frailty, depressive symptoms, and cognitive ability among community-dwelling older adults in India

Abstract

Background: With a rapidly aging population, physical frailty has become a significant public health concern globally. While the association between frailty, depression, and cognitive decline has been widely studied in developed countries, there is limited evidence from low- and middle-income countries, including India. Additionally, little is known about the sex-specific associations between frailty, and mental and cognitive health outcomes. We examined the associations of physical frailty with depressive symptoms and cognitive functioning among older Indian men and women, while also exploring how the frailty-cognition link differs between those with and without depression.

Methods: We used data from the Longitudinal Aging Study in India, conducted between 2017 and 2019. The analytic sample consisted of 14,652 males and 15,899 females aged ≥ 60 years. Frailty was assessed using a modified version of Fried's frailty phenotype, depressive symptoms were evaluated using the Composite International Diagnostic Interview- Short Form, and cognitive ability was measured through memory, orientation, arithmetic, executive function, and object naming tasks. Univariate and multivariable linear regression models were used to examine the associations between frailty, depressive symptoms, and cognitive ability in older men and women, as well as frailty-cognition association by depressive status.

Results: The prevalence of frailty was higher in older women than that in older men (32.2% vs. 27.4%). The mean depressive symptom score was higher (0.8 vs 1.0), and the mean cognitive score was lower (26.4 vs 22.1) among older women than men. Physical frailty was associated with higher levels of depressive symptoms (β = 0.51; 95% CI: 0.39, 0.64), and poor cognitive performance (β = -1.06; 95% CI: -1.37, -0.75). Non-frail older men had lower depressive symptoms than frail older men (β = -0.48; 95% CI: -0.66, -0.31), however, the association was not significant among older women. Furthermore, frail older women performed worse on cognitive tests than did frail older men (β = -2.14; 95% CI: -2.40, -1.87). In addition, non-frail older women had poorer cognitive performance than frail older men (β = -0.77; 95% CI: -1.22, -0.32). Conversely, stratification by depressive status showed that frailty was associated with worse cognitive ability, with no difference between individuals with and without depression.

Conclusions: We found that frail older individuals, particularly women, have significant mental and cognitive deficits compared with their non-frail counterparts. Our findings have major implications in both community and clinical settings. Appropriate policies and programs should be implemented to reinforce the strength of pre-frail and frail older adults and maintain improved mental health and cognition in older adults.

Keywords: Cognitive ability; Depressive symptoms; India; Older adults; Physical frailty.

Fig. 1

Directed Acyclic Graph (DAG) of the hypothesized relationships between physical frailty, depressive symptoms, and cognitive ability among older Indian adults (LASI, 2017–2019) Notes: Solid arrows represent direct hypothesized causal paths, while dotted/dashed arrows indicate stratification/interaction effects. Covariates are modeled to influence physical frailty, depressive symptoms and/or cognitive ability. The model incorporates interaction terms of frailty × gender, and frailty × depression to examine differential associations across subgroups