Background: Aging is accompanied by chronic low-grade inflammation (inflammaging), which is a risk factor for low handgrip strength (HGS) and activities of daily living (ADL) disability.
Aims: To explore the association between C-reactive protein (CRP) and ADL disability in Chinese elderly individuals and to further evaluate the mediating role of HGS in this association.
Methods: We used data from the China Health and Retirement Longitudinal Study (CHARLS) that were collected in 2015. A total of 3601 elderly individuals aged ≥ 60 years were included. Baron and Kenny's causal steps method was used to explore the possible mediating role of HGS in the associations between CRP and ADL disability. Karlson-Holm-Breen method was further applied to decompose total effect into direct effect and indirect effect via HGS. Subgroup analysis was conducted by sex and age.
Results: A high level of CRP (≥ 3 mg/L) was significantly associated with ADL disability after adjustment for covariates (OR = 1.50, 95% CI = 1.17-1.94). After introducing HGS into the model, the risk estimate was reduced but still significant (OR = 1.40, 95% CI = 1.08-1.81). The proportional mediation through HGS was 14.71%. Similar results were observed in both sexes and in participants aged < 70 years.
Conclusion: CRP was positively associated with the risk of ADL disability in Chinese elderly individuals, and this association was mediated by HGS. Improving muscle strength in combination with anti-inflammatory treatment may have a beneficial effect to maintain ADL ability. Further randomized controlled trials on this topic are necessary.
Keywords: Activities of daily living; Disability; Elderly; Handgrip strength; Inflammation; Mediating effect.
© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.