Functional Impact of Pain and Its Association With Sarcopenia in the Elderly: The Birjand Longitudinal Aging Study...

Sarcopenia, characterized by the loss of muscle mass and strength, is a prevalent geriatric condition associated with increased morbidity and healthcare burden. Understanding its multifactorial etiology is essential for effective prevention and management.

This study aimed to investigate the association between chronic pain and sarcopenia and to identify demographic, nutritional, and functional factors associated with sarcopenia in a cohort of older Iranian adults.

A cross-sectional analysis was conducted using baseline data from 1344 participants aged ≥ 60 years from the Birjand Longitudinal Aging Study (BLAS). Participants were classified into four groups based on the European Working Group on Sarcopenia in Older People-version 2 (EWGSOP2) criteria: robust, probable sarcopenia, sarcopenia, and severe sarcopenia. Pain was assessed using the brief pain inventory (BPI), with pain severity score and pain interference score (BPI9) as primary variables. Multivariable and multinomial logistic regression models adjusted for socioeconomic, nutritional, and functional covariates were used to assess associations.

In logistic regression analyses, pain interference score was significantly associated with higher odds of sarcopenia across all models, including the fully adjusted model (OR = 1.24, 95% CI: 1.11-1.39, p < 0.001), whereas pain severity score was not associated with higher odds of sarcopenia in binary models (p > 0.05). In multinomial logistic regression, pain interference score demonstrated a graded association with sarcopenia severity, with the strongest effect observed for severe sarcopenia (final model RRR = 1.32, 95% CI: 1.15-1.52, p < 0.001) and a moderate effect for probable sarcopenia (RRR = 1.13, 95% CI: 1.05-1.22, p = 0.003). The association between pain severity and sarcopenia severity was not significant in final adjusted model. Sensitivity analyses using an alternative sarcopenia definition confirmed these findings.

Pain interference, rather than pain severity, is significantly associated with sarcopenia. These findings highlight the importance of addressing pain-related functional limitations in efforts to prevent and manage sarcopenia, particularly in aging populations within low- and middle-income countries.