Brain-Derived Neurotrophic Factor, Sarcopenia and Digital Gait Characteristics in Older Adults: Insights Into the...

Brain-derived neurotrophic factor (BDNF) is a core biomarker involved in the brain-muscle axis. This study aimed to investigate the associations of plasma BDNF with sarcopenia and multidimensional gait characteristics in older adults.

We enrolled 646 adults aged 60 years and older (mean age = 70.46 years; 56.97% females), among whom 65 (10.06%) were diagnosed with sarcopenia according to the Asian Working Group for Sarcopenia 2019. All participants underwent body composition analysis, comprehensive physical function assessments (handgrip strength, 6-m walk and five-time sit-to-stand test), and wearable sensor-based gait evaluation (including 14 parameters). Plasma levels of BDNF, along with multiple inflammatory and oxidative stress markers, were quantitatively measured. Multivariable regressions were conducted to examine the association of BDNF with sarcopenia and gait parameters, with adjustments for demographic characteristics, lifestyle factors, activities of daily living, cognitive function, depression and comorbidities.

Plasma BDNF levels were significantly lower in older adults with sarcopenia compared to those without [1.82 (0.62, 4.95) μg/L versus 4.12 (0.81, 11.46) μg/L, p = 0.003]. BDNF was significantly correlated with appendicular skeletal muscle mass index (r = 0.11, p = 0.018), handgrip strength (r = 0.27, p < 0.001), gait speed (r = 0.32, p < 0.001) and sit-to-stand time (r = -0.34, p < 0.001). After full adjustment for covariates, the odds ratio (OR) for sarcopenia of ln-BDNF was 0.71 (95% CI: 0.63-0.81, p = 0.012). Ln-BDNF was negatively associated with swing time (β = -7.833, p = 0.011), step time (β = -12.769, p = 0.016), and stride time (β = -0.026, p = 0.012); and positively associated with thigh acceleration (β = 0.066, p = 0.001), thigh swing work (β = 0.039, p < 0.001), ground reaction force (β = 0.083, p < 0.001), foot landing control force (β = 0.224, p < 0.001), toe-off angle (β = 2.061, p < 0.001), step frequency (β = 1.615, p < 0.001) and stride length (β = 0.013, p < 0.001). Interleukin-6, interleukin-1β, superoxide dismutase and glutathione reductase were concurrently correlated with BDNF levels, sarcopenia status and gait parameters. Mediation analysis demonstrated that interleukin-1β mediated 14.65% of the relationship between BDNF and sarcopenia.

Higher BDNF levels are associated with a lower prevalence of sarcopenia and superior kinetic and spatiotemporal gait performance in older adults. Future experimental studies are needed to explore the potential mechanism by which BDNF regulates sarcopenia via neuroinflammation.