Association between gut microbiota and sarcopenia in older adults: a cross-sectional analysis from the second wave of...

Investigating gut microbiota has emerged as a novel approach to exploring the gut-muscle axis and its link to age-related conditions like sarcopenia. While studies suggest gut dysbiosis may promote inflammation and muscle loss, findings vary by region and ethnicity. This study examined the association between gut microbiota and primary sarcopenia in an older adult population in Iran.

This cross-sectional study analyzed 293 community-dwelling participants (aged ≥ 60 years) from the second wave of the Birjand Longitudinal Aging Study in Iran. Fecal samples were collected, and gut microbiota composition was assessed for 12 bacterial genera using quantitative Real-time PCR with genus-specific primers. Sarcopenia was defined according to the 2019 Asian Working Group for Sarcopenia (AWGS) criteria, based on anthropometric measurements, body composition (via bioelectric impedance analysis), handgrip strength, and walking speed. Associations between the abundance of each bacterial genus and sarcopenia, as well as its individual components, were assessed.

Out of 293 participants, 38.2% (n = 112) were diagnosed with sarcopenia. Participants with sarcopenia were older than those without sarcopenia (mean age 72.99 ± 6.13 vs. 70.20 ± 5.24 years) and had a different sex distribution (55.4% vs. 60.2% women in the sarcopenic and non-sarcopenic groups, respectively). Higher Akkermansia abundance was associated with greater odds of sarcopenia and was negatively correlated with handgrip strength, skeletal muscle index (SMI), and gait speed (p < 0.05). Akkermansia was also associated with low SMI, and low gait speed; each unit increase in Akkermansia was associated with 9% higher odds of low SMI and 8% higher odds of low gait speed. Both Akkermansia and Lactobacillus increased the odds of sarcopenia by 7% and 8%, respectively, whereas Roseburia showed an inverse association with sarcopenia and each unit increase in Roseburia decreased the odds of sarcopenia by 11.5%. Roseburia was also positively correlated with gait speed (p < 0.05).

This study demonstrates that specific gut microbial profiles are significantly associated with sarcopenia. Akkermansia and Lactobacillus were associated with sarcopenia, although greater Roseburia levels were beneficial. These microbial signatures are associated with sarcopenia and warrant further longitudinal investigation.