World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (WCO-IOF-ESCEO 2023)

Abstract

Objective: Ageing is associated with unbalanced gut microbiota (GM). While previous research has suggested that GM dysbiosis contributes to adverse health outcomes such as depression andMorbus Parkinson, more research is needed to determine the role of the gut-muscle axis in humans. Therefore, this systematic review aimed to clarify the associations between sarcopenia and its defining parameters (muscle mass, muscle strength, physical performance) and GM in older adults. Methods: A systematic search was conducted according to the PRISMA guidelines in PubMed, Embase, Web of Science and Cochrane Library after registration on PROSPERO (CRD42021259597). Studies reporting on the construct sarcopenia or at least one defining parameter and GM were screened from inception until 19 July 2022. Observational (cross-sectional, cohort, case-control) studies with subjects ≥ 50 years were included. Results: 25 studies with 5400 subjects (52% women) were included (18 cross-sectional, 4 case-controls, 3 cohort). The majority of studies comprised community-dwelling (n = 21) and Caucasian (n = 15) older persons. 12 studies adjusted for putative confounders. 8 studies had the construct sarcopenia (by varying definitions) as one of the outcomes, with prevalence ranging from 11 to 51%. In 9 studies at least 1 α-(within sample) GM diversity index and in 11 studies at least 1 β-(between sample) GM dissimilarity index was different in older persons with preserved vs. low muscle function. Four studies reported differences in Firmicutes/Bacteroides ratio, which was increased in normal vs. low muscle mass groups in 3 of these. Multiple studies reported associations between bacterial taxa at multiple levels (phylum, family, genus and species) and muscle mass (n = 10), muscle strength (n = 7) and physical performance (n = 3). The construct sarcopenia was associated with higher abundance of specific bacterial taxa (5 out of 8 studies). All mentioned results were significant (p ≤ 0.05). Conclusion: This review suggests significant associations between GM and sarcopenia or at least one defining parameter. However, results were highly heterogenous, and no conclusions about causality could be made. Therefore, additional longitudinal research with larger sample sizes is needed to unravel the gut-muscle axis in older persons with sarcopenia.