Microbiota and Bone Fragility:Study of the Relation Between Gut Microbiota and Bone Microarchitecture

Gut microbiota regulate metabolism of their human host. Some diseases are associated with variations in gut microbiota diversity and higher fracture risk. Intestinal bacteria synthesize or influence synthesis of factors modulating bone metabolism. The link between gut microbiota and bone was assessed mainly in experimental animal studies. Clinical data, e.g. on the role of gut microbiota in postmenopausal osteoporosis are scarce. The investigators will compare gut microbiota composition in four groups of women aged ≥60 recruited on the basis of bone mineral density (BMD) and personal history of fracture. the participants will have diagnostic exams: clinical tests, bone densitometry (body composition, vertebral fractures), high resolution peripheral QCT (bone strength estimated by microfinite element analysis, micro-FEA), biological sample collection. Gut microbiome profiling will be performed at the INRA MetaGenoPolis laboratory. The investigators will compare gut microbiota diversity according to BMD level and to the fracture status. The investigators will analyze interactions of the gut microbiota diversity with bone status (bone turnover rate, BMD, bone microarchitecture, bone strength estimated by micro-FEA), muscle mass and strength, inflammatory cytokines and micro-RNAs modulating their expression. This study will provide new data concerning the importance of gut microbiota for the fracture risk in older women. It will help to identify the main metabolic pathways underlying the observed associations.