Sclerostin Associated with Vertebral Bone Marrow Fat in Older Men but Not Women

Marrow fat (MF) and bone density (BMD) are negatively correlated.Proposed mechanisms include 1) a shift in stem cell lineage allocation from osteoblasts towards adipocytes, and 2) an increase in osteoclast-promoting cytokines with greater MF.• Sclerostin is expressed by osteocytes and reduces bone formation by inhibiting the Wnt/B-catenin pathway.• Circulating sclerostin is also associated with higher BMD.However, the relationship between circulating sclerostin and MF is not known.• Circulating sclerostin increases with weight loss but little is known about relationships with the separate compartments of fat and lean mass. PRIMARY OBJECTIVETo characterize the relationships between circulating sclerostin and MF, QCT measurements of hip and spine, and body composition parameters, we used data from the Iceland AGES-Reykjavik cohort of older adults. Methods