Osteoporosis is a metabolic disorder of bone, characterized by increased bone resorption. Serum collagen type 1 cross-linked C-telopeptide (CTX) is increased during bone resorption. In our preliminary metabolomic analysis, which aimed to identify the metabolic consequences of reduced bone turnover in a cohort of adults with high bone mineral density, we identified a positive relationship between serum CTX and NMR-assessed serum citrate levels (unpublished data). Citrate is a component of bone mineral with a potential structural function (Costello et al 2013). We aim to repeat our cross-sectional analysis of the association between serum CTX and serum citrate in both the ALSPAC mothers and adolescents population to determine if this association replicates, firstly in a general population cohort of a similar age, and secondly in a younger population, which would suggest that serum citrate is a novel marker of bone resorption.