FGF23: a novel predictor of fracture risk in elderly men

A normal mineral metabolism is mandatory for skeletal development and preservation of bone integrity. Fibroblast growth factor-23 (FGF23) is a bone-derived circulating factor that decreases serum concentrations of inorganic phosphorous (Pi) and 1,25-dihydroxy vitamin D3 (1,25(OH)2D3). Increased FGF23 expression is a direct or indirect culprit in several skeletal disorders; however the relationship between FGF23 and fracture risk remains undetermined. The authors of a recent study [1] evaluated the prospective relationship between serum intact FGF23 and fracture risk, employing the Swedish part of the population-based, Osteoporotic Fractures in Men Study (MrOS) (n=2868; mean age 75.4 ± 3.2; median follow-up period 3.35 years).

The incidence of at least one validated fracture after baseline was 20.4 per 1000-person-years. FGF23 was directly related to the overall fracture risk and vertebral fracture risk. There was a nonlinear relationship between FGF23 and fracture risk, with the strongest relationship at FGF23 levels above 55.7 pg/mL. FGF23 levels above 55.7 pg/mL were also associated with an increased risk for hip and non-vertebral fractures. These relationships remained essentially unaltered after adjustment for BMI, BMD, glomerular filtration rate, 25(OH)D3, PTH and other fracture risk factors.

In conclusion, FGF23 is a novel predictor of fracture risk in elderly men.

1. Mirza MAI et al. J Bone Miner Res. 2010;DOI 10.1002/jbmr.263