Abstract T P134: Fibroblast Growth Factor 23 and Risk of Incident Stroke in the Regards Study
Objective: Fibroblast growth factor 23 (FGF23) is a hormone that regulates phosphorus and vitamin D metabolism. Elevated levels of FGF23 are strongly associated with heart disease and death, particularly in persons with chronic kidney disease (CKD). Whether FGF23 is also associated with stroke risk is unclear.
Methods: Using a case cohort design we examined the association of plasma FGF23 with incident stroke in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, a cohort of black and white participants from across the United States. Baseline assessment occurred between 2003 and 2007. All physician-adjudicated stroke cases through July 1, 2011 were included in the analysis. Using stored samples, FGF23 was measured on 610 stroke cases and 939 cohort members, all of whom were stroke-free at baseline. The cohort random sample was selected to ensure approximately equal numbers of black and white participants and an equal distribution across ages. We used Cox proportional hazards models weighted back to the original 30,239 participants sampled by the REGARDS study to account for oversampling of stroke cases.
Results: Participants were followed for a mean of 4.4 years. Higher FGF23 was associated with older age, female sex, lower socioeconomic status, diabetes, and CKD (estimated glomerular filtration rate < 60 ml/min or urinary albumin to creatinine ratio ≥ 30 mg/g). After adjustment for age, race, sex, education, diabetes, hypertension, smoking, atrial fibrillation, heart disease, physical activity, calcium, phosphorus, and serum vitamin D, higher FGF23 levels were associated with greater risk of incident stroke (HR per doubling of FGF23=1.19; 95%CI=1.03, 1.37). After further adjustment for CKD, this association was attenuated and no longer statistically significant (HR per doubling of FGF23=1.06, 95%CI 0.90, 1.25).
Discussion: Higher FGF23 is associated with greater risk of stroke, but this association is largely explained by CKD.
Author Disclosures: B. Panwar: None. N. Jenny: None. V. Howard: None. V. Wadley: None. P. Muntner: None. S. Judd: None. O. Gutierrez: None.
- © 2014 by American Heart Association, Inc.