TY - JOUR T1 - Fibroblast Growth Factor 23, Mineral Metabolism, and Adiposity in Normal Kidney Function. JF - J Clin Endocrinol Metab Y1 - 2017 A1 - Zaheer, Sarah A1 - de Boer, Ian H A1 - Allison, Matthew A1 - Brown, Jenifer M A1 - Psaty, Bruce M A1 - Robinson-Cohen, Cassianne A1 - Michos, Erin D A1 - Ix, Joachim H A1 - Kestenbaum, Bryan A1 - Siscovick, David A1 - Vaidya, Anand KW - Adiposity KW - Aged KW - Aged, 80 and over KW - Cross-Sectional Studies KW - Female KW - Fibroblast Growth Factors KW - Glomerular Filtration Rate KW - Humans KW - Kidney KW - Male KW - Middle Aged KW - Minerals KW - Renal Insufficiency, Chronic KW - Risk Factors AB -

Context: Obesity is associated with poor bone mineralization and quality. Fibroblast growth factor 23 (FGF23) plays an important role in skeletal physiology.

Objective: To test hypothesis that greater adiposity results in higher FGF23 levels among individuals with normal estimated glomerular filtration rate (eGFR).

Design, Setting, Participants: Cross-sectional analyses among participants with eGFR ≥60 mL/min/1.73m2. We assessed the association between crude [body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR); n = 5610] and refined (abdominal adipose tissue area by computed tomography; n = 1313) measures of adiposity and FGF23 using multivariable linear regression.

Main Outcome Measure: Serum FGF23.

Results: FGF23 was higher across BMI categories (BMI <25: 37.7; BMI 25 to 29.99: 38.7; BMI 30 to 39.99: 39.8; BMI ≥40: 40.9 pg/mL, unadjusted P trend < 0.0001). The association between BMI and FGF23 was independent of known confounders of FGF23 (adjusted β = +7.2% higher FGF23 per 10 kg/m2; P < 0.0001). Similar results were observed using WC and WHR. Abdominal adipose tissue area was also independently associated with higher FGF23 (P < 0.01). Notably, the positive associations between FGF23 and adiposity were observed despite the fact that eGFR did not decline and serum phosphate levels did not increase with adiposity.

Conclusion: In a large cohort with normal kidney function, adiposity was associated with higher FGF23 levels independent of known confounders, including eGFR and phosphate. Further studies are needed to evaluate the causes of higher FGF23 in settings of greater adiposity and the potential impact on skeletal health.

VL - 102 IS - 4 ER -