Associations of serum fibroblast growth factor 23 levels with obesity and visceral fat accumulation

Background & aims: Recent findings raise the possibility that fibroblast growth factor (FGF) 23 may be related with fat contents and distribution. The present study aimed to elucidate the associations of serum FGF23 levels with the fat contents and distribution. Methods: A total of 1599 normoglycemic individuals with preserved kidney function were enrolled. Serum levels of intact FGF23 were detected using a sandwich enzyme-linked immunosorbent assay. Overweight/obesity was defined by a body mass index of >= 25.0 kg/m(2). Visceral fat area (VFA) was assessed by magnetic resonance imaging, and abdominal obesity was defined as VFA >= 80 cm(2). Results: Among the study population of 597 men, 411 premenopausal women, and 591 postmenopausal women, serum FGF23 levels were significantly increased in participants with overweight/obesity and abdominal obesity, respectively (both P < 0.001). Each one-unit increase in VFA was associated with a 0.028-pg/mL increase in serum FGF23 levels in men (P = 0.001) and a 0.051-pg/mL increase in serum FGF23 levels in postmenopausal women (P < 0.001). Whether in the presence of overweight/obesity or not, the presence of abdominal obesity was independently associated with the increase in serum FGF23 levels in men and postmenopausal women (all P < 0.05). Conclusions: Serum FGF23 levels are elevated in obese individuals, especially those with abdominal obesity. The independent associations between the presence of abdominal obesity and the increase in serum FGF23 levels in specific groups suggest that serum FGF23 levels may indicate the risk of metabolic and cardiovascular disease in men and postmenopausal women. (C) 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.