Abstract P281: Association of Circulating Fibroblast Growth Factor-23 with Adiposity and Lipoprotein Concentrations in African Ancestry Men
Fibroblast growth factor-23 (FGF23) is a bone-derived regulator of vitamin D and phosphate metabolism that has recently been implicated as a potential novel factor in cardiovascular disease. A single study in older Caucasian individuals found an association between FGF23 and overall adiposity and dyslipidemia. However, there has been no research on FGF23 and measures of ectopic fat depots, or any studies in populations of African ancestry, which are disproportionately affected by cardiovascular disease. Therefore, we tested the association of circulating FGF23 with measures of adiposity and lipoprotein concentrations in 490 African ancestry men aged 65 years and older (Mean: 71.5; range: 65-92). Circulating FGF23 and lipoproteins were measured in fasting serum samples. Percent body fat was measured by dual-energy x-ray absorptiometry. Subcutaneous adipose tissue (SAT) and intermuscular adipose tissue (IMAT) were measured at the calf using quantitative computed tomography. Relationships between FGF23 and cardiometabolic risk factors were evaluated with Pearson partial correlation coefficients and linear regression. Mean FGF23 was 36.2pg/mL (range: 1.69-103.2pg/mL). After adjustment for age, diabetes, hypertension, alcohol intake and smoking, FGF23 was positively correlated with general adiposity as assessed by BMI, weight, waist circumference and percent body fat (coefficient range 0.10-0.15, all P<0.05). FGF23 was also negatively correlated with HDL-c independent of general adiposity (r -0.10, P<0.05). Additionally, 1 standard deviation greater FGF23 was associated with 8.2% greater IMAT, independent of age, BMI, diabetes, hypertension, alcohol intake and smoking (P=0.04). FGF23 remained significantly associated with adiposity traits, but not HDL-C, after adjustment for kidney function assessed by eGFR. No significant associations were seen with LDL-c, triglycerides or SAT. Our findings suggest that in older African ancestry men, higher FGF23 concentrations are associated with greater adiposity and lower HDL-c levels, and may play a previously unrecognized role in ectopic skeletal muscle fat distribution.
- © 2013 by American Heart Association, Inc.