Plasma FGF-21 and Sclerostin Levels, Glycemia, Adiposity and Insulin Sensitivity in Normoglycemic Black and White Adults
Abstract Increased circulating fibroblast growth factor (FGF)-21 and sclerostin levels have been reported in patients with type 2 diabetes (T2D). We assessed the association of FGF-21 and sclerostin with adiposity, glycemia and glucoregulatory measures in healthy subjects. We studied 20 normoglycemic Black and White offspring of parents with T2D. Assessments included OGTT, insulin sensitivity (Si-clamp), insulin secretion (HOMA-B), and body fat (DXA). Fasting plasma FGF-21 and sclerostin levels were measured with ELISAs. The participants' mean (+SD) age was 50.4 ± 5.97 yr; BMI 32.5 ± 5.86 kg/m2; fasting plasma glucose (FPG) 96.1 ± 5.21 mg/dl, and 2-hr post-load glucose (2hPG) 116 ± 5.45 mg/dl. FGF-21 levels were similar in Blacks vs. Whites (0.36 ± 0.15 ng/ml vs. 0.39 ± 0.25 ng/ml), men vs. women (0.45 ± 0.14 vs. 0.44 ± 0.07ng/ml), correlated positively with body mass index (BMI) (r=0.23, P=0.05) and waist circumference (r=0.27, P=0.04), and inversely with FPG (r= -0.26, P=0.05). Sclerostin levels also were similar in Blacks (33.5 ± 17.1 pmol/l) vs. Whites (34.2 ± 6.41 pmol/l), men vs. women (35.3 ± 9.01 pmol/l vs. 32.3 ± 15.8 pmol/l), and correlated inversely with FPG (r= - 0.11-0.44) but not adiposity measures. The correlation coefficient between Si-clamp values and FGF-21 levels was -0.31 (P=0.09) compared with 0.04 (P=0.89) for sclerostin levels. FGF-21 and sclerostin levels were not correlated with each other or HOMA-B. Among healthy Black and White subjects, plasma FGF-21 and sclerostin showed differential associations with adiposity but concordant association with FPG levels.