Gender Specific Association between Serum Fibroblast Growth Factor 23/α-Klotho and Coronary Artery and Aortic Valve Calcification

Fibroblast growth factor 23 (FGF23) and α-Klotho have been recently identified to play a crucial role in calcium/phosphate metabolism. We herein investigated the possible relation between serum FGF23/α-Klotho levels and coronary artery calcification (CAC) and aortic valve calcification (AVC).Among subjects with diagnosed or suspected coronary artery disease (CAD), CAC and AVC were estimated via the Agatston score of 320-detector computed tomography images, and serum FGF23 and α-Klotho levels were measured.In total, 157 subjects were enrolled (75 women and 82 men). We performed logistic regression using CAC as a dependent variable; the highest FGF23 tertile (＞ 52.5 pg/mL) was significantly positively associated with CAC with an odds ratio of 6.61 versus the lowest FGF23 tertile (＜ 35.3 pg/mL) in women after the adjustment for potential confounding variables including age, renal function, hypertension, statin use, diuretic use, and calcium/phosphate metabolism related factors. In addition, the highest α-Klotho tertile (＞ 561 pg/mL) was significantly associated with AVC with an odds ratio of 6.31 versus the lowest α-Klotho tertile (＜ 306 pg/mL) in men after adjusting for the same variables. On the other hand, the association between FGF23 and CAC/AVC in men or that between α-Klotho and CAC/AVC in women was nonsignificant.Among subjects with diagnosed or suspected CAD, serum FGF23 was positively associated with CAC in women and serum α-Klotho was positively associated with AVC in men independent of the confounding variables, including the renal function and calcium/phosphate metabolism-related factors.