High FGF-23 Levels Linked to Lower Adiposity in Dialysis Patients

Fibroblast growth factor 23 (FGF-23) is inversely associated with adiposity in patients on hemodialysis (HD), and this association may be mediated, at least in part, by leptin, a new study suggests.

According to investigators, a decrease in adipose tissue may be a mechanism by which higher FGF-23 levels may contribute to greater mortality among dialysis patients. They postulate that the effect of FGF-23 levels on adipose tissue may have a role in the obesity paradox observed in patients with end-stage renal disease (ESRD).
In a study of 611 prevalent hemodialysis (HD) patients, Janet M. Chiang, MD, of the University of California, San Francisco, and colleagues found that FGF-23 was inversely associated with body mass index (BMI), waist circumference, and percent body fat. Each 50% increase in FGF-23 was associated with a 0.24 kg/m2 decrease in BMI, 0.44 cm decrease in waist circumference, and 0.58 % decrease in percent body fat, Dr Chiang’s team reported in the Journal of Renal Nutrition (2018;28:278-282).
Adding leptin to body composition models attenuated the associations between FGF-23 and measures of adiposity, but FGF-23 remained significantly associated with percent body fat, with each 50% increase in FGF-23 associated with a 0.17% decrease in percent body fat.
“In conclusion, we found that there is an inverse relationship between FGF-23 and adiposity that is different from what is seen in individuals with normal renal function,” the authors wrote. “This paradoxical association could be due to off-target signaling of FGF23 in the adipose tissue leading to increased lipolysis of fat. This observation could add to our understanding of factors that lead to the obesity paradox in ESRD.”
They noted that multiple “endocrine factors, including FGF-23 and leptin, communicate between bone, kidney, and adipose tissue to balance mineral and energy homeostasis.”

Reference:
Chiang JM, Kaysen GA, Schafer AL, et al. Fibroblast growth factor 23 is associated with adiposity in patients receiving hemodialysis: Possible cross talk between bone and adipose tissue. J Ren Nutr. 2018;28:278-282.