Study of FGF21 Levels in Transgender People and its Association with Metabolic Parameters

BACKGROUND: Fibroblast growth factor (FGF21) is a metabolic regulator whose role in humans is unidentified. FGF21 has generated a lot of potential of becoming a therapeutic agent for the management of type 2 diabetes mellitus and dyslipidaemia. The role of FGF21 in gender dysphoria individuals has not been studied. OBJECTIVE: Primary objective was to assess FGF21 levels in transgender individuals and compare with controls and secondary objective was to compare FGF21 levels with lipid and glucose parameters in transgender people. RESULTS: Twenty-three transfemales and 21 transmales were included in the study and compared with 44 controls. Height and fasting blood glucose of transfemales was statistically greater than transmales, with no other differences in baseline characteristics. Although FGF21 levels were numerically greater in transfemales (183.50 ± 97.39), it was not statistically significant. FGF21 levels did not vary statistically when compared to controls although it was numerically higher. Univariate analysis was done in transgender patients and FGF21 levels were positively correlated with serum total cholesterol and serum LDL cholesterol in transfemales but not in transmales. Multivariate analysis was also done taking 50(th) centile and 75(th) centile of FGF21 levels of controls and was found that only serum total cholesterol and serum LDL positively correlated with FGF21 levels in transfemales with 75(th) centile as cutoff. CONCLUSION: FGF21 levels correlated positively with serum triglycerides and serum LDL cholesterol in transfemales but not in transmales. Hence, FGF21 levels can be used as a marker for the development of metabolic syndrome in transfemales.