GDF15 and metabolic syndrome: MetS women showed significantly higher serum levels of FGF21 (215.0 ± 120.6 vs. 126.2 ± 91.5 pg/mL) and GDF15 (585.3 ± 243.7 vs. 427.0 ± 114.6 pg/mL) than the age-matched healthy women.