INS and metabolic syndrome: Among the eight secondary bile acids, only glycolithocholate sulfate was inversely associated with MetS traits including the LDL-C (β = −0.018, p = 1.8 × 10−13), triglycerides (β = −0.011, p = 0.017), and insulin level (β = −0.032, p = 3.8 × 10−8), BMI (β = −0.008, p = 9.9 × 10−8).