INS and metabolic syndrome: Significant associations were also observed between GDF15 and components of metabolic syndrome, specifically, levels of serum triglycerides (beta = 0.13, p-value = 2.4 × 10–22), fasting insulin (beta = 0.10, p-value = 1.2 × 10–13) and waist-to-hip ratio (WHR) (beta = 0.049, p-value = 7.0 × 10–10).