Abstract
Introduction: Hypothyroidism is frequently accompanied by insulin resistance and an unfavorable lipid profile, which may increase cardiometabolic risk. Interleukin-37 (IL-37) is an anti-inflammatory cytokine with proposed roles in immune and metabolic regulation; however, its relationship with dyslipidemia in hypothyroid patients with insulin resistance remains insufficiently understood.
Objectives: study examines the association between circulating IL-37 concentrations and lipid-profile parameters in this population.
Materials and Methods: This prospective cross-sectional study was conducted between December 2024 and August 2025 among 25 newly diagnosed adults with hypothyroidism and insulin resistance recruited from two hospitals in Thi-Qar Governorate, Iraq. Demographic and clinical data were collected, and fasting blood samples were analyzed for thyroid function, insulin resistance, serum IL-37, and lipid-profile parameters, including triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and very-low-density lipoprotein cholesterol (VLDL-C). Associations between circulating IL-37 levels and lipid parameters were examined using Pearson correlation and linear regression analyses, with multivariable models adjusted for age, sex, and body mass index (BMI).
Results: Twenty-five newly diagnosed patients with hypothyroidism and insulin resistance were included; 60% were women, and the mean age was 36.5 years. Circulating IL-37 concentrations were positively correlated with TG, total cholesterol, LDL-C, and VLDL-C, whereas an inverse correlation was observed with HDL-C. In linear regression analyses, IL-37 was significantly associated with all lipid-profile parameters in unadjusted models. After adjustment for demographic characteristics, the positive associations with TG, total cholesterol, LDL-C, and VLDL-C remained significant; however, the association with HDL-C was no longer statistically significant.
Conclusion: In newly diagnosed patients with hypothyroidism and insulin resistance, higher circulating IL-37 levels were associated with an adverse lipid profile. These findings suggest that IL-37 may reflect the inflammatory–metabolic disturbance underlying dyslipidemia and potentially heightened cardiovascular risk in this clinically vulnerable population.