Adipocyte Fatty Acid Binding Protein Level Among Patients with Subclinical Hypothyroidism

Background: Subclinical hypothyroidism (SCH) is diagnosed when free thyroxine (fT4) level is normal and thyroid stimulating hormone (TSH) level is elevated. The prevalence of SCH is 3-15%. Adipocyte fatty acid binding protein (A-FABP) is an adipokine secreted from adipose tissue. It has a role in the regulation of lipid storage, oxidation and lipolysis. Atherogenic indices of plasma are lipid ratios that are used in predicting cardiovascular events. They include atherogenic index of plasma, Castelli’s risk indexes I and II and atherogenic coefficient. Objectives: The study was aimed to evaluate serum A-FABP level among SCH patients compared to a control group. Materials and method: A cross-sectional study was conducted at Azadi teaching Hospital/ Duhok city started from Nov, 2022 until Dec, 2023. It included 160 participants, 80 were newly diagnosed SCH cases and 80 were apparently healthy control. Venous blood samples were obtained from each participant for the following biochemical tests: TSH, fT3, fT4, anti-thyroid peroxidase antibody, lipid profile and serum A-FABP. All analytes were measured using Cobas 6000 (Roche-HITACHI) except for A-FABP that was measured using ELISA.Results: The majority of the participants were aged less than 40 years (78.8%) with females’ predominance (75%). The mean BMI (28.4 kg/m2) and waist circumference (91.7 cm) of patients were significantly higher than control participants (p = 0.035) and (p = 0.033) respectively. No significant differences were detected between cases and controls in the mean of total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. No significant differences were detected of atherogenic indices between the cases and controls. The mean A-FABP level among cases (3.11 ng/ml) was significantly (p = 0.030) higher than that of the control group which was 2.63 ng/ml. Conclusion: The mean level of serum A-FABP was significantly higher among patients with SCH compared to healthy control group.