INSULIN RESISTANCE AND BODY MASS INDEX WITH REGARD TO VARIOUS THYROID STIMULATING HORMONE REFERENCE INTERVALS

Neval Aksoy,Mustafa Taner Yeler,Zeynep Ozkan,Nilhan Nurlu Ayan,Ozden N Serin,Ali Ozkeskin

doi:10.12669/pjms.316.7560

Abstract

Objective:Previous studies have shown an association between thyroid function and insulin resistance and obesity. We compared insulin resistance and body mass index (BMI) in patients with normal TSH levels (2.5–4.2 µIU/mL), patients diagnosed with subclinical hypothyroidism, and healthy control subjects.Methods:The study included 104 subjects and was conducted at the Taksim Education and Research Hospital. The subjects were divided into three groups according to TSH levels: Group 1 (high-normal), TSH levels were 2.5–4.2 µIU/mL (n=33); Group 2 (subclinical hypothyroidism), TSH levels were 4.2–10 µIU/mL (n=42); and Group 3 (healthy control), TSH levels were 0.27–2.5 µIU/mL (n=29). The fT3 and fT4 levels were within normal limits in all groups. Insulin resistance and BMI were compared among groups. The homeostasis model assessment of insulin resistance (HOMA-IR) was used to estimate insulin resistance.Results:HOMA-IR and BMI were not significantly different among groups (p>0.05). A significant positive correlation was found between BMI and HOMA-IR in the high-normal TSH (p>0.059) and subclinical hypothyroidism (p>0.05) groups.Conclusions:HOMA-IR and BMI are important for the assessment of diabetes and cardiovascular diseases. We found no significant difference in HOMA-IR and BMI values among the three TSH reference range groups.

Highlights

Hypothyroidism is a clinical syndrome caused by reduced thyroid hormone secretion from the thyroid gland
Patients diagnosed with hyperthyroidism and receiving antithyroid treatment, or those diagnosed with diabetes mellitus (DM), chronic renal or liver disease, congestive heart failure or any other systemic illness, or receiving any hormone treatment were excluded from the study
The 104 subjects included in the study were divided into three groups according to thyroid stimulating hormone (TSH) levels: Group 1, TSH levels were 2.5–4.2 μIU/mL (n=33); Group 2, TSH levels were 4.2–10 μIU/mL (n=42); and Group 3, TSH levels were 0.27–2.5 μIU/mL (n=29)

Summary

INTRODUCTION

Hypothyroidism is a clinical syndrome caused by reduced thyroid hormone secretion from the thyroid gland. Hyporthyroidism is more common in females than males and its prevalence increases with age.[2] Subclinical hypothyroidism is the most common thyroid dysfunction and is usually asymptomatic; findings suggestive of hypothyroidism may be seen in 30% of patients.[3,4] Some studies suggested that the upper normal TSH limit can be reduced which level about 2.0-2.5 mU/L.5,6 In their investigation of the association of TSH levels with vascular disease and high cholesterol, Volzke et al.[7] found that patients with TSH levels between 2.5 and 4 mU/L were at increased risk of cardiovascular disease. We compared HOMA-IR and BMI values in patients with high-normal TSH levels, those with subclinical hypothyroidism, and in euthyroid healthy control subjects

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CONCLUSION