Correlation of serum thyroid stimulating hormone with body mass index in healthy adults

Background: Obesity, a chronic disease that is increasing in prevalence in adults, adolescents and children, is now considered a global epidemic. Thyroid dysfunction contributes to the pathogenesis of obesity. Many clinical studies raise the questions of whether thyroid-stimulating hormone (TSH) changes in physiological limits is associated with obesity and whether there is a link between adipose tissue and hypothalamo-thyroidal axis. Materials and Method: This was a cross-sectional study. All clinically euthyroid patients and healthy volunteer adults of age 18 to 60 years of either gender were included in the study. Fasting blood sample was taken for thyroid function evaluation, which included Free T3, Free T4 and thyroid stimulating hormone. Height, weight, waist circumference and hip circumference were measured. The results were compared with calculated Body Mass Index (BMI). Results: 61 patients who met the inclusion criteria were studied. Among 61 patients 16 had subclinical hypothyroidism, 2 patients had hypothyroidism and 43 were euthyroid. Similarly, 2 underweight patients were observed, 7 had normal weight, 13 were over weight and 39 were obese. The mean TSH according to BMI were 3.8, 4.04, 3.88 and 6.19 respectively. Conclusion: The result in this study showed that the mean TSH increased as BMI increased with significant relationship between serum TSH and BMI (p <0.001). Thus thyroid dysfunction mainly subclinical hypothyroidism and hypothyroidism could be found in association with increased body weight.