Correlation of Thyroid Gland Volume with Age and Gender in a Subset of Karachi Population

Abstract

Background: Thyroid gland volume (TGV) is highly variable as it is greatly influenced by age, gender, anthropometric measurements and geographical location. It has become essential for every population to determine reference range of their normal thyroid gland volume (TGV) in healthy individuals. This in turn will help the population in grading of goiter and will guide in large scale iodine monitoring programs. Objective: To determine TGV in a subset of Karachi population and to determine its association with age and gender. Methods: A cross-sectional study employing 421 volunteers aged 21 years and above went through the ultrasound (US) examination of their thyroid gland (TG) after being confirmed euthyroid by their serum thyroid stimulating hormones (TSH) evaluation. Results: TGV in the study was found to be 6.26 ± 2.89 ml. Males had significantly higher TGV 6.78 ± 2.88 ml as compared to females 5.7 ± 2.79 ml (P=0.00). Volume of right lobe was significantly greater than that of left lobe (P=0.00) in both the genders. TGV increased significantly with age till 60 years (P<0.05) and after the age of 60 years it decreased (P=0.035).. Conclusion: Mean volume of thyroid gland in this studied population is not only smaller than that of the Western countries but is also much smaller than the neighboring country Iran. The study has also proved that there was a significant decrease in mean thyroid gland volume after the age of 60 years. Prolonged and severe iodine deficient status of Pakistan till recent past could be an answer for small thyroid gland volume in the studied population. Similar studies in future will give more accurate facts and figures regarding mean thyroid gland volume in this population if Pakistan retains itself as an iodine sufficient State. Key Words: Thyroid Gland, Ultrasonography, Reference value, Goiter, Thyroid Hormones, Iodine.