Determination of Relationship between Thyroid Gland Volume and Anthropometric Indices

Abstract

Objective: To sonographically determine the thyroid gland volume in normal adults in Jos University Teaching Hospital, as well as how it relates to anthropometric factors. Background: The thyroid gland is one of the largest endocrine glands in the body weighing about 10-25g.  It regulates the rate of metabolism and controls the growth and rate of function of many other systems in the body. These it does, by producing thyroid hormones, principally thyroxine (T4) and triiodothyronine (T3). The accurate estimation of the size of the thyroid is very important for the evaluation and management of thyroid disorders. Thus, knowing the normal size in a geographic location would form a baseline for detecting abnormalities. Ultrasonography is a cheap, readily available, easy to perform and non-invasive method to image the thyroid gland, hence its use in this resource-limited setting. Methods: This is a cross-sectional study of sonographic measurement of thyroid gland volume on 400 normal (healthy) adults in Jos, Plateau State, Northern part of Nigeria. All examinations were performed using LOGIC 5, a real-time ultrasound machine using a 10MHZ linear transducer and ultrasound transmission gel to act as a coupling gel. Measurements of each lobe and isthmus were obtained in longitudinal (length), transverse (width) and depth(breath) in centimetres (cm). Blood samples were taken for thyroid function tests. The weight and heights were obtained. The data obtained were statistically analyzed using SPSS software version 17. The results were presented in forms of tables, graphs and chart. Results: The mean thyroid volume for males   6.03 cm3±2.22 was higher than that of females 5.62 cm3±2.14. The mean right lobe volume (RLV) was 3.09 cm3±1.47 and that of males and females were 3.16 cm3 ±1.34 and 3.04 cm3 ±1.55 respectively. The mean left lobe volume (LLV) was 2.69 cm3 ± 1.37 and that of males and females were 2.89 cm3±1.32 and 2.57 cm3±1.39 respectively. The right lobe volume was significantly greater than the left lobe(p=0.000). The total mean isthmus volume was 0.27 cm3±0.31. The mean isthmus volume in males 0.3±0.28 is significantly higher than that of females 0.24±0.23 (p=0.025). The BMI increases in females with increasing age. BMI and BSA are higher in males. Conclusion: The volume obtained in this study was slightly lower than those reported by previous studies in Nigerian adults. The right lobe volume was higher than that of the left and the volume was higher in males compared to females. Anthropometric parameters were noted to affect the thyroid volume.