Factors influencing thyroid volume and comparative analysis of thyroid volume correction methods in children aged 8-10 years in Gansu, China.

Abstract

Background and objectives: This study aimed to analyze the relationship between thyroid volume (TVOL) and physical development of children, and explore the suitable TVOL correction methods.

Methods and study design: 1500 children aged 8-10 years from Gansu province northwest China were selected. The height (H), weight (W), urine iodine of children was measured and their thyroid was examined by ultrasound. Body mass index (BMI), body surface area (BSA) and TVOL were calculated (BSA calculated by three formulas). The relationship between TVOL and age, sex, physical development was analyzed. The applicability of TVOL correction methods including BMI corrected volume (BMIV), BSA corrected volume (BSAV), weight and height corrected volume indicator (WHVI) and height corrected volume indicator (HVI) were compared.

Results: Median urinary iodine concentrations of children aged 8, 9, 10 years were 166.6 μg/L, 167.2 μg/L and 178.8 μg/L respectively. The rate of iodine deficiency was 20.3%, the rate of thyroid goiter was 3.2%. Physical development indexes (height, weight, BMI and BSA) and TVOL increased with age. Also, physical development indexes (height, weight, BMI and BSA) of boys were higher than girls (p <0.05). Only BSAV1 had no correlation with all physical development indexes (p >0.05). The TVOL P97 (97th percentile) of children aged 8, 9, 10 years were 4.4 ml, 4.9 ml, 6.5 ml, the values were 4.6 mL, 4.7 mL, 5.9 mL after BSAV1 corrected. The difference between TVOL and BSAV1 ranges from -0.37% to 0.36%.

Conclusions: The thyroid volume is not only affected by age, but it is also affected by physical development. Thyroid goiter should be assessed based on age and physical development. The formula BSAV1=TVOL/ (W0.425×H0.725×71.84×10-4) was a suitable TVOL correction method.