Influencing factors of thyroid volume in school-age children aged 8 - 10 years in Xinjiang Uygur Autonomous Region in 2020 / 中华地方病学杂志

ABSTRACT

Objective:To investigate the influencing factors of thyroid volume in school-age children aged 8 - 10 years in Xinjiang Uygur Autonomous Region (Xinjiang for short).Methods:In 2020, counties (cities, districts) were taken as the units in the whole region of Xinjiang. Each county (city, district) was divided into 5 sampling areas according to the orientation of east, west, south, north, and middle, one township/street was selected from each area, and one primary school was selected from each township/street, 40 non-boarding children aged 8 - 10 years were selected from each primary school as the investigation subjects. Height and weight of children were measured, and body mass index (BMI) and body surface area were calculated; 24 h mixed urine samples of children and household edible salt samples were collected to detect the contents of urinary iodine and salt iodine; thyroid volume of children was measured by B-ultrasonography. Pearson correlation analysis was used to analyze the correlation between thyroid volume and age, height, weight, body surface area, BMI, urinary iodine content, and salt iodine content. Univariate and multiple linear regression analyses were used to evaluate the correlation variables affecting thyroid volume.Results:A total of 18 334 children aged 8 - 10 years were investigated. The median urinary iodine was 237.88 μg/L. There were 132 children with goiter, and the rate of goiter was 0.72%. Of these, 9 249 (50.45%) were girls and 9 085 (49.55%) were boys. Girls' thyroid volume was positively correlated with age, height, weight, body surface area, BMI, urinary iodine content, and salt iodine content ( r = 0.125, 0.135, 0.167, 0.167, 0.154, 0.031, 0.019, P < 0.05); boys' thyroid volume was positively correlated with age, height, weight, body surface area, and BMI ( r = 0.132, 0.326, 0.156, 0.149, 0.146, P < 0.05), and there was no correlation with urinary iodine content and salt iodine content ( r = 0.019, 0.017, P > 0.05). Univariate linear regression analysis showed that age, height, weight, BMI, body surface area and urinary iodine content were the influencing factors of thyroid volume ( t = 14.92, 12.54, 20.98, 17.98, 20.25, 4.28, P < 0.01). Further multiple linear regression analysis showed that age, BMI, body surface area and urinary iodine content had significant independent effects on thyroid volume ( t = 9.61, 8.57, 7.76, 4.89, P < 0.01), the coefficient of determination ( R2) of the model was 0.278 2. According to the regression coefficient (β), the body surface area (β = 0.522 6) had the greatest influence on thyroid volume. Conclusions:The iodine nutrition of children aged 8 - 10 years in Xinjiang is sufficient. Thyroid volume is affected by age, BMI, body surface area and urinary iodine content.