Wen Chen1,2, Qi Zhang1, Yalan Wu1, Wei Wang1, Xiaoming Wang3, Elizabeth N Pearce4, Long Tan1, Jun Shen1, Wanqi Zhang1,2,5. 1. 1 Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, P.R. China. 2. 2 Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China. 3. 3 The Shandong Institute for Endemic Disease Control and Research, Shandong, P.R. China. 4. 4 Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, Massachusetts. 5. 5 Tianjin Key Laboratory of Environment, Nutrition and Public Health; Center for International Collaborative Research on Environment, Nutrition and Public Health; Public Health School of Tianjin Medical University, Tianjin, China.
Abstract
BACKGROUND: The iodine nutritional status of the Chinese population has been greatly improved in recent years. Therefore, the reference values for thyroid volume (Tvol) in children with sufficient iodine intake need to be updated. The study aimed to update the reference values for Tvol in children with sufficient iodine intake in order to define goiter in the context of sustained iodine sufficiency. METHODS: A cross-sectional study was conducted in children with sufficient iodine intake in China. Twice-repeated 24-hour urine samples were collected from each child to estimate habitual daily iodine intake. Serum thyroid function tests were measured. Tvol was assessed by ultrasound. From the sample of euthyroid children with sufficient iodine intakes, the 50th and 97th percentiles for Tvol by age and body surface area (BSA) were calculated using quantile regression. RESULTS: A total of 679 children aged 8-13 years with sufficient iodine intake (188 μg/day [145-235 μg/day]) were included in the analysis. The mean Tvol of the children was 4.1 ± 1.6 mL, and no differences were found between boys and girls in any age or BSA group. Quantile regression models demonstrated that BSA was a strong positive predictor of Tvol (p < 0.0001), while age only had a significant effect on median Tvol (p = 0.013). Sex was not a significant predictor of Tvol in children. CONCLUSIONS: The reference values for Tvol in Chinese children have been updated. This study indicates that the upper limit of (97th percentile) Tvol was dependent on BSA, while the median Tvol was determined by both age and BSA.
BACKGROUND: The iodine nutritional status of the Chinese population has been greatly improved in recent years. Therefore, the reference values for thyroid volume (Tvol) in children with sufficient iodine intake need to be updated. The study aimed to update the reference values for Tvol in children with sufficient iodine intake in order to define goiter in the context of sustained iodine sufficiency. METHODS: A cross-sectional study was conducted in children with sufficient iodine intake in China. Twice-repeated 24-hour urine samples were collected from each child to estimate habitual daily iodine intake. Serum thyroid function tests were measured. Tvol was assessed by ultrasound. From the sample of euthyroid children with sufficient iodine intakes, the 50th and 97th percentiles for Tvol by age and body surface area (BSA) were calculated using quantile regression. RESULTS: A total of 679 children aged 8-13 years with sufficient iodine intake (188 μg/day [145-235 μg/day]) were included in the analysis. The mean Tvol of the children was 4.1 ± 1.6 mL, and no differences were found between boys and girls in any age or BSA group. Quantile regression models demonstrated that BSA was a strong positive predictor of Tvol (p < 0.0001), while age only had a significant effect on median Tvol (p = 0.013). Sex was not a significant predictor of Tvol in children. CONCLUSIONS: The reference values for Tvol in Chinese children have been updated. This study indicates that the upper limit of (97th percentile) Tvol was dependent on BSA, while the median Tvol was determined by both age and BSA.