Assessment of thyroid function in children, adults and pregnant and lactating women after long-term salt iodisation measurements

• Published in: British journal of nutrition 2018-06, Vol.119 (11), p.1245-1253
• Main Authors: Su, Xiaohui, Li, Mu, Liu, Lixiang, Shen, Hongmei, Kelly, Patrick J., Wang, Yanling, Chen, Zhihui, Wang, Jinbiao, Li, Weidong, Chen, Huixin, Xiao, Bangzhong, Han, Yunfeng, Liu, Shoujun, Liu, Peng
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Adults; Antibodies; Autoantibodies - blood; Child; Children; Children & youth; China - epidemiology; Cross-Sectional Studies; Disease control; Female; Hormones; Humans; Hyperthyroidism; Hypothyroidism - epidemiology; Hypothyroidism - prevention & control; Iodine; Iodine - administration & dosage; Iodine - urine; Lactation - physiology; Male; Middle Aged; Nutrition; Nutritional Endocrinology; Populations; Pregnancy; Provinces; Rural areas; Salt; Salts; Sodium Chloride, Dietary - administration & dosage; Thyroglobulin; Thyroglobulin - immunology; Thyroid; Thyroid gland; Thyroid Gland - drug effects; Thyroid Gland - physiology; Womens health; Young Adult
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114518000570

Universal salt iodisation (USI) has been successfully implemented in China for more than 15 years. Recent evidence suggests that the definition of ‘adequate iodine’ (100–199 µg/l) be revised to ‘sufficient iodine’ (100–299 µg/l) based on the median urinary iodine concentration (MUI) in school-age children. The objective of this study was to determine the prevalence of thyroid dysfunction in populations after long-term salt iodisation and examine whether the definition of adequate iodine can be broadened to sufficient iodine based on the thyroid function in four population groups. A cross-sectional survey was conducted in six provinces in the northern, central and southern regions of China. Four population groups consisting of 657 children, 755 adults, 347 pregnant women and 348 lactating women were recruited. Three spot urinary samples were collected over a 10-d period and blood samples were collected on the 1st day. In the study, among the adults, pregnant women and lactating women, the prevalence rates of elevated thyroglobulin antibody and thyroid microsomal antibody levels were 12·4, 8·5 and 7·8 %, and 12·1, 9·1 and 9·1 %, respectively. Abnormally high thyroid dysfunction prevalence was not observed after more than 15 years of USI in China because the thyroid dysfunction rates were all