Iodine nutrition and goiter prevalence among children at ages of 8 to 10 years in Zhejiang Province / 预防医学

ABSTRACT

Objective@#To investigate the status of iodine nutrition and prevalence of goiter among children at ages of 8 to 10 years in Zhejiang Province in 2021, so as to provide insights into the management of iodine deficiency in children.@*Methods @#A total of 90 counties (districts) were sampled as field survey sites from 11 cities of Zhejiang Province using a multi-stage stratified random sampling method in 2021, and non-residential children at ages of 8 to 10 years in these sites were sampled as study subjects. Subjects' household edible salt samples and random urine samples were collected. The iodine content in salt and urinary iodine level were determined using the direct titration method and arsenic-cerium catalytic spectrophotometry for evaluation of iodine nutrition among children. In addition, the lateral lobe of the thyroid gland was measured using ultrasound, and the prevalence of goiter was estimated. @*Results@#A total of 19 363 children were recruited, including 9 710 male children and 9 653 female children, with a male to female ratio of 1.01︰1, and there were 10 704 urban children (55.28%) and 8 659 rural children (44.72%), 9 149 children living in coastal areas (47.25%) and 10 214 children in inland regions (52.75%). The mean iodine content was (19.79±9.25) mg/kg in salt, and the coverage of qualified iodized salt (15 252) was 78.77%. The coverage of qualified iodized salt was significantly lower in urban children than in rural children (76.70% vs. 81.21%; χ2=68.301, P<0.001), and was lower in children living in coastal regions than in inland regions (68.05% vs. 88.27%; χ2=1 270.769, P<0.001). The median urinary iodine concentration was 195.1 μg/L, and the household iodine content in salt correlated positively with urinary iodine concentration in children (rs=0.383, P<0.001). There were 2 885 children with iodine deficiency (14.90%), 7 137 children with adequate iodine (36.86%), 5 414 children with excessive iodine intake (27.96%), and 3 927 children with iodine overdose (20.28%), and the distribution of iodine nutrition in children varied significantly in regions (χ2=283.277, P<0.001) and gender (χ2=126.349, P<0.001). The prevalence of goiter was 2.45% among 7 195 children receiving ultrasound examinations, and a higher prevalence rate of goiter was detected in urban children than in rural children (2.76% vs. 2.00%; χ2=3.962, P=0.047). @*Conclusions @#The overall urinary iodine nutrition was adequate among children at ages of 8 to 10 years in Zhejiang Province in 2021, and the prevalence of goiter in children fell within the threshold defined in the criteria of elimination of iodine deficiency. However, the supervision of the iodized salt quality remains to be improved and iodine deficiency control remains to be reinforced.