Iodine status in vulnerable groups of Linxia Hui Autonomous Prefecture, China

Abstract

To assess iodine status in vulnerable groups of Linxia Hui Autonomous Prefecture, China. We selected 5 villages in the east, south, west, north and center of 8 counties of Linxia Hui Autonomous Prefecture randomly. In each village, one primary school was identified and 80 students aged 8-10 years were randomly selected. At the same time, 20 pregnant women, 20 lactating women, 20 women of childbearing age and 20 young children (0-3 years) were randomly selected via existing township health center lists. The iodine content of household salt and drinking water and the urine in four population subsets (except school-aged children) was measured. The thyroids were examined in school-aged children. The iodine content in most household drinking water (90.2%) was less than 10μg/L. The percentage of households using adequately iodized salt was 83.2% and percentage of households using non-iodized salt was as high as 15%. The median urinary iodine concentration (UIC) of pregnant and lactating women, and women of child-bearing age was 89, 85 and 90μg/L, respectively, indicating an iodine deficiency. The median UIC of 0-3 year old babies was 107μg/L. The goiter rates of school-aged children were 10.6% by ultrasound and 9.9% by palpation. Low median UIC and high goiter rates were observed most frequently in counties with higher non-iodized salt and higher percentage of minority nationalities. Iodine deficiency has been a significant public health problem in Linxia Hui Autonomous Prefecture and still exists. Iodine supplement is needed to ensure adequate iodine nutrition for at-risk groups.

Keywords

• Iodine deficiency, iodized salt, goiter, urine iodine concentration

References

1. WHO/ICCIDD/UNICEF. Assessment of the iodine deficiency disorders and monitoring their elimination. 3rd edition. Geneva: WHO; 2007.
2. WHO/UNICEF/ICCIDD (1999). Progress towards the elimination of iodine deficiency disorders Geneva: WHO document WHO/NHD/99.4
3. WHO/UNICEF/ICCIDD. Global prevalence of iodine deficiency disorders. Micronutrient deficiency information system working paper No.1. Geneva: WHO, 1991.
4. Chen ZP. IDD hazard control progress and challenge. Geriatr Health Care 2010; 16: 6-11.
5. Chen ZP. Progress of IDD elimination in China. J Prev Med Inf 2000; 16: 93-94.
6. Pino S, Fang SL, Braverman LE. Ammonium persulfate: a new and safe method for measuring urinary iodine by ammonium persulfate oxidation. Exp Clin Endocrinol Diabetes 1998; 106: 22-27.
7. China’s Ministry of Health. The recommended method for measuring iodine in drinking water. Ministry of Health, Beijing. 2001, Document No. 161 (in Chinese).
8. Liu LJ, Yin J, Zheng ZH. Determination of iodine in urine mild and vigorous digestion methods followed by ceric arsenite reaction. Chinese J Endemiology 1995; 14: 37-39.

9. WHO/UNICEF/ICCIDD (1996). Recommended iodine levels in salt and guidelines for monitoring their adequacy and effectiveness. Geneva: WHO.
10. WHO/UNICEF/ICCIDD. Reaching optimal iodine nutrition in pregnant and lactating women and young children. IDD NEWSLETTER 2008; 27: 1-3.
11. State Bureau of Quality Technical Supervision. The normal value of thyroid volume in children and adolescents. Chinese Criteria Publishing House, Beijing. 1996, GB16398-1996 (in Chinese).
12. China’s Ministry of Health and State Bureau of Quality Technical Supervision. The Criteria of Elimination of IDD. Chinese Criteria Publishing House Beijing: 1995, GB16006-1995(in Chinese). Wang Y, Zhang Z, Ge P, Wang Y, Wang S. Iodine deficiency disorders after a decade of universal salt iodization in a severe iodine deficiency region in China. Indian J Med Res 2009; 130: 413-417.
13. Gordon RC, Rose MC, Skeaff SA, et al. Iodine supplementation improves cognition in mildly iodinedeficient children. Am J Clin Nutr 2009; 90: 1264 12
14. Wang Y, Zhang Z, Ge P, Wang Y, Wang S. Iodine status and thyroid function of pregnant, lactating women and infants (0-1 yr) residing in areas with an effective Universal Salt Iodization program. Asia Pac J Clin Nutr 2009; 18: 34-40.