Iodine nutritional status among the population before and after implementation of a new standard of edible iodized salt in Wuwei City of Gansu Province / 中华地方病学杂志

ABSTRACT

Objective To explore the iodine nutritional status of all people after the practice of new standard of edible iodized salt, to assess whether the new standard of edible iodized salt can satisfy the iodine nutrition need in different populations, and to provide a scientific basis for supplementation of iodine. Methods Before and after the implementation of new salt iodine concentration, in 2009 and 2015, a contrastive study was performed in 1 243 people(including 402 children aged 8 to 10 years,408 adults aged 18 to 45 years,211 pregnant women and 222 lactating women) who lived in urban and rural areas of Wuwei City. Random urine samples were collected to measure the urinary iodine in all populations and household salt samples were collected. Urinary iodine was detected by arsenic cerium catalytic spectrophotometry(WS/T 107-2006).The iodine level in salt was determined by direct titration(GB/T 13025.7-2012).Results Before and after the implementation of new iodine salt standard, the coverage of adequately iodized salt was consistently higher than 94%, the qualified rate of iodized salt was consistently higher than 96%,the median of iodized salt was reduced from 31.0 mg/kg to 26.9 mg/kg;the medians of urinary iodine of children aged 8 to 10 years, adults, pregnant and breastfeeding women were reduced from 290.84, 225.52,200.42 and 180.65 μg/L to 187.37,174.96,159.99 and 152.88 μg/L;the ratios of urinary iodine which was less than 100 μg/L in children aged 8 to 10 years, adults and breastfeeding women were risen from 5.15% (10/194), 12.57% (24/191) and 16.19% (17/105) to 10.58% (22/208), 15.81% (34/215) and 33.33% (39/117); the ratio of urinary iodine which was less than 150 μg/L in pregnant women was risen from 39.78%(37/93)to 43.22%(51/118);the ratios of urinary iodine between 100 and 200 μg/L in children aged 8 to 10 years and adults were risen from 15.46% (30/194) and 30.37% (58/191) to 44.23% (92/208) and 43.26% (93/215); the ratios of urinary iodine greater than 300 μg/L in children aged 8 - 10, adults, pregnant and breastfeeding women were reduced from 47.94%(93/194),34.55%(66/191),29.76%(26/93)and 28.57% (30/105) to 17.31% (36/208), 19.07% (41/215), 16.95% (20/118) and 11.97% (14/117). Conclusion After the implementation of new salt iodine concentration standard,the iodine nutrition level has decreased in all groups and better suited for children aged 8 to 10 years and adults,but the risk of iodine deficiency is increased in pregnant and breastfeeding women.