Investigation on water iodine level and iodine nutritional status in excessive iodine intaking areas in 2015 - 2016 in Liaocheng City Shandong Province

Abstract

Objective To investigate the status of iodine content in the inner and outer environment of residents in excessive iodine intaking areas in Liaocheng of Shandong Province after stop taking iodized salt. Methods Totally 300 residents from each county (city) were selected for semi-quantitatively examination of their household salt in seven excessive iodine intaking counties (cities) in 2015 and 2016. Five counties were surveyed in 2015, and two other counties were surveyed in 2016. Then one town was selected from every county (city) as test site, one hundred children aged 8 - 10 (50 males and 50 females) from every test site were selected to measure their household salt iodine level. If the household salt was confirmed a non-iodized salt, water samples and urine samples were collected. Water iodine and urinary iodine contents were measured by arsenic cerium catalytic spectrophotometry (WS/T 107-2006). Results In 2015 and 2016, non iodized salt rates were 97.4% (1 753/1 800) and 96.6% (1 738/1 800), respectively in Liaocheng. Totally 686 household drinking water samples were measured. The water iodine levels were 2.7 - 748.4 μg/L, and the median was 203.4 μg/L. Totally 699 urine samples were measured. The urine iodine levels were 33.6 - 1 692.0 μg/L, and the median was 486.8 μg/L. The median of children's household water iodine level and median of children's urinary iodine level were significantly positively correlated (r = 0.857, P < 0.05). Conclusions The measurement of stop taking iodized salt in excessive iodine intake areas in Liaocheng is well implemented. Some monitoring sites show significant improvement. However, the urine iodine level of most residents is still high. The harmful effects of excessive iodine intaking are still constantly existed in some areas. In the future, in addition to continue to change the water to reduce iodine, it is also necessary to strengthen the health education of residents to improve the residents' awareness of the dangers of excessive iodine. Key words: Iodine; Water; Urine