An investigation of the iodine status among children aged from 8-10 in both urban and rural areas of Xiamen after 3 years promotion of new standard iodized salt.

Abstract

Objective To investigate the coverage of iodized salt and the iodine status among children aged from 8-10 years in both urban and rural areas of Xiamen after promotion of new standard iodized salt, and to provide scientific evidence for adjustment of control strategy. Methods After 3 year promotion of new standard iodized salt, Huli and Xiang'an were selected as the urban and rural investigation sites, respectively in 2015. Each investigation site was further divided into five sampling areas, namely east, west, south, north and central. In each sampling area, one town was randomly selected and 2 tapping water samples were collected to determine the iodine level; in each town, 4 villages were randomly selected and 15 residents were selected and edible salt samples were collected to determine the iodine level. Moreover, one primary school was selected in each town, and 40 children aged from 8-10 years old were randomly selected to perform thyroid examination and urinary iodine level determination. The water iodine was detected by arsenic cerium catalytic spectrophotometry; salt iodine was detected by direct titration; urinary iodine was detected by arsenic cerium catalytic spectrophotometry; thyroid was examined by B ultrasound. Results The iodine concentration was lower than 10 μg/L in drinking water in both urban and rural areas. The coverage rate of iodized salt in urban and rural areas was 99.3% (298/300) and 94.0% (282/300), respectively. The consumption rate of qualified iodized salt was 93.7% (281/300) and 90.7% (272/300), respectively. The prevalence of goiter was 3.8% (8/210) both in urban and rural areas. The prevalence of thyroid nodule was 17.6% (37/210) and 19.5% (41/210), respectively. No significance was found when comparing the prevalence of goiter and the prevalence of thyroid nodule (χ2= 0.000, 0.252, all P > 0.05). The median of urinary iodine was 208.9 and 167.2 μg/L, respectively. The statistical analysis found that the urban children had higher iodine level when comparing with rural counterparts (Z= 4.030, P 0.05). The prevalence of thyroid nodule in male and female children was 13.5% (28/208) and 23.6% (50/212), respectively, the analysis showed that the female children had higher prevalence of thyroid nodule (χ2= 7.115, P < 0.01). The median of urinary iodine in male and female children was 197.8 and 169.6 μg/L, respectively, and the urinary iodine level was significantly higher in male when comparing with female children (Z= 2.218, P < 0.05). Conclusions After promotion of new standard iodized salt, the iodine nutrition of children aged from 8-10 years in both urban and rural areas of Xiamen were good. The goal of eliminating iodine deficiency disorders was achieved. The iodine supplement measure should be further promoted to ensure the adequate level of iodine in residents, adhere to the iodine supplement measure, promote a healthy lifestyle, ensure the amount of iodine intake. Key words: Iodine; Deficiency diseases; Urine; Salts; Child; Thyroid