Objective:To investigate the iodine nutritional status of 8 to 10 years old school children in Linhai City, and to provide a theoretical basis for prevention and treatment of iodine deficiency.

Methods:From 2016 to 2018, in the townships and sub-district offices under the jurisdiction of Linhai City, one town (street) was selected according to its geographical distribution in the east, west, south, north, and middle five directions, and one central primary school was selected in each town (street). In each central primary school, 40 children aged 8 to 10 years were selected, 5 to 10 ml of urine samples were collected, and urinary iodine level was determined by arsenic cerium catalytic spectrophotometry.

Results:A total of 620 urine samples were detected in children, and the median urinary iodine was 172.5 μg/L. In 2016, 200 samples were tested, the median urinary iodine was 191.5 μg/L, 14.00% (28/200) for < 100 μg/L, and 20.00% (40/200) for ≥300 μg/L; in 2017, 210 samples were tested, the median urinary iodine was 174.5 μg/L, 18.10% (38/210) for < 100 μg/L, 11.90% (25/210) for ≥300 μg/L; in 2018, 210 samples were tested, the median urinary iodine was 149.0 μg/L, 24.29% (51/210) for < 100 μg/L, and 9.05% (19/210) for ≥300 μg/L. The differences in urinary iodine concentration between the three years were statistically significant (H=20.831, P < 0.05). A total of 310 boys were tested urinary iodine level, with a median of 147.5 μg/L, and 310 girls were tested with a median of 119.5 μg/L. The difference in urinary iodine concentration between boys and girls was statistically significant (Z=2.766, P < 0.05).

Conclusion:The iodine nutritional level of 8 to 10 years old school children in Linhai City is within the appropriate range (100-199 μg/L), but the monitoring of urinary iodine should continue.