Evaluation of prevention and control of iodine deficiency disorder in Jiaojiang district, Taizhou city, Zhejiang province, 1995 - 2009

Objective To understand the effect of prevention and control of iodine deficiency disorder (IDD) by iodized salt. Methods One primary school and 4 villages were randomly selected respectively in the townships located in the east, south, west, north and central parts of the district to conduct surveillance among local children aged 8-10 years and households selected by probability proportional to size sampling. Thyroid was check by palpation; urinary iodine concentration was measured by As-Ce catalytic spectrophotometry, salt iodine content was detected by direct titration. The evaluation indicators of IDD elimination of IDD included: qualified iodized salt use rate of household; median of urinary iodine; goiter rate, awareness rate of knowledge of IDD. Results A total of 1287 people were surveyed in 1995 before iodized salt intervention, 151 goiter cases were found, the goiter rate was 11.7% and the sickness rate was 0.8%. The median of urinary iodine was 109.4 g/L. A total of 8781 people were surveyed during 1996 - 2009 after iodized salt intervention, 523 goiter cases were found, the goiter rate was 1.2%-10.2%(2=142.152, P=0.001)and the sickness rate was 0-0.3% ＞ the median of urinary iodine was 168.7-293.0 g/L. A total of 5833 iodized salt samplers were detected, 4816 were qualified. The coverage of iodized salt was 89.1%, the qualified rate of iodized salt was 92.7%, the qualified iodized salt use rate was 82.6%. The average iodine content of iodized salt was 42.3 mg/kg, the standard deviation was 5.8, the coefficient of variation was 13.8% and the 95% confidence interval of population mean was 41.6-42.9 mg/kg. The survey of daily salt intake was conducted among 784 people, the average daily salt intake was 8.2 g. The goiter rate in 2009 was lower than that in 1995 (2=26.881, P=0.001), the difference on sickness rate was without statistical significance (2=0.806, P=0.4), The median of urinary iodine in 2009 was higher than that in 1995 (u=8.507, P＜0.01), the qualified iodized salt use rate in 2009 was higher than that in 1996 (2=151.414, P=0.001). Conclusion The effect of IDD prevention and control was significant in Jiaojiang, all the indicators met the requirement of IDD elimination and the urine iodine concentration in children was appropriate.