Comparative analysis of the survey results of iodine deficiency disorders between high-risk areas in Chongqing and in Linzhi of Tibet in 2007 / 中国地方病学杂志

ABSTRACT

Objective To investigate iodine deficiency disorders(IDD) in Chongqing and Linzhi, and to provide scientific basis for IDD control and prevention. Methods According to the national program developed in 2007, investigation was conducted in Chengkou and Wuxi county in Chongqing municipality, and Linzhi, Bomi,Milin and Langxian county in Linzhi prefecture. Five towns were sampled in Linzhi county, and 3 in other counties.In each town, one township primary school and two village primary schools were selected to inspect thyroid by B ultrasound and palpation, and urinary iodine of children aged 8 to 10 years was tested in these schools. Meanwhile,2 villages were selected in each town for test of salt iodine level and urinary iodine of childbearing age women and search cretin cases. Results Three hundred and forty families in Chongqing and 915 families in Linzhi were investigated. The coverage of iodized salt in Chongqing was 98.82%(336/340), which was significantly higher than that in Linzhi[66.34%(607/905), x2 = 139.56, P ＜ 0.01]. Goiter rate of children in Chongqing was 9.27%(89/960) by palpation and 8.34% (61/731) by B ultrasound, while goiter rate of children in Linzhi was 7.80%(102/1308) by palpation and 5.53% (69/1248) by B ultrasound. The difference of goiter rate by palpation between Chongqing and Linzhi was not statistically significant (x2 = 1.37, P ＞ 0.05 ). But goiter rate of children by B ultrasound in Chongqing was higher than that in Linzhi (x2= 5.51, P ＜ 0.05). In Chongqing, the median urinary iodine was 319.15 μg/L, and 345.75 μg/L in Chengkou county and 281.39 μg/L in Wuxi county. In Linzhi prefecture, the median urinary iodine was 189.81 μg/L, and 207.81 μg/L in Linzhi county, 161.12 μg/L in Bomi county, 131.83 μg/L in Milin county and 334.60 μg/L in Langxian county. The median urinary iodine in childbearing women were 248.42 μg/L in Chongqing and 121.25 μg/L in Linzhi. The median urinary iodine in Chongqing both in children and women were higher than those in Linzhi. No new cretin case was found in these two areas. Conclusions Goiter rate in high risk areas of IDD in Chongqing and Linzhi has decreased to less than 10%.No new cretin case is found in these areas. It can be concluded that the work of control and prevention is effective.There is excess iodine in Chongqing. In Linzhi county and Langxian county, iodine is excess in children and deficient in women. Further investigation should be conducted to find out the reason. Population iodine is excess in Bomi and Milin counties. The concentration of salt iodine should be decreased in Chongqing. In Linzhi prefecture,adding iodine measures should be adjusted based on further investigation.