Pandav C S, Mallik A, Anand K, Pandav S, Karmarkar M G
Centre for Community Medicine, All India Institute of Medical Sciences, New Delhi, India.
Natl Med J India. 1997 May-Jun;10(3):112-4.
Iodine deficiency disorders (IDDs) are an important cause of mental handicap and poor educability of children. Though Delhi does not lie in the classical Himalayan goitre belt, it has been shown that IDD was endemic in Delhi. Studies of school children in Delhi reported a total goitre rate of 55% which indicates severe endemicity. The sale of uniodized salt has been banned in Delhi since July 1989. This study was done five years later to assess the impact of this measure on IDD prevalence in Delhi.
A cross-sectional study was done among class VI students studying in government schools of Delhi. A complete list of government middle schools in Delhi was obtained and 30 were selected on the basis of 'probability proportion to size'. A sample size of 1200 was decided based on an expected prevalence of 50% with 5% error and design effect of three. All children in class VI of each school were clinically examined by a trained doctor for the presence of goitre and casual urine samples were collected in capped plastic tubes. The urinary iodine estimation was done by the wet ashing method.
The total goitre rate was 20.5%. If the results were limited to children in the age group of 10-12 years it was 19.7%. The urinary iodine was less than the recommended 100 micrograms/L of urine in 23.6% of the children; 7.6% had no iodine in the urine. It is possible that some children could have substituted water in place of urine. The median urinary iodine level was 198 micrograms/L of urine.
The study showed that IDD continues to be prevalent in mild endemic proportions. Compared to the results of previous surveys, the IDD rates have declined in the last few years. However, it continues to be an important public health problem in Delhi. It is essential to monitor the iodine content of salt on a regular basis. IDD control activities should be strengthened in Delhi and repeat surveys should be done every 3-5 years to monitor the progress achieved in eliminating IDD.
碘缺乏症（IDD）是导致儿童智力障碍和受教育能力低下的一个重要原因。尽管德里并不位于典型的喜马拉雅甲状腺肿带，但已有研究表明，碘缺乏症在德里呈地方性流行。对德里在校学生的研究报告显示，甲状腺肿总患病率为55%，这表明该病流行情况严重。自1989年7月起，德里已禁止销售未加碘盐。本研究在五年后开展，旨在评估这一措施对德里碘缺乏症患病率的影响。
对在德里政府学校就读的六年级学生进行了一项横断面研究。获取了德里政府中学的完整名单，并根据“规模概率比例”选取了30所学校。基于预期患病率50%、误差5%以及设计效应为3，确定样本量为1200。每所学校六年级的所有学生均由一名经过培训的医生进行临床检查，以确定是否存在甲状腺肿，并将随机尿液样本收集到有盖塑料管中。采用湿灰化法进行尿碘测定。
甲状腺肿总患病率为20.5%。若将结果限定在10至12岁年龄组的儿童中，则患病率为19.7%。23.6%的儿童尿碘低于推荐的每升尿液100微克；7.6%的儿童尿液中无碘。有可能一些儿童用清水替代了尿液。尿碘中位数水平为每升尿液198微克。
该研究表明，碘缺乏症仍以轻度地方性流行比例存在。与之前的调查结果相比，过去几年碘缺乏症患病率有所下降。然而，在德里它仍然是一个重要的公共卫生问题。定期监测盐中的碘含量至关重要。应在德里加强碘缺乏症控制活动，并每3至5年进行重复调查，以监测在消除碘缺乏症方面取得的进展。
