|Year : 2012 | Volume
| Issue : 2 | Page : 40-44
Goiter prevalence and current iodine deficiency status among school age children years after the universal salt iodization in Jamnagar district, India
Naresh R Makwana, Viral R Shah, Sumit Unadkat, Harsh D Shah, Sudha Yadav
Department of Community Medicine (PSM), MP Shah Medical College, Jam Nagar, Gujarat, India
|Date of Web Publication||12-May-2012|
Harsh D Shah
Near Mahila Mandir, Kothariwada, Modasa- 383 315, Dist - Sabarkantha, Gujarat
Source of Support: None, Conflict of Interest: None
Introduction: Iodine is an essential micronutrient with an RDA of 100-150 μg for normal human growth and mental development. Iodine deficiency disorder (IDD) refers to complex clinical and subclinical disorder caused mainly due to inadequate intake of food with sufficient iodine . Aims and Objectives: The objective was to find out the prevalence of goiter in primary school children; to determine median urinary iodine concentration; to assess the level of iodine in salt samples at household. Materials and Methods: A 30-cluster survey was done in Jamnagar district in primary school children (6-12 years). A total of 70 children from first to seventh standards (35 boys and 35 girls) and 20 children from the community in each cluster were included. Total 2792 children were taken for the total goiter examination by population proportion to size in each cluster with informed consent. A total of 360 children were tested for the median urinary concentration and 750 salt samples were tested on the spot with a test kit from the households of the study population. Results: The total goiter rate was 4.83% among primary school children aged 6-12 years with no significant difference between age and sex. As the age increased the goiter prevalence also increased but the difference was not statistically significant (P > 0.05). The median urinary iodine excretion level of the district was found 80 mcg/l. It was observed that 81.9% salt samples had more than 15 ppm (as recommended) iodine content. Conclusion: The goiter prevalence is less in the study district but low median urinary iodine excretion and use of insufficient iodized salt at households describe the inadequacy in efforts to eliminate IDDs in the district.
Keywords: Goiter, iodine deficiency disorders, iodized salt, school age children
|How to cite this article:|
Makwana NR, Shah VR, Unadkat S, Shah HD, Yadav S. Goiter prevalence and current iodine deficiency status among school age children years after the universal salt iodization in Jamnagar district, India. Thyroid Res Pract 2012;9:40-4
|How to cite this URL:|
Makwana NR, Shah VR, Unadkat S, Shah HD, Yadav S. Goiter prevalence and current iodine deficiency status among school age children years after the universal salt iodization in Jamnagar district, India. Thyroid Res Pract [serial online] 2012 [cited 2017 Mar 22];9:40-4. Available from: http://www.thetrp.net/text.asp?2012/9/2/40/96030
| Introduction|| |
Iodine deficiency disorders (IDD), a preventable health problem, has been recognized in India since years. Unlike other micronutrients deficiency, iodine deficiency disorders are due to an inadequate amount of iodine in water, soil, and foodstuffs. This health problem affects all age groups of the population living in the same geographic areas without depending on their socioeconomical status. People living in areas affected by severe iodine deficiency may have an intelligence quotient (IQ) of up to 13.5 points below that of those from comparable communities in areas where there is no iodine deficiency. This subtle degree of mental deficiency causes an immediate effect on the child's school performance, intellectual ability, and working capacity and thus, the quality of life in communities and economic productivity. ,
It is estimated that about 167 million people are "at risk" of IDD, about 54.4 million people have a goiter, and more than 8.8 million people have IDD-related mental/motor handicaps.  The surveys conducted by Central and State health Directors, ICMR, and Medical institutes have clearly demonstrated that not even a single state/UT is free from IDDs and overall 82% are endemic districts in the country. In Gujarat, 50% districts were endemics with prevalence of more than 10% of the total goiter rate. 
Fortification of salt with iodine is the widely accepted preventive strategy to fight against IDD. Several studies carried out in India have shown a high percentage of goiter incidence. ,, In 1983, mandatory iodization of all table salt was introduced in India in an attempt to eliminate iodine deficiency. The Government of India has relaunched National Iodine Deficiency Disorders Control Programme (NIDDCP) in the year 1992 with a goal to reduce the prevalence of IDD to nonendemic level. After implementation of NIDDCP, India has made considerable progress toward IDD elimination.  During November, 2005, central government has issued notification banning the sale of noniodized salt for direct human consumption in the entire country, which was effective from 17 th May, 2006 under the Food Adulteration Act.  In 2009, the survey was carried out in Jamnagar district with the aims to determine the prevalence of goiter in primary school children aged 6-12 years; to determine median urinary iodine concentration (UIC); and to assess the level of iodine in salt samples at households of the surveyed population.
| Materials and Methods|| |
Selection of the study population, sample size, and sampling method
The 30-cluster cross-sectional study was conducted in the entire 10 Talukas of Jamnagar district in 2009. The list of villages, primary schools, and population were obtained from the Jilla Panchayat of Jamnagar. Before starting the survey, consent from the institution, chief district health officer, Jamnagar, and district education officer, Jamnagar, were taken. Total 30 villages were selected from the Jamnagar district by using the cluster sampling technique. Census 2001 population was used for sampling. Areas mentioned as urban areas like cities, towns, talukas headquarters were excluded from the village list to focus only the rural population of Jamnagar district. The survey was done among these villages in children studying in primary schools from first to seventh standards in the age group of 6-12 years. Total 70 children (35 boys and 35 girls) were examined from each primary school of selected villages for goiter. About 30% school dropout rate and absenteeism was considered, 20 students (10 boys and 10 girls) were examined in the community for iodine deficiency on the same day in the same village. Cases of goiter were identified and the following classification was used for goiter: (a) grade 0 - not visible, not palpable, (b) grade 1 - palpable, but not visible, and (c) grade 2 - palpable and visible, as per the WHO/UNICEF/ICCIDD guidelines. 
At the end of the survey total 2792 children were examined against 2700 minimum estimated sample size for the total goiter rate from the 30 clusters of the villages.
A total of six samples from schools and six from the community were selected using a simple random-sampling technique for taking the urine sample. So, in each cluster 12 urine samples were collected including 6 samples from boys and 6 from girls. In 30 clusters, total 360 urine samples were collected (0.5-1.0 ml) and tested for urinary iodine excretion. Plastic bottles with screw caps were used to collect the urine samples, which were stored in a cool dry place and sent to state IDD laboratory for testing by expert technician. Few drops of toluene were added to each urine sample to inhibit bacterial growth and to minimize bad odor. Child no., cluster no., and date of urine collection were mentioned on every bottle of urine sample to identify it. The ammonium persulfate titration method was used to detect the urinary iodine excretion level. The method is based on following principle: urinary iodine is released after the digestion of urine with ammonium persulfate. The released iodine catalyzes the reduction of ceric ammonium sulfate (yellow) to cerous form (colorless) (Sandell-Kolthoff reaction).  The color disappearance is measured by a spectrophotometer in the form of optical density (OD), which is then measured by constructing a standard curve on the graph paper by plotting iodine concentration in μg/l.
During the survey, 25 salt samples were tested using the simple random-sampling technique through household visits from the surveyed children: 12 from the schools and 13 from the community children in each 30 clusters to know the level of iodization of salt. Therefore, total 750 salt samples were tested. These samples were tested qualitatively on the spot with a MIB kit provided by UNICEF and iodine concentration was recorded as 0, < 15 and >15 ppm. ,
All the data were entered in MS excel 2007 and analyzed by using Epi Info software, version 3.5.1. The Chi-square test was applied where it was needed. P values were kept significant at the level 0.05.
| Result|| |
In the present study, a total of 2792 children were studied from 6 years to 12 years of age group of whom 50.5% were males and 49.5% were females. The detailed age and sexwise distribution of children is shown in [Table 1]. The overall prevalence of goiter among the study population was found 4.83%. [Table 1] showed that the increase in prevalence was consistent with increase in age of the studied children. In the age group of 12 years children, the prevalence of goiter was found significantly higher with males and female difference. The overall prevalence of goiter was higher in females 5.1% compared to males 4.6%. The difference of prevalence between sexes was not statistically significant. (χ2 = 0.223, degree of freedom = 1, P value = 0.63).
[Table 2] shows the geographical difference between talukas regarding the prevalence of total goiter. During the survey, it was found that a mild prevalence was seen in 50% of study areas. Out of studied 10 talukas, 5 talukas had a prevalence of mild severity which was more than 5% but less than 19.9%.
During the study, median urinary excretion among the studied children was 80 μg/l from total collected urine samples (n = 360). From the studied talukas, 60% (6) talukas had median urinary excretion less than 100 μg/l within the range of 50-99.9 μg/l [Table 3].
|Table 1: Age and sex-wise distribution of grade of goiter of the study district|
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|Table 2: Taluka-wise distribution of grades of goiter of the study district|
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|Table 3: Distribution of participants according to median urinary iodine excretion of the study district (n=360)|
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On examining salt for iodization, it was observed that 81.9% (614) salt samples had more than 15 ppm iodine content, 8.5% (64) samples contained less than 15 ppm salt, and 9.6% (72) samples were not iodized [Table 4]. On exploring the iodine content of the studied talukas, it was observed that in four talukas (Jodia, Kalawad, Khambhalia, and Lalpur) more than 95% of samples contained more than 15 ppm iodine. In the present study, three talukas were observed of not using noniodized salt (Lalpur, Jodiya, Dhrol).
|Table 4: Taluka-wise distribution of iodization of salt of the study district (n =750)|
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| Discussion|| |
Iodine deficiency disorders (IDD) are preventable disorders, but in India previous studies had shown that no states or union territories of the country were free from IDD. , To assess the severity of the iodine deficiency of any area, WHO/UNICEF/ICCIDD had established the criteria on the basis of total goiter prevalence (palpable and visible goiter).  An area is classified as endemic for iodine deficiency when it has a total goiter prevalence rate of more than 5% among school children aged 6-12 years.  In the present study, it was found that the total goiter prevalence was 4.83% among school children aged 6-12 years. The sex difference had no impact on the prevalence of goiter as it was 5.1% and 4.6% in males and females respectively, (P = 0.63). Also, there was no impact of the age difference on the prevalence of goiter, (P = 0.066). This study revealed that the distribution of the prevalence of goiter was different within the district itself. Out of 10 talukas, half of the talukas had a goiter prevalence of more than 5%, though no talukas were found to have a severe and moderate degree of iodine deficiency disorders.
The goal of NIDDCP is to reduce the prevalence of iodine deficiency disorders below 10% by 2012.  In the previous studies conducted in Saurashtra regions, the goiter prevalences were reported 20.5%, 11.06%, and 25.2% in different districts. ,, Compared to these studies, the Jamnagar district had a low prevalence which was 4.83%.
Iodine is an essential micronutrient which has a daily requirement of 100-150 μg for normal growth and development. As per the national guidelines,  severity of IDD to be a public health problem was classified in three categories including (1) <20 μg/l - severe, (2) 20-49.9 μg/l - moderate, and (3) 50-99.9 μg/l - mild. A value of 100 μg/l or above is considered as normal. The median urinary iodine excretion level 100 μg/l and above was found in almost 40% talukas but the median urinary iodine level was 80 μg/l of all talukas in the current study. These findings indicated that the populations of 6 out of 10 studied talukas were having biochemical deficiency of iodine. They also indicated it as continued but inadequate efforts of ensuring a supply of iodized salt to the population. Different median urinary iodine levels were reported by different authors indicating deficiency or no deficiency of iodine in respective populations in their areas. ,,, A recent study by U. Kapil et al. had shown that 86% districts of India had a urinary iodine level more than 100 μg/l.  The current study also identified that within the district median urinary excretion level may vary.
In India, IDD can be eliminated by changing dietary habits or eating certain kinds of the foods grown in that area. The preventable measures can also be taken by fortification of salt with iodine which has been low cost and successful intervention throughout the world. In the present study, a larger population was found using the iodized salt more than 15 ppm. But 8% of the studied population was using salt less than 15 ppm of iodine and 9.6% population was not using iodized salt at all. In NFHS-3, it showed that 51% population of the country was using adequate iodized salt (>15 ppm) and 24% were using noniodized salt.  The goal of USI is to cover more than 90% of household to consume iodized salt.  The current study revealed that four talukas of the district had adequate consumption (more than 95%) of iodized salt (> 15 ppm) and also, three talukas were free from the use of noniodized salt which showed the success of the NIDDC program within the district. To maintain the efforts of elimination within the district, the focus on universal salt iodization should be kept on the population-based data rather than geographical. In the present study, data revealed that population was using noniodized salt (9.6%) and iodized salt less than 15 ppm (8%) could be the future threat to reach the goal of decreasing the prevalence of goiter less than 10%.
The findings of the present study suggest that the Jamnagar district is in the transition phase from iodine deficient to iodine sufficient with nearly mild goiter prevalence. But detailed data analysis should be done to identify geographical distribution of goiter prevalence within the district. Low median urinary iodine excretion and use of insufficient iodized salt described the present status of iodine deficiency of the district. These data should be taken into consideration to enhance the National Iodine Deficiency Disorder Program which needs sustained monitoring and intensified IEC activities to eliminate IDD in near future.
| Acknowledgments|| |
Authors are thankful to Government of Gujarat for providing financial assistance, CDHO Jamnagar, and District Education department for providing technical support
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[Table 1], [Table 2], [Table 3], [Table 4]