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Brief Reports Indian Pediatrics 1999;36: 1253-1256 |
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Current Status of Prevalence of Goiter and Iodine Content of Salt Consumed in District Solan, Himachal Pradesh |
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K.S. Sohal, T.D. Sharma, Umesh Kapil* and Monica Tandon* From the Directorate of Health Services, Government of
Himachal Pradesh, Himachal Pradesh, India and Department of Human Nutrition,* All India
Institute of Medical Sciences, Ansari Nagar, New Delhi 110 029, India. |
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Iodine deficiency damages human health in several ways, most importantly by interfering with normal development of the brain. Some of the consequences of iodine deficiency are not reversible once they occur, but all of them can be completely prevented by easily available techniques of iodine supplementation. Surveys conducted in 275 districts of 25 states and 4 union territories of India have identified 235 districts as endemic for IDD(1-3). The district Solan of Himachal Pradesh is a known iodine deficiency endemic area. A survey conducted in 1956 reported a goitre prevalence of 39.9% in the district(4). To ensure adequate availability and use of iodized salt, the state government issued a ban on the sale of non-iodized salt for human consumption in 1976(5). Under this ban notification, iodized salt should contain a minimum of 30 ppm iodine at the manufacturer's level and 15 ppm iodine at the consumer level. During 1993-96, a GOI-UNICEF project was implemented in which intensive efforts were undertaken by government to ensure that only iodized salt was available to the population(6). The present study was conducted in 1997 with the objective to assess the prevalence of goiter and to estimate the iodine content of salt consumed by the population in the district. Subjects and Methods The study was conducted in the district Solan, Himachal Pradesh. Children in the age group of 8-10 years were considered for the present study. School children in this age group are recommended for the assessment of IDD because of their combined high vulnerability to the disease (goiter), representativeness of their age group in community and easy accessibility(7). In district Solan, the school enrollment of primary classes was more than 90% and hence the school approach was adopted. The multistage cluster sampling method-ology was followed for selecting the study population. The district had a total population of 3,03,000. All the rural and urban units in the district with their respective populations were enlisted. The 30 clusters, i.e., population units/villages/urban wards to be surveyed were selected by using population proportionate to size sampling methodology. In each identified population unit (cluster), all the primary schools were enlisted and one school was selected randomly for the detailed survey. In the selected schools, 220 children were surveyed. If the sample could not be covered in the school, adjoining schools were included to complete the sample of the cluster. The school teachers and children were briefed about the activities to be undertaken during the survey. Subsequently, the children between 8-10 years of age were identified with the help of school records for inclusion in the study. An attempt was made to study an equal number of children (70-80) in the ages of 8, 9 and 10 years. Grading of goiter was done according to the criteria recommended by the joint WHO/UNICEF/ICCIDD recommen-dations. Inter-observer variation was controlled by initial training on goiter grades within the experts. On the spot urine samples were collected from 10.7% of the subjects. Urinary iodine excretion was determined by the wet digestion method(8). The results were expressed as mcg iodine/dl urine. In each cluster, about 10 salt samples were randomly collected from families of the school children who were included in the study. The iodine content of the salt was estimated by the standard iodometric titration method(9). The sample size of children to be surveyed was calculated with a presumption that the prevalence of goiter at the time of the survey was 15%. A Confidence level of 95%, relative precision of 10% and design effect of three was considered for calculation of sample size. Utilizing these parameters, a sample size of 6510 was obtained (217 children per cluster). Results A total of 6724 school children in the age group of 8-10 years were included in the study. Three thousand three hundred and seventy seven males and 3347 females were studied. The total goiter prevalence rate was found to be 11.3%. The prevalence of goiter in male and female children has been shown in Table I. No significant difference was found in goiter prevalence amongst the male and female children. Table I__Prevalence of Goiter (n=6724)
It was found that 21 (2.9%), 42 (5.85%) and 142 (19.7%) of the children had urinary iodine excretion (UIE) levels of < 2, 2-4.9, and 5-9.9 mcg/dl, respectively. Five hundred and fifteen children had UIE of 10 mcg/dl and above. The median urinary iodine excretion level was 15.0 mcg/dl. Salt with a 15 ppm iodine content was consumed by 91.0% of the subjects. Seven per cent of families consumed salt with an iodine content of less than 15 ppm and only 1.9% subjects consumed salt with nil iodine. Discussion It has been recommended that if more than 5% school age children (6-12 yrs) are suffering from goiter, the area should be classified as endemic to iodine deficiency(7). In the present study, a total goiter prevalence rate of 11.3% was found, signifying that in district Solan mild iodine deficiency existed. In earlier study in 1956, a goiter prevalence of 39.9% was reported in the district. The decreases in the prevalence of goiter could be possibly attributed to the availability of iodised salt to the beneficiaries. The WHO/UNICEF/ICCIDD have recom-mended that no iodine deficiency is indicated in a population when median urinary iodine excretion is 10 mcg/dl, i.e., more than 50% of the urine samples have UIE level of 10 mcg/dl, and not more than 20% of samples have UIE level of 5 mcg/dl(7). In the present study, the median urinary iodine excretion of the children studied was 15.0 mcg/dl and only 8.7% of children had UIE level of less than 5mcg/dl. These findings indicated that there was no biochemical deficiency of iodine in the subjects studied. In the pesent study, 98% of the beneficiaries consumed iodized salt. The adequate iodine nutriture could be possible due to recent efforts of ensuring availaibility of iodized salt to the population in the district. The prevalence of goiter indicates past iodine nutriture while urinary iodine excretion level indicates current iodine status in a population. In the present study, it was found that total goiter rate was 11.3% (indicating mild iodine deficiency) while median UIE was 15.0 mcg/dl (indicating no biochemical iodine deficiency in the population). Hence, the findings of the the present study suggested that the population of Solan district is in a transition phase from iodine deficient to iodine sufficient. This was reflected by the prevalence of the goiter of 11.3% in children between 8-10 years and median UIE of 15.0 mcg/dl. These findings indicated that elimination of IDD from the district Solan can be achieved by continued and sustained supply of the iodized salt with adequate quantity of iodine to the entire population. Acknowledgements The present research study was conducted as a part of implementation of GOI-UNICEF project to have baseline data on iodine deficiency in district Solan. Authors would like to thank Dr. Sheila Vir, Project Officer, UNICEF, India Country Office for the technical help extended during different stages of the survey. We would also like to thank school principals, teachers and students for their kind co-operation in the data collection. References 1. Hetzel BS. Iodine deficiency disorders (IDD) and their eradication. Lancet 1983; ii: 1126-1129. 2. Epidemiological survey of endemic goitre and endemic cretinism. An ICMR task force study. Indian Council of Medical Research, ICMR Press, New Delhi, 1989; pp 11-16. 3. Pandav CS, Kochupillai N. Endemic goiter in India: Prevalence, etiology, attendant disabilities and control measures. Indian J Pediatr 1982; 50: 259-271. 4. Pandav CS, Karmarkar MG, Nath LM. The National Goiter Control Programme. National Health Programme Series 5, Government of India Press, New Delhi, 1988; p 39. 5. Prakash R, Sunderesan S, Mohan R, Mukherjeee S, Vir S, Kapil U. Universalization of access to iodized salt _ A mid-decade goal. The Salt Department, Ministry of Industry, Government of India, Faridabad, Thompson Press (India) Ltd 1994; pp 2-6. 6. Kapil U, Sohal KS, Nayar D. Process of implementation of National Iodine Deficiency Disorders Control Programme activities in Himachal Pradesh, India. Indian J Pub Hlth 1995; 39: 172-175. 7. Report of a Joint WHO/UNICEF/ICCIDD Consultation on Indicators for Assessing IDD and their Control Programmes. World Health Organization, Geneva, 1993; pp 14-18. 8. Dunn JT, Crutchfield HE, Gutekunst R, Dunn D. Methods for Measuring Iodine in Urine. A Joint Publication of WHO/UNICEF/ICCIDD 1993; pp 18-23. 9. Sullivan KM, Houston R. Gorstein J, Cervinskas J. Monitoring Universal Salt Iodization Pro-grammes_UNICEF/ICCIDD/PAMM/WHO. PAMM/MI/ICCIDD Publication, Georgia, 1995; pp 86-90. |
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