Indian Pediatrics 2000;37: 536-539
Iodine Deficiency Disorders in Bargarh District of Western Orissa
Iodine deficiency (ID) is one of the wide spread nutritional deficiencies prevalent in the developing world and it continues to be a significant public health problem(1). A spec-trum of disorders, besides goiter, collectively referred as iodine deficiency disorders (IDD) are caused by environmental iodine defi-ciency(2). While all age groups are affected by it, children in their growing period and women in their reproductive age are most vulnerable(3). The school children of iodine deficient areas were found to have 13 intelligent quotient points lower than their counter parts in iodine sufficient areas(4). The cumulative conse-quences of iodine deficient population spell diminished performance for the entire economy of the affected nations(5). Goitre survey and urinary iodine estimation of school children are recommended by WHO/UNICEF/ICCIDD as important parameters to assess the ID status and related control programs(6). The National Goiter Survey team of DGHS, India conducted two sample surveys in two districts of Orissa (Sundergarh in 1987 and Puri in 1989) and found both to be endemic with goiter prevalence 30% and 19%, respectively(7). No further baseline data on the prevalence of IDD in Orissa is available after 1989. A pilot survey conducted by us during 1995 in Bargarh district which is adjacent to Sundergarh district indicated a high average total goiter rate (TGR) of 18% (range 9.2% to 32%) among school-age children. Therefore a district level survey was conducted during 1996-99 in the same district to measure the IDD status using outcome indicators like TGR and urinary iodine excretion (UIE) levels among school-age children.
The study was conducted during 1996-1999 in Bargarh district, adopting probability proportionate to size (PPS) cluster sampling method. As recommended by WHO/UNICEF/ICCIDD 30 clusters were taken to ensure a valid prevalence estimate(6). All the Gram Panchayats (GP) of 12 blocks of Bargarh district including all the urban areas were enlisted with their population. Their cumulative population was calculated and 30 GP (clusters) were selected following recommended procedure. The primary schools located in the GP head quarter villages were selected for the study. A minimum of 80 children from each of these schools were included as per the estimation of sample size. The sample size was calculated with a relative precision of 10%, anticipated goiter prevalence of 32%, a design effect of 3 with a confidence interval of 95%. A total of 3088 children were examined since it became obligatory to examine all the students present on the day of survey due to demand from teachers and students. The goiter was graded as 0, I and II and TGR was calculated taking the sum of goiter grade I and II(6). Casual urine samples of 5-10 ml each from 414 (13.4%) of children were collected randomly in screw capped bottles with toluene and transported to the laboratory and stored at 4°C. The UIE estimation was done simul-taneously by using dry ash method as recommended by WHO/UNICEF/ICCIDD(8) and graded into normal (³100 mg/L), mild (50 to 99 mg/L), moderate (20 to 49 mg/L) and severe (<20 mg/L)(6). The test of hypothesis was carried out for two proportions by using Z-test to find out the significance difference between male and female.
Table I shows the sex distribution of school children with different grades of goiter. The TGR was found to be 10.8% and proportion of females having goiter was found to be more (12%) as compared to the males (9.7%) which is statistically significant. However, visible grade-II goiter was almost equal in both sexes. The TGR is defined as the total goiter rate (a sum of goiter grade I and II) per 100 subjects examined.
According to UIE level, 90.8% of children had deficient levels of iodine in their urine, of which 1.5%, 59.4% and 29.9% belonged to mild, moderate and severe states of IDD, respectively. Nearly 89.3% of urine samples had UIE level less than 50 mg/L indicating ID nutriture of the population studied.
Table I: Sex Distribution of the Children Showing Different Grades of Goiter
The prevalence of goiter in a population generally gives information about a region’s historical status with respect to ID. The present study revealed that the TGR among school children is 10.8%, which can be classified as mild prevalence of IDD. The prevalence among females was higher than the males, and majority of the goiter cases belonged to the grade I as observed in other studies(9,10).
Urinary iodine level is more objective and less prone to observational errors and indicates the recent intake of iodine. However, urinary iodine of an individual varies day by day, and gives information about the current status in a population. The estimation of UIE level showed 9.2%, 1.5%, 59.4% and 29.9% in normal, mild, moderate and severe grades of IDD, respectively. The median UIE of children was found to be 22.45 mg/L, indicating that more than 50% of them have moderate IDD. The proportion of the children having UIE levels <50 mg/L found to be 89.3%, whereas the recorded value for this group should not exceed 20% of the study population to indicate a state of elimination of IDD(6).
Kapil has reviewed the most recent data from five Indian states (Bihar, Kerala, Himachal Pradesh, Rajasthan and Uttar Pradesh) and three Union Territories (Delhi, Andaman and Nicobar and Pondicherry) where the cut-off value of median UIE was taken to be >100 mg/L as a criterion for assessing ID in a population. It was found that none of the states was deficient and 68 to 100% populations were consuming iodised salt(11). But in our study the median UIE value was found to be 22.45 mg/L, which is indicative of the moderate degree of IDD problem in this district. This value also correlates well with the findings of a KAP study conducted by us, which revealed that only 16.4% of people had been consuming iodised salt regularly.
However, the lacuna of iodine prophylaxis was conspicuous in this area as per our observation by the fact that the proportions of the local people using iodised salt regularly was very low. This again is observed due to lack of awareness among the public and poor avail-ability of iodised salt in this district (unpublished data).
In view of the above findings of this study, it may be recommended that the district may be urgently monitored for assessing the public access of iodised salt and public awareness about its regular use. This could be imple-mented by strengthening the Information, Education and Communication campaign, ensuring iodised salt availability and evaluating its benefit at regular intervals.
The authors are grateful to Dr. K. Satyanarayana, Director, for providing facilities and encouragement and Dr. H.B. Mohapatra, former Professor and Head, Department of Social and Preventive Medicine, S.C.B. Medical College, Cuttack for guidance. The cooperation of Dr. J.J.B. Geddam, S.C. Rout, T. Maharana, K. Dhal and H. Jena is sincerely acknowledged. Particularly thanked are the school teachers and the students of Bargargh district who contributed to the success of this study through their willing participation.
Contributors: SSSM coordinated the study, particularly its concept, design and interpretation and drafted the paper. GB measured the urinary iodine excretion and water iodine content. ASK carried out the clinical examination. Both GB and ASK helped in drafting the paper. NSM participated in data collection and ASA carried out statistical analyses.