A STUDY ON PREVALENCE OF IODINE DEFICIENCY DISORDERS AMONG SCHOOL CHILDREN OF DHARWAD DISTRICT.
BRIEF RESUME OF INTENDED WORK: Need for study:
Iodine is an essential element for thyroid function, necessary for the normal growth, development and functioning of the brain and body. While iodine deficiency is known to cause endemic goiter, its most deleterious effect may be on the developing brain of the fetus, ranging from mild brain dysfunction to irreversible intellectual impairment. It is the single most common cause of preventable mental retardation and brain damage in the world today1.
Iodine deficiency disorders (IDDs) is known to have a significant public health (PH) problem all over the world. About 1.5 billion people worldwide live at risk of IDD of which more than 655 million people are already affected with IDDs. In India, about 200 million people live at risk of IDDs, whereas more than 71 million people are suffering from goiter and other IDDs2.
Initially confined to hilly regions, new endemic areas of goitre are subsequently identified all over the country. As per the joint surveys conducted in the country by the Directorate General of Health Services, Indian Council of Medical Research, the State Health Directorates and Health Institutes it has been found that 263 districts of 324 districts surveyed in all the 28 States and 7 Union Territories are endemic (Prevalence of Iodine Deficiency Disorders more than 10%). No State/UT is free from Iodine Deficiency Disorders. In Karnataka 6 districts of the 20 districts surveyed are endemic for IDDs2.
Enlargement of thyroid gland is the common manifestation of IDD and goitre prevalence survey is used as a diagnostic tool for identifying areas of IDD. Failure to undertake early detection and intervention measures results in secondary disabling conditions. School-age children are highly vulnerable for IDD1, & can be the target group for early diagnosis & intervention.
Community based studies which will estimate the burden of IDDs will be very useful for developing intervention measures in iodine deficient areas. Hence a need was felt to undertake the study on prevalence of IDDs among school children in the age group of 6-12 years as no such similar study was done in Dharwad District.
Review of Literature:
As per surveys conducted in the country by the Directorate General of Health Services, Indian Council of Medical Research, the State Health Directorates and Health Institutes it has been found that 263 districts of 324 districts surveyed in all the 28 States and 7 Union Territories are endemic (Prevalence of Iodine Deficiency Disorders more than 10%). No State/UT is free from Iodine Deficiency Disorders. In Karnataka 6 districts of the 20 districts surveyed are endemic for IDDs2.
A study by R.S.P. Rao et al in rural field practice area of Department of Community Medicine, KMC, Manipal, found that over all prevalence of goitre was 30 %. Prevalence among males 28.8% and among females it was 31.2 %. In both sexes goitre rate increased with the advancement of age. Prevalence of grade I and grade II goitre was 29.4 %and 0.6% respectively.Prevalence of goitre was significantly higher among children who had urinary iodine excretion level less than optimum (<10mcg/dl). Estimation of iodine content in the salt sample revealed that 48.3 % of samples had adequate iodine content(>=15 ppm). There was significant increase in the goitre rate as the iodine content in the salt decreased (p=0.01)3 .
A study by R. Kamath et al, among school children in Belgaum District, found that overall prevalence of goitre was 16.7%. Prevalence of palpable goitre was 16.4 % and visible goitre was very low (0.3%). Higher prevalence was found among females (21.1%) when compared to that of male children (12.8 %).Prevalence of goitre increased significantly with advancement of age until 16 years. 72.1 % children were consuming rock salt and only 27.9 % were consuming powdered salt at their homes. Estimation of Iodine content in the salt samples showed that 68.7 % of the samples had inadequate iodine content. Prevalence of goitre was significantly high among children who consumed rock salt (16.2%) as compared to those who used powdered salt (11%)4.
A study by Imtiyaz A Bhat et al, in Jammu region, found an overall goiter prevalence of 11.98%. Females had a prevalence of 16.1% and males 10.1%. The median urinary iodine excretion in the region was 96.5 µg/l (range: 29.0-190.0 µg/l). Forty-nine percent of subjects had biochemical iodine deficiency with 6.7% having moderate and 42.53% mild iodine deficiency. 74.47% of households consume powdered salt with 98.17% powdered salt samples having an Iodine content of greater than 15 ppm 5.
A study by Dilip Kumar Das et al, in a district of West Bengal, India ,found Total Goitre Rate (TGR) 13.7% (95% CI = 12.3–15.1%). Grade 1 was 11.4% and Grade 2 (visible goitre) was 2.3%. The TGR was influenced by the age and sex factors but not by religion and residence. The median urinary iodine excretion level was 13 µg/dL (normal range: 10–20 µg/dL) and none had a value less than 5 µg/dL. There was significant negative correlation between UIE (Urinary Iodine Excretion) levels and the age and place of residence factors. Almost 80% of salt samples tested had adequate iodine content (≥ 15 ppm). Consumption of iodized salts was lower among Hindus and in rural area6.
A study by Syed N et al, in Bangladeshi Children, found that the euthyroid group had better scores in reading and spelling (P < 0.001) and mathematics (P < 0.01) compared with the hypothyroid group in study done on Bangladeshi children7.
Objectives of study: To study the prevalence of Iodine deficiency disorders among school children in Dharwad District.
To study salt consumption pattern among the school children.
To study clinical manifestation of Iodine deficiency among them.
To study psychosocial factors associated with Iodine deficiency disorders.
MATERIALS AND METHODS:
7.1 Source of data: School children in the age group of 6-12years in Dharwad district .
7.2 Methods of collection of data:
Type of study: Community based cross sectional study.
Duration of the study: One year from Janaury 2011 to December 2011
Sampling: Children in the age group of 6 – 12 years from schools of Dharwad district will be selected by Population Proportionate to Size (PPS) cluster sampling.
Sample size: Based on expected prevalence of 16.7%4 at 95% confidence interval and an allowable error of 10% , sample size works out as 1995. (Formula used N= 4PQ/L2 ) Subsample of this will be taken for urine and salt iodine analysis.
Inclusion criteria:School Children in the age group of 6-12 years.
Pre-tested and Semi structured proforma will be used to collect the information regarding demography factors, salt consumption, psychosocial factors of iodine deficiency.
Clinical examination to look for presence of goitre as per the WHO guidelines1.
Estimation of Urinary Iodine Excretion by the Wet Digestion Method (Sandell-Kolthoff)2. 10ml Casual urine sample will be taken. Collection, Dispatch and Analysis of Urine Samples will be as per revised policy guidelines on National Iodine Deficiency Disorders Control Programme October 2006.
Estimation of Iodine Content of Salt by Semi-quantitative test kit.
Permission will be obtained from the school authorities,written consent wiil be taken from parents.
Statistical Methods: Appropriate statistical tests like percentages, proportions, chi square test
7.3 Does the study require any investigations to be conducted on patients or animals? Specify.
Yes,urinary iodine estimation.
7.4 Has the ethical clearance been obtained from ethical committee of your Institution?
Yes, ethical clearance has been obtained from Ethical Committee of KIMS, HUBLI.
LIST OF REFERENCES WHO, UNICEFF, ICCIDD. Assessment of iodine deficiency disorders and monitoring their elimination. Third edition:1,36.
National Rural Health Mission IDD & Nutrition Cell ,Directorate General of Health Services, Ministry of Health & Family Welfare, Government of India New Delhi. Revised Policy Guidelines On National Iodine Deficiency Disorders Control Programme. 2006: October:1,25.
R.S.P. Rao, R. Kamath, Acharya Das, N.S. Nair, Keshavamurthy . Prevalence of Goitre Among School Children in Coastal Karnataka. Indian Joumal of Pediatrics. 2002: 69(6): 477-479.
R. Kamath, V. Bhat, R.S.P. Rao, D. Acharya, U. Kapil1, M.S. Kotian D.S.Nayak. Prevalence of Goitre Among School Children in Belgaum District. Indian Journal of Pediatrics. 2009: 76(8): 825-828.
Imtiyaz A Bhat1, Iqbal M Pandit1, S Mudassar. Study on prevalence of iodine deficiency disorder and salt consumption patterns in Jammu region. Indian journal of community medicine. 2008 : 33: 1: 11-14.
Dilip Kumar Das, MD, Indranil Chakraborty, MD, Akhil Bandhu Biswas, MD, Indranil Saha, MD, Piyeanku Mazumder, MD and Sankar Saha, DPH Goitre Prevalence, Urinary Iodine and Salt Iodisation Level in a District of West Bengal, India. Journal of the American College of Nutrition.2008: 27: 3: 401-405.
Syed N, Sally M. Grantham-McGregor3, Khan M. Rahman* and Andrew Tomkins. Biochemical Hypothyroidism Secondary to Iodine Deficiency Is Associated with Poor School Achievement and Cognition in Bangladeshi Children. Journal of Nutrition. 1999: 129: 980-987.
SIGNATURE OF THE CANDIDATE
REMARKS OF THE GUIDE
The study is focussed on public health problem and community based Research also supports UNICEF and Government of Karnataka efforts to reduce burden of IDD in Karnataka.