Iodine deficiency disorder
(IDD) has been recognized as a major public health problem in India. Out
of 587 districts in the country, 282 have been surveyed for IDD and 241
have been found to be goiter-endemic [1]. In 1983-84, the Government of
India adopted a policy to achieve universal iodization of edible salt by
1992 [2]. District Kullu in Himachal Pradesh is a known iodine
deficiency endemic area. An earlier survey conducted in 2003 found
prevalence rate of TGR as 9.6% [3]. This study was conducted in 2012
with the objective to assess the current status of IDD amongst school
age children (6-12 years) in the district. Informed consent was taken
from each child and his/her parent. The project was approved by ethical
committee of All India Institute of Medical Sciences, New Delhi.
The 30 clusters (schools) were selected by using
Population Proportionate to Size (PPS) sampling methodology [4]. In each
school all children were enlisted and using random number table, 66
children were selected. The clinical examination of the thyroid gland
was conducted [4]. "On the spot" urine samples were collected randomly
selected 18 children. A total of 532 urine samples were collected and
tested. The UIE levels were analyzed using the wet digestion method [5].
From each cluster, 23 salt samples were collected (total of 681) and
tested by standard Iodometric Titration (IT) method [6]. The girls in
the age group of 11+ who had menstruation on the day of the survey [n=16],
did not consented and hence were excluded from the study. With
anticipated prevalence of iodine deficiency as 15%, absolute precision
of ±2.0, confidence level 95% and a design effect of 1.5, a sample size
of 1837 children was calculated.
A total of 1986 children were included. The TGR
prevalence was found to be 23.4% (Grade I- 23.1% and Grade II- 0.3%),
indicating moderate iodine deficiency. The UIE analysis (n=532)
revealed that the proportion of children with UIE level of <20, 20-49,
50-99, 100-199 and >200 µg/l, was nil, 6.0%, 19.3%, 30.5% and 44.2%,
respectively. The median UIE level was 175µg/L indicating no biochemical
deficiency of iodine in the population studied. Analysis of the salt
samples (n=681) revealed that 2.2%, 46.5% and 51.3% of salt
samples had <5ppm, 5-<15 ppm and 15ppm and more, iodine content,
respectively. Earlier studies conducted in district Kullu have
also documented the median UIE levels of 205µg/L (2003) and 200 µg/L
(2005), respectively in SAC [7-8].
Findings of the present study indicate that the
population studied is going through a transition stage from iodine
deficient to iodine sufficient. Earlier studies have also documented
similar finding of persistence of higher TGR for few years after
correction of iodine intake by the population [9-10]. The possibility of
goitrogenic factors leading to high TGR rate cannot be ruled out. There
is a need of enforcing the Prevention of Food and Adulteration Act, to
ensure that salt with iodine content of 15ppm and more, is sold in the
market.
Contributors: All the authors have contributed,
designed and approved the study.
Funding: DBT Government of India; Competing
interests: None stated.
References
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Accessed April 2, 2013.
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