Iodine deficiency disorders (IDDs) are recognized as
a global public health problem in developing mountainous countries like
Nepal [1,2]. In 2007, a nationwide survey, showed that 9.5% and 17.9% of
school age children had urinary iodine excretion (UIE) less than 100µg/L
in the Eastern plains and hills, respectively [3]. Iodine deficiency
affects human growth and development including fetus, neonate, children
and adult population [4]. The final objective to correct iodine
deficiency is not only to increase the population access to iodized salt
but to normalize thyroid function tests [5]. The prevalence of
subclinical hypothyroidism in Eastern Nepal in a hospital based study
was 20.4% [6]. This study was undertaken to find out the iodine
nutrition and thyroid function status and among school age children of
Sunsari and Dhankuta districts.
Children 6-12 years age were recruited from the
selected four schools of two districts of Eastern Nepal. A total of 386
urine and 142 venous blood samples were randomly collected from the 772
children after written consent of the school authority and/or parents.
UIE was estimated by ammonium persulphate digestion microplate (APDM)
method using Sandell-Kolthoff’s reaction to find out the iodine status
of the children [7]. Blood samples were analyzed for thyroid function
test based on the enzyme linked immunosorbent assay (ELISA) by using
commercial kits from Human, Germany.
Table I shows the Iodine status of the study
children. Median UIE of Dhankuta was found to be lower (238.00 µg/L)
than that of Sunsari (294.96 µg/L) which indicate adequate iodine
nutrition at population level. Crystalline salt consumption was
significantly more in Dhankuta than in Sunsari (P<0.001). The
proportion of iodine deficient subject in Dhankuta and Sunsari were
25.3% and 14.1%, respectively.
TABLE I Demographic Characteristics and Iodine Status of Primary School Age Children of Dhankuta and Sunsari Districts
District |
Median |
M/F |
Iodine status, n (%) |
|
UIE* |
|
Severe
|
Moderate |
Mild
|
Optimum
|
More than |
Excess
|
|
(µg/L) |
|
iodine
|
iodine
|
iodine |
(100-199
|
adequate
|
(>300 |
|
|
|
deficiency |
deficiency
|
deficiency |
µg/L) |
(200-299
|
µg/L) |
|
|
|
(<20 µg/L) |
(20-49 µg/L) |
(50-99 µg/L) |
|
µg/L) |
|
Dhankuta (n = 194)
|
238.0 |
97/97 |
13(6.7) |
6(3.1) |
30(15.5) |
36 (18.6) |
30(15.5) |
79(40.7) |
Sunsari (n= 192) |
295.0 |
96/96 |
9(4.7) |
3(1.6) |
15(7.8) |
42(21.9) |
28(14.6) |
95(49.5) |
*P=0.07, M/F=Male/Female. |
There was a weak negative correlation between TSH and
UIE (r= -054, P=0.30), with positive correlations between UIE and
fT
Acknowledgement: Mother and Child Foundation, UK;
and Rotary International USA.
Funding: Mother and Child Foundation, United
Kingdom; Competing interest: None stated.
References
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