title: Urinary iodine excretion and thyroid function status in school age children of hilly and plain regions of Eastern Nepal.
abstract: BACKGROUND
  Iodine deficiency is a major public health problem in many developing countries including Nepal. The present study was designed to investigate the urinary iodine excretion (UIE), thyroid function status and household salt iodine content (SIC) in school-aged children (SAC) and to establish the relationships between these factors.
  
  
  METHODS
  A community-based cross sectional study was conducted in selected schools of two districts, Tehrathum and Morang, lying in the hill and plain region of eastern Nepal respectively. A total of 640 SAC, (Tehrathum n = 274 and Morang n = 366) aged 6-11 years, were assessed for UIE and household SIC. Among the 640 children, 155 consented to blood samples (Tehrathum n = 78 and Morang n = 77) to test for serum thyroglobulin (Tg), thyroid stimulating hormone (TSH), free triiodothyronine (fT3) and free thyroxine (fT4). UIE was measured by ammonium persulfate digestion method. SIC was measured by iodometric titration method and Tg, TSH, fT4 and fT3 were measured by immunoassay based kit method.
  
  
  RESULTS
  In Tehrathum and Morang, 9.5 and 7.7% of SAC had UIE values of UIE <100 µg/L while 59.5 and 41% had iodine nutrition values of >299 µg/L, with median UIE of 345.65 and 270.36 µg/L respectively. The overall medians were as follows, Tg 14.29 µg/L, fT3 3.94 pmol/L, fT4 16.25 pmol/L and TSH 3.61 mIU/L. There was a negative correlation between UIE and Tg (r = -0.236, p = 0.003) and a positive correlation between UIE and SIC (r = 0.349, p < 0.0001). We found 19.5%, n = 15 and 16.7%, n = 13 subclinical hypothyroid cases in Morang and Tehrathum respectively. Iodometric titration showed only 6.4% (n = 41) of the samples had household SIC <15 ppm. Multivariate analysis revealed that use of packaged salt by SAC of Tehrathum district correlated with higher UIE values.
  
  
  CONCLUSIONS
  Our focused data suggests that collaborative universal salt iodization (USI) programs are improving the health of children in the Tehrathum and Morang districts of Nepal. We also found that excessive iodine in a large portion of the study groups is a substantial concern and iodine intervention programs need to deal with both deficient and excessive iodine scenarios that can both be present simultaneously in study populations.
authors: Department of Biochemistry, School of Medicine, Patan Academy of Health Sciences, Lagankhel-5, PO Box: 26500, Lalitpur, Nepal. premshakya@pahs.edu.np.
authors: Prem Raj
authors: PR
authors: Shakya
authors: Department of Biochemistry, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. gelalbasanta@gmail.com.
authors: Basanta
authors: B
authors: Gelal
authors: Department of Biochemistry, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. binodkumarlaldas2000@yahoo.co.in.
authors: Binod Kumar
authors: BK
authors: Lal Das
authors: Department of Biochemistry, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. madhablamsal@yahoo.co.uk.
authors: Madhab
authors: M
authors: Lamsal
authors: Department of Community Medicine, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. maniparash@gmail.com.
authors: Paras Kumar
authors: PK
authors: Pokharel
authors: Department of Biochemistry, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. nepalashwini@gmail.com.
authors: Ashwini Kumar
authors: AK
authors: Nepal
authors: Department of Biochemistry, Faculty of Society and Health, Bucks New University, High Wycombe, Buckinghamshire, UK. profbrodie@hotmail.co.uk.
authors: David A
authors: DA
authors: Brodie
authors: Department of Paediatrics and Adolescent Medicine, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. gaurishankarshah@live.com.
authors: Gauri Shankar
authors: GS
authors: Sah
authors: Department of Biochemistry, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. nirmalbaral@hotmail.com.
authors: Nirmal
authors: N
authors: Baral
mesh_terms: D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007455:Iodine / Q000652:urine*; D008297:Male; D009390:Nepal; D013954:Thyroglobulin / Q000097:blood; D013961:Thyroid Gland / Q000502:physiology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013954:Thyroglobulin; D007455:Iodine; D013974:Thyroxine