Thyroid dysfunction in region of excess iodine intake of Eastern Nepal


  • Saroj Thapa Department of Biochemistry, Kathmandu University School of Medical Sciences, Dhulikhel, Lalitpur
  • Madhab Lamsal Department of Biochemistry, BP Koirala Institute of Health sciences, Dharan, Lalitpur
  • Rajendra K. Chaudhari Department of Biochemistry, BP Koirala Institute of Health sciences, Dharan, Lalitpur
  • Basanta Gelal Department of Biochemistry, BP Koirala Institute of Health sciences, Dharan, Lalitpur
  • Saroj Kunwar Department of Biochemistry, Modern Technical College, Lalitpur
  • Nirmal Baral Department of Biochemistry, BP Koirala Institute of Health sciences, Dharan, Lalitpur



Excess iodine, Subclinical hypothyroidism, School children


Background: Iodine deficiency as well as iodine excess can result in an increased prevalence of thyroid disorders. The prevalence of excess iodine nutrition is increasing all over the world. The aim of the present study was to find the occurrence of iodine nutrition status in primary school children of Eastern Nepal and find the prevalence of associated thyroid dysfunction among those with excess urinary iodine concentration.

Methods: A community based cross sectional study was conducted in Udayapur district which is located in Eastern part of Nepal. Primary school aged children (6 years to 12 years) were enrolled in this study from three schools. Blood and urine samples were collected and assayed for urinary iodine concentration (UIC), free thyroid hormones (fT3 and fT4), and thyroid stimulating hormone (TSH).  

Results: The median UIC was 232.27 µg/L. The iodine status showed that 15.5% (n=31) had low UIC, 21% (n=42) had above requirement and 36% (n=72) had excessive iodine nutrition status. The mean concentration of fT3 and fT4 was 2.87 pg/ml and 1.21 ng/dl respectively, while the median TSH concentration was 3.03 mIU/L. The prevalence of thyroid dysfunction was 10% (n=20) with subclinical hypothyroidism being the most common. Majority of participants with subclinical hypothyroidism had excess UIC.

Conclusions: Above requirement and excess iodine nutrition is more common in region where there is unregulated consumption and improper monitoring of iodized salt. Subclinical hypothyroidism is common in regions of excess iodine nutrition.


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