Sudha Rathna Prabhu1, Subramanian Kannan2, Shriraam Mahadevan3. 1. Department of Genetics, MEDISCAN, Chennai, Tamil Nadu, India. 2. Department of Endocrinology, Diabetology and Bariatric Medicine, Narayana Health City, Bengaluru, Karnataka, India. 3. Department of Endocrinology, Diabetes and Metabolism, Sri Ramachandra Medical College and Research Institute, Chennai, Tamil Nadu, India.
Sir,We read with interest the original article by Palaniappan et al. on iodine excess and Hashimoto's thyroiditis in children in which authors have reported a possible link between excess iodine intake by children and increasing the prevalence of autoimmune thyroiditis and eventually thyroid hypofunction.[1]In this regard, we would like to highlight recently published data on iodine status in several studies carried out in our country highlighting that iodine deficiency still continues to be endemic throughout India.[23] In the state of Tamil Nadu, the overall utility of iodine-rich salt among households and 6–12 years children has been extensively evaluated by Pandav et al. with estimations of urinary iodine excretion (UIE) and goiter indices, respectively. His study among school children aged between 6 and 12 years age has reported consumption of iodized salt at 18%, total goiter index of 13.5%, median UIE <100 mcg/L in 56%, and below 50 mcg/L in 22% of the children.[4]As most reference ranges of TSH, free T4 and UIE levels are strongly determined by diurnal and circadian variations, quality control standards for all biological samples in particular for UIE status become important. Several studies carried out in state of Tamil Nadu and Chhattisgarh have utilized stringent external and internal quality standards greatly adding to the quality of data presented.[5] By not including iodine deficient children and the prevalence of autoimmune thyroid disease in the iodine deficient cohort, it is difficult to accept a causal link between the iodine excess and autoimmune thyroid disease.We would also like to know about the laboratory details where the urine iodine was performed and standardization procedure undertaken in this aspect. The mean and standard deviation of the urine iodine excretion between the two groups are presented with a P value, but the confidence intervals of UIE between the two groups could better highlight the overlap.
Authors: Chandrakant S Pandav; Kapil Yadav; Rahul Srivastava; Rijuta Pandav; M G Karmarkar Journal: Indian J Med Res Date: 2013-09 Impact factor: 2.375