Subclinical hypothyroidism in obese children: an indicator of iodine deficiency
Elevated TSH in children is an indicator of iodine deficiency, which remains a huge problem world-wide, including the industrialised countries such as the UK and Australia. A survey of the UK iodine status in 2009 found that the median urinary iodine (UI) excretion in a sample of 737 schoolgirls was 80 mcg/l, and that more than two-thirds had UI of less than 100 mcg/l (the cut-off point for the diagnosis of iodine deficiency).
Iodine deficiency in children is associated with impaired mental function and retarded physical development, and even mild iodine deficiency is thought to lead to reductions of 10-15 in IQ points.
All children with elevated TSH should be tested for iodine deficiency and receive iodine supplementation if indicated. UI concentration is a good marker of the recent intake of iodine over days, and is the index of choice for evaluating iodine deficiency (spot urine concentrations have been shown to correlate well with 24-hour urine samples for iodine content measurements) .The clear benefits of correcting iodine deficiency in children (and indeed adults) far outweigh any potential risks.
Competing interests: No competing interests