A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Winter, 2016 | Number 1, Volume 30

Iodine deficiency may be a factor in autism

Iodine deficiency may play a role in autism spectrum disorders (ASD), a new study suggests. 

Anna Blażewicz and colleagues tested the urinary iodine levels and thyroid hormone levels of 40 boys with ASD ranging in age from 2 to 17 years, comparing the children to 40 neurotypical boys. They also administered the Child Autism Rating Scale (CARS) to the children with ASD. 

The researchers report, “Nineteen out of 40 children with ASD had mild to moderate iodine deficiency.” Levels of iodine in the ASD group were significantly lower than levels in the control group. The thyroid hormone levels of children with ASD were within normal reference ranges, but when the researchers controlled for a number of variables they determined that children with autism had significantly lower levels of fT3 and fT4 and higher levels of TSH. 

The researchers say, “Concentration of iodine in urine was negatively associated with clinician’s general impression for children between 11 and 17 years. Emotional response, adaptation to environmental change, near receptor responsiveness [taste and smell] , verbal communication, activity level, and intellectual functioning are more associated with urinary iodine than other symptoms listed in CARS.” 

The researchers conclude, “The severity of certain symptoms in autism is associated with iodine status in maturing boys. Thyroid hormones were within normal reference ranges in both groups while urinary iodine was significantly lower in autistic boys suggesting that further studies into the nonhormonal role of iodine in autism are required.”


“Iodine in autism spectrum disorders,” Anna Blażewicz, Agata Makarewicz, Izabela Korona-Glowniak, Wojciech Dolliver, and Ryszard Kocjan, Journal of Trace Elements in Medicine and Biology, Vol. 34, March 2016, 32-37. Address: Anna Blażewicz, Medical University of Lublin, Chodźki 4A, 20-093 Lublin, Poland, [email protected].