Excessive iodine intake and ultrasonographic thyroid abnormalities in schoolchildren.
High nutritional levels of iodine may induce a higher prevalence of autoimmune thyroiditis, hypothyroidism, goiter, as well as hyperthyroidism, mostly in the elderly. This study assessed thyroid volume and ultrasonographic abnormalities as well as urinary iodine excretion (UIE) in 964 schoolchildren living in an iodine-sufficient area in southern Brazil. Thyroid volume correlated with age and body surface area in boys and girls. In 76.8% of the children, UIE was above 300 microg/l, with higher levels among boys compared to girls (484.2 microg/l vs 435.3 microg/l, p < 0.001). Thyroid abnormalities detected by ultrasonography included hemiagenesis (0.5%), nodules (0.2%), cysts (0.7%), and hypoechogenicity (11.7%). Goiter was present in 1.9% of the children. Hypoechogenicity, a relevant marker of autoimmune thyroiditis, was the most common abnormality found in our study, and this may be linked to excessive iodine intake.
Duarte
Glaucia C
GC
Thyroid Unit, Division of Endocrinology, Department of Clinical Medicine, University of São Paulo Medical School, Brazil. duarteglaucia@terra.com.br
Tomimori
Eduardo K
EK
de Camargo
Rosalinda Y A
RY
Catarino
Regina M
RM
Ferreira
Jerenice E
JE
Knobel
Meyer
M
Medeiros-Neto
Geraldo
G
D000293:Adolescent; D001830:Body Surface Area; D001938:Brazil / Q000453:epidemiology; D002648:Child; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage / Q000009:adverse effects* / Q000652:urine; D008297:Male; D013959:Thyroid Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000187:drug effects; D014463:Ultrasonography
D007455:Iodine