Abstract: ［Abstract］〓Objective〖HTSS〗〓To investigate the 25 hydroxyvitamin D status in children with Graves disease and the role of vitamin D in the pathogenesis of Graves disease.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓Thirtyseven children with Graves disease in Shijiazhuang Han nationality were selected. The patients were divided into summerautumn group(JuneNovember) and winterspring group(December to May of the following year) according to the time of their first visit, and < 10 years old group and ≥10 years old group according to the age. Four milliliters of fasting venous blood were collected to test thyrotropin, total thyroxin, free thyroxine,total triiodothyronine, free triiodothyronine, thyrotropin receptor antibody and thyroglobulin, thyroglobulin antibody, 25 hydroxyvitamin D level; The lengths, widths and thicknesses of the right and left lobes of the thyroid were measured by ultrasound and the volume of thyroid was calculated. The iodine uptake rate of 3, 6 and 24hour were measured by oral 131I method, and the iodine in the midstream urine was measured by electrochemical method.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓The level of 25 hydroxyvitamin D in 37 children with Graves disease was（49.95±22.82） nmol/L, 11 cases(29.73%)were deficient, 4 cases(10.81%) were insufficient  and 22 cases(59.46%) were sufficient. The levels of 25 hydroxyvitamin D in the summerautumn group was higher than the winterspring group(P＜005).The 25 hydroxyvitamin D level was no significant difference between <10 years old group and ≥10 years old(P＞005). There were no correlations between serum 25 hydroxyvitamin D level and thyroid volume,total thyroxin, free thyroxine, total triiodothyronine, free triiodothyronine, urine iodine, 131I iodine absorption rate at 3, 6 and 24hour(P＞0.05).
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓The serum level of 25 hydroxyvitamin D in children with Graves disease was not significantly decreased, and the seasonal changes were still present. The level of serum 25 hydroxyvitamin D does not affect the laboratory and clinical parameters of children with Graves disease.

Key words: Graves disease, 25hydroxyvitamin D, child