Correlation between urinary iodine level and thyroid disease

Abstract

Objective To investigate the relationship between urinary iodine level and thyroid disease.Methods The study used a case-control design.One hundred and nine patients with thyroid disease from the Affiliated Hospital of Shanxi Institute for Endemic Disease Control were selected as case group from 2011 to 2012,and these patients were divided into three groups:Graves's disease (GD) group (n =48),chronic lymphocytic thyroiditis (HT) group(n =34) and thyroid nodules group(n =27).Sixty-two healthy people from the same region were selected as a control group.Urinary iodine was determined using arsenic cerium catalytic spectrophotometry,thyroid autoantibody (TRAb) and thyroid peroxidase antibody (TPOAb) was detected using electrochemiluminescence,while iodine absorption rate was measured using thyroid function analyzer,and thyroid volume was measured using type-B ultrasonic method.The relationship between urinary iodine level and patients with thyroid disease was compared with that of control group.Results Urinary iodine levels of patients with GD,HT,thyroid nodules and control groups were 313.95,375.20,220.20 and 196.50 μg/L,respectively.Urinary iodine levels of patients with GD and HT groups were higher than that of control group(Z =3.238,4.275,all P ＜ 0.0125).Urinary iodine level of patients with HT was higher than that of thyroid nodules(Z =3.762,P ＜ 0.0125).Iodine uptakes of GD,HT,thyroid nodules and control groups were (84.20 ± 16.90)％,(23.51 ± 6.72)％,(28.34 ± 8.02)％ and (29.31 ± 8.41)％; TRAbs of patients with GD,HT,thyroid nodules and control groups were (58.57 ± 20.31)％,(2.54± 1.00)％,(2.98 ± 0.83)％ and (3.01 ± 1.21)％; TPOAbs of patients with GD,HT,thyroid nodules and control groups were (117.03 ± 57.21)％,(251.00 ± 98.20)％,(16.81 ± 9.87)％ and (15.00 ± 7.23)％.Iodine uptake,TRAb and TPOAb of GD group were higher than those of control group(P ＜ 0.05).TPOAb of HT group was higher than that of control group(P ＜ 0.05).Urinary iodine levels of GD group and HT group were positively correlated with TPOAb(correlation coefficient were 0.462,0.478 all P ＜ 0.05).Conclusions Excessive iodine intake is found in patients with GD and HT.Determination of urinary iodine is helpful for individualized iodine supplementation. Key words: Urine; Iodine; Graves' disease ; Chronic lymphocytic thyriuditis