Adult ; Case-Control Studies ; China ; epidemiology ; Female ; Humans ; Iodine ; urine ; Male ; Middle Aged ; Thyroid Diseases ; epidemiology ; urine

This study was conducted to examine the usual iodine intake in patients with thyroid diseases and to compare iodine status with normal subjects. The dietary iodine intake was assessed using a semi-quantitative food frequency questionnaire, and urinary iodine excretion was measured in 184 patients diagnosed with thyroid diseases and 207 normal subjects. The average usual iodine intake of patients with thyroid diseases was 673.8 +/- 794.9 ug/day and that of normal subjects was 468.9 +/- 481.9 ug/day. Among the patients with thyroid diseases, higher values were found in the patients with thyroid cancer (1460.6 +/- 1044.8 ug/day) and lower values were found in patients with simple goiter (443.5 +/- 470.4 ug/day). The urinary iodine excretions of patients and normal subjects were 4.33 +/- 5.70 mg/L and 2.11 +/- 0.69 mg/L, respectively. The iodine intake and urinary iodine excretion of patients with thyroid diseases were significantly higher than those of normal subjects (p < 0.05). The dietary iodine intake and urinary excretion of patients with thyroid cancer were significantly higher than other patients with thyroid diseases and normal subjects because of the use of seaweed or seaweed-containing dietary supplements (p < 0.01). This study suggests that the habitual ingestion of seaweed-containing dietary supplements in addition to dietary iodine intake will have adverse effects due to its excessive iodine intake.
Adult ; Diet ; Dietary Supplements ; Female ; Human ; Iodine/urine* ; Iodine/administration & dosage* ; Male ; Middle Age ; Reference Values ; Seaweed ; Thyroid Diseases/urine*

Adult ; Child ; China ; epidemiology ; Female ; Humans ; Iodine ; deficiency ; urine ; Male ; Thyroid Diseases ; epidemiology ; etiology

OBJECTIVETo establish a method of ion chromatography for urine iodide determination and evaluate its application in epidemiological studies.

METHODSUrinary iodine was determined using ICS-2500 ion chromatography coupled with IonPac AS7 analytical column (4 mm x 250 mm), silver electrode and direct current amperometry for 467 elderly subjects (above 50 years) with their urinary Tsh and FT4 also determined. The history of thyroid diseases was examined among these subjects.

RESULTSThe peak area of the ion chromatography was linearly correlated with urinary iodine concentration, with the correlation coefficient of 0.9999. The detection limit of iodide was around 3.5 microg/L (S/N=3), with coefficients of variation ranging from 3.16% to 3.45% and mean recovery rate of 95%. The urinary iodine level in the 467 elderly subjects showed a positively skewed distribution with the median level of 224.7 microg/L.

CONCLUSIONIon chromatography for urinary iodine determination has excellent selectivity, sensitivity, reliability, accuracy and stability, and may ensure satisfactory effect for application in epidemiological studies.

China ; epidemiology ; Chromatography, Ion Exchange ; methods ; Female ; Humans ; Iodine ; urine ; Male ; Mass Screening ; Middle Aged ; Reproducibility of Results ; Thyroid Diseases ; diagnosis ; epidemiology ; prevention & control ; urine

Objective: To investigate the effects of high iodine intake on thyroid function in pregnant and lactating women. Methods: A cross sectional epidemiological study was conducted among 130 pregnant women and 220 lactating women aged 19-40 years in areas with high environment iodine level (>300 μg/L) or proper environment iodine level (50-100 μg/L) in Shanxi in 2014. The general information, urine samples and blood samples of the women surveyed and water samples were collected. The water and urine iodine levels were detected with arsenic and cerium catalysis spectrophotometric method, the blood TSH level was detected with electrochemiluminescence immunoassay, and thyroid stimulating hormone (FT(4)), antithyroid peroxidase autoantibody (TPOAb) and anti-thyroglobulin antibodies (TGAb) were detected with chemiluminescence immunoassay. Results: The median urine iodine levels of the four groups were 221.9, 282.5, 814.1 and 818.6 μg/L, respectively. The median serum FT(4) of lactating women in high iodine area and proper iodine area were 12.96 and 13.22 pmol/L, and the median serum TSH was 2.45 and 2.17 mIU/L, respectively. The median serum FT(4) of pregnant women in high iodine area and proper iodine area were 14.66 and 16.16 pmol/L, and the median serum TSH was 2.13 and 1.82 mIU/L, respectively. The serum FT(4) levels were lower and the abnormal rates of serum TSH were higher in lactating women than in pregnant women in both high iodine area and proper iodine area, the difference was statistically significant (FT(4): Z=-6.677, -4.041, P<0.01; TSH: Z=8.797, 8.910, P<0.01). In high iodine area, the abnormal rate of serum FT(4) in lactating women was higher than that in pregnant women, the difference was statistically significant (Z=7.338, P=0.007). The serum FT(4) level of lactating women in high iodine area was lower than that in proper iodine area, the difference was statistically significant (Z=-4.687, P=0.000). In high iodine area, the median serum FT(4) in early pregnancy, mid-pregnancy and late pregnancy was 16.26, 14.22 and 14.80 pmol/L, respectively, and the median serum TSH was 1.74, 1.91 and 2.38 mIU/L, respectively. In high iodine area, the serum FT(4) level in early pregnancy was higher than that in mid-pregnancy and late pregnancy, and the serum TSH level was lower than that in mid-pregnancy and late pregnancy, the difference was statistically significant (FT(4): Z=-2.174, -2.238, P<0.05; TSH: Z=-2.985, -1.978, P<0.05). There were no significant differences in the positive rates of serum thyroid autoantibodies among the four groups of women and women in different periods of pregnancy (P>0.05). The morbidity rates of subclinical hyperthyroidism in pregnant women and lactating women in high iodine area were obviously higher than those in proper iodine areas, the difference was statistically significant (χ(2)=5.363, 5.007, P<0.05). Conclusions: Excessive iodine intake might increase the risk of subclinical hypothyroidism in pregnant women and lactating women. It is suggested to strengthen the iodine nutrition and thyroid function monitoring in women, pregnant women and lactating women in areas with high environmental iodine.
Adult ; China/epidemiology* ; Cross-Sectional Studies ; Female ; Humans ; Hypothyroidism/epidemiology* ; Iodides/administration & dosage* ; Iodine/urine* ; Lactation ; Nutritional Status ; Pregnancy ; Prevalence ; Thyroid Diseases/epidemiology* ; Thyroid Function Tests ; Thyroid Gland/physiology* ; Young Adult

OBJECTIVETo investigate the prevalence of thyroid diseases in a community which did not use iodized salt.

METHODSThe survey was conducted in Panshan, Liaoning Province. 1 103 inhabitants aged 14 years or more attended the examinations, which included questionnaire, physical examination and serum analysis. Iodine in the urine and thyroid B ultrasound examination were also conducted.

RESULTSThe prevalence of overt hyperthyroidism and hypothyroidism was 16.3 per thousand and 2.7 per thousand, respectively. Subclinical hyperthyroidism and hypothyroidism were detected in 37.2 per thousand and 9.1 per thousand of the subjects, respectively. Serum autoantibodies to thyroid were detected in 10.9% of the entire population. The prevalence of goiter was 20.7% (diffuse goiter 16.8% and nodular goiter 3.9%).

CONCLUSIONIn the iodine deficient areas, perhaps autoimmununization is not only related to the development of goiter but is also the main cause of subclinical hyperthyroidism and hypothyroidism.

Adolescent ; Adult ; Aged ; Autoantibodies ; analysis ; China ; epidemiology ; Female ; Goiter ; epidemiology ; Health Surveys ; Humans ; Hyperthyroidism ; epidemiology ; Hypothyroidism ; epidemiology ; Iodine ; deficiency ; urine ; Male ; Middle Aged ; Prevalence ; Residence Characteristics ; Sodium Chloride, Dietary ; Thyroid Diseases ; epidemiology ; immunology ; metabolism ; Thyroid Nodule ; epidemiology