Child ; China ; Humans ; Iodine ; urine ; Sodium Chloride, Dietary

A modified micromethod for measuring urine iodine was successfully established and validated. The micromethod showed good correlation with the method used by several World Health Organization (WHO) collaborative laboratories (y = 0.9342x + 4.6213; r = 0.962; p = 0.01; n = 50). The micromethod also showed good agreement when compared to the reference WHO method. The sensitivity of the assay was 13.809 ug/L (n = 8) and mean recoveries were 114, 103 and 106% at concentrations of 30, 40 and 50 ug/L (n = 3) respectively. At iodine concentrations of 51 +/- 15.5, 108 +/- 32.4 and 149 +/- 38.6 ug/L, intra-assay coefficient of variations (CVs) were 13%, 7% and 5% respectively (n = 20), and inter-assay CVs were 10%, 15% and 7% respectively (n = 10). The assay showed good linearity plot (y = 1.0407x + 60.451; r = 0.993; n = 3).
Lower case en ; assay ; Iodine ; ug/L ; In 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*

Korea is a region abundant in foods containing iodine such as seaweed and fish. An adequate amount of iodine consumption is extremely important as both a deficiency and excess of iodine can result in health problems. This study was undertaken to assess the iodine nutritional status of normal Korean adults who consume seaweed and fish, and to determine the relationship between the dietary iodine intake and the urinary excretion of iodine. The dietary assessment of iodine using a food frequency questionnaire and a urinary iodine excretion examination were carried out in 278 healthy adults. The iodide selective electrode (ISE) method was used to determine urinary iodine excretion. The average usual iodine intake of Korean adults was 479 micrograms per day (ranging from 61 micrograms to 4086 micrograms). There was no significant difference in sex or age. The major food sources of dietary iodine included seaweed (66%), milk and dairy products (11%), and fish (9%). The contribution of seaweed to the total iodine intake tended to increase with age while the contribution of milk decreased. The average urinary excretion of iodine was 674 micrograms/g creatinine and there was no significant difference in sex or age. The dietary iodine intake was positively correlated with the urinary excretion of iodine (gamma = 0.60, p < 0.01). The study data indicated that the iodine intake and excretion of Koreans depends mostly on the amount of seaweed consumption like sea tangle and sea mustard. As well, the current iodine intake and urinary iodine excretion by Koreans seems to be higher than in other countries.
Adult ; Dietary Supplements ; Female ; Human ; Iodine/urine* ; Iodine/administration & dosage* ; Korea ; Male

OBJECTIVETo analyze the feasibility of reducing the concentration of iodized salt based on the results of iodized salt monitoring from the year of 2004 to 2006.

METHODSSpecial software for iodized salt monitor and SAS 9.0 were used to analyze salt monitoring data and urine iodine data of women at reproductive age in high-risk areas in 2006.

RESULTSBased on the data from monitoring program, adequate iodized salt coverage increased constantly in China. The quality of iodized salt was stable with less than 2 mg/kg iodine loss at production level but most was at 3 mg/kg iodine loss under estimation during the process of distribution from factory to households. Individual daily intake of iodized salt was higher than the recommendation from WHO but the average level of urinary iodine excretion of women and school children was more than adequate.

CONCLUSIONTo decrease the concentration of iodine in edible salt was necessary in China. Our findings provided recommendation on the concentration of iodine in edible salt that should be adjusted from the current concentration of 35 mg/kg to 25-28 mg/kg, and the variation should be controlled from the current range of +/- 15 mg/kg to +/- 10 mg/kg.

Adolescent ; Adult ; China ; Female ; Humans ; Iodine ; urine ; Middle Aged ; Nutrition Assessment ; Nutrition Policy ; Sodium Chloride, Dietary ; urine ; Young Adult

BACKGROUND: Thyroid cancer patients should be on low-iodine diet (LID) before radioactive iodine therapy (RAIT) to maximize the effect of RAIT. Urinary iodine excretion is the most accurate marker of very recent dietary iodine intake. We developed and evaluated the analytical performance of inductively coupled plasma-mass spectrometry (ICP-MS) to determine urinary iodine concentration. METHODS: We evaluated the linearity, precision, accuracy, and lower limit of quantification (LLOQ) of an ICP-MS method (Agilent 7500ce) to determine urinary iodine concentration in accordance with the Food and Drug Administration (FDA) guidelines for bioanalytical method validation. This method was used to determine and compare the iodine concentration in random urine samples of 120 thyroid cancer patients on LID for 1 week and 80 healthy adults on normal diet. RESULTS: Our ICP-MS method showed good linearity (1.0-1,913 microgram/L; R2>0.999). Both intra-day and inter-day precision CV were within 20% for the LLOQ (1 microgram/L) and within 15% for the other concentrations. Accuracy was 110-120% for the LLOQ and 95-115% for the other concentrations. The median concentration of iodine in random urine samples from thyroid cancer patients on LID (38.7 microgram/L) was significantly lower than that of healthy subjects (238.8 microgram/L) (P<0.0001). CONCLUSIONS: Urinary iodine analysis by ICP-MS showed good linearity, precision, accuracy, wide measuring range of detection, and lower LLOQ. This method will be very useful to evaluate the status of dietary iodine intake and the appropriateness of LID in thyroid cancer patients, thereby maximizing the effect of RAIT.
Adult ; Diet ; Female ; Humans ; Iodine/*urine ; Limit of Detection ; Male ; Mass Spectrometry/*methods ; Middle Aged ; Reproducibility of Results ; Thyroid Neoplasms/*radiotherapy/urine

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

BACKGROUND: The urinary iodine micromethod (UIMM) is a modification of the conventional method and its performance needs evaluation. METHODS: UIMM performance was evaluated using the method validation and 2008 Iodine Deficiency Disorders survey data obtained from four urinary iodine (UI) laboratories. Method acceptability tests and Sigma quality metrics were determined using total allowable errors (TEas) set by two external quality assurance (EQA) providers. RESULTS: UIMM obeyed various method acceptability test criteria with some discrepancies at low concentrations. Method validation data calculated against the UI Quality Program (TUIQP) TEas showed that the Sigma metrics were at 2.75, 1.80, and 3.80 for 51+/-15.50 microg/L, 108+/-32.40 microg/L, and 149+/-38.60 microg/L UI, respectively. External quality control (EQC) data showed that the performance of the laboratories was within Sigma metrics of 0.85-1.12, 1.57-4.36, and 1.46-4.98 at 46.91+/-7.05 microg/L, 135.14+/-13.53 microg/L, and 238.58+/-17.90 microg/L, respectively. No laboratory showed a calculated total error (TEcalc)iodine deficiency levels and variable performance at other concentrations according to different TEas.
Humans ; Iodine/*urine ; Laboratories/standards ; Quality Control ; Spectrophotometry/*standards ; Urinalysis/*standards

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

China ; epidemiology ; Female ; Goiter ; chemically induced ; epidemiology ; Humans ; Iodine ; administration & dosage ; urine ; Male