Minoru Irie

National Research Institute for Child Health and Development, Tokyo, Edo, Tōkyō, Japan

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Publications (5)17.71 Total impact

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    ABSTRACT: Table 3 contains some typographical errors. Median (IQR) of FT4 should be median (5-95th percentile) and the median (IQR) values of TSH are replaced with median (5-95th percentile) values.
    Endocrine Journal 01/2014; 61(7):743. · 2.23 Impact Factor
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    ABSTRACT: Iodine is an essential nutrient for thyroid hormone synthesis, and iodine deficiency especially in pregnant and lactating women results in serious damage to their infants. To characterize iodine nutrition throughout gestation by using a food frequency questionnaire (FFQ) and urinary iodine concentration (UIC) measurement, and to establish appropriate gestational age-specific reference ranges for serum TSH and FT4 in thyroid autoantibody (ThAb) negative euthyroid Japanese women, a total number of 563 pregnant women including 422 subjects with negative ThAbs, 105 postpartum women and their 297 newborn infants were included in the study. Dietary iodine intake (DII) was evaluated by FFQ. Serum TSH, FT4 and UIC were sequentially determined in the three trimesters of pregnancy and at the 31st postpartum day. The overall median UICs throughout pregnancy and in the postpartum period were 224.0 and 135.0μg/L, respectively, suggesting sufficient iodine nutrition. The median DII was 842.4μg/day in pregnant women. The median UIC in the first trimester (215.9μg/L) significantly decreased in the second trimester (136.0μg/L). The prevalence of pregnant women with a UIC below 150μg/L was 31.6% and that in lactating women with a UIC below 100μg/L was 33.3%. The pattern of gestational change in serum TSH and FT4 was comparable to that in iodine-sufficient areas. A substantial percentage of women might be at risk for iodine deficiency if there is a restriction of iodine-rich foods. However, iodine supplementation for pregnant women must be carefully balanced against the risk of iodine excess particularly in Japan. Further research in larger samples is needed.
    Endocrine Journal 06/2013; · 2.23 Impact Factor
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    ABSTRACT: Iodine deficiency in pregnant and lactating women results in serious damage to their fetuses, newborns, and weaning infants. The effect of dietary iodine intake on maternal and infantile thyroid function has not been well studied in iodine-sufficient areas, and there are few data on appropriate gestational age-specific reference ranges for urinary iodine excretion during pregnancy and lactation. The aim of the study was to characterize the gestational change of urinary iodine excretion in Japanese women and to assess the effects of iodine status on thyroid function in mother and infant. A total of 934 Japanese women and their 722 newborn infants were enrolled in the study. Iodine and creatinine concentrations were determined in spot urine samples in the three trimesters of pregnancy and the postpartum period at 34.0 d after delivery. Serum thyroperoxidase antibody and thyroglobulin antibody, TSH, and free T(4) were measured in each trimester, and neonatal TSH was measured on postnatal d 4. The overall median urinary iodine concentration (UIC) during pregnancy was 219.0 μg/liter, higher than that in postpartum women (135.0 μg/liter). The prevalence of pregnant women with low UIC less than 100 μg/liter or high UIC greater than 500 μg/liter was 16.1 and 22.2%, respectively. Urinary iodine excretion decreased from 221.0 μg/liter in the first trimester to 208.0 μg/liter in the second trimester to 193.0 μg/liter in the third trimester, and then remained at 135.0 μg/liter postpartum. [corrected]. The maternal UIC correlated positively with serum TSH during pregnancy. There was no significant difference in UIC between subjects with positive thyroid autoantibodies and those with negative antibodies. Iodine intake assessed by UIC in Japanese pregnant women is regarded as sufficient and not excessive according to World Health Organization criteria. Although the data are local, our results provide additional information on the reference range for UIC throughout gestation in iodine-sufficient areas.
    The Journal of Clinical Endocrinology and Metabolism 09/2011; 96(12):3846-54. · 6.31 Impact Factor
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    ABSTRACT: Iodine deficiency disorders (IDDs) are serious global public health problems and approximately 2 billion people are at risk of IDD complications. Urine iodine and thyroid size by ultrasound in school-age children are important indicators for assessing IDD in a population. Interpretation of sonographically measured thyroid volume requires valid reference criteria from iodine-sufficient populations, and in 2003 WHO (World Health Organization)/ICCIDD (International Council for the Control of Iodine Deficiency Disorders) proposed new international reference values for thyroid volume in children aged 6-12 years. To establish a normative reference of thyroid volume and characterize the current status of iodine nutrition in Japanese schoolchildren in Tokyo, where iodine deficiency has never existed, a total of 654 subjects aged 6-12 years (317 girls and 337 boys) in three primary schools were enrolled in the study in 2002. Thyroid volume was determined by using the standardized method recommended by WHO/ICCIDD and the iodine concentration in spot urine samples and the anthropometric measurements were evaluated. Thyroid volume was positively correlated with the children's age, height, weight, or BSA. Regardless of gender the computed median and 97th percentile thyroid volumes based on age or BSA in Japanese children were generally lower than the corresponding values recently reported in iodine-sufficient areas, although these values were slightly higher (5-13%) than those in the 2003 WHO/ICCIDD international reference. The computed median value of urinary iodine concentration was 281.6 microg/L (303.7 microg/gCre) and extremely high values exceeding 1,000 microg/L were found in 16% of the subjects. The present study clearly indicated a high iodine intake in Japanese schoolchildren and also established reference values for thyroid volume that might be applicable to countries in the Far East as a population-specific local reference.
    Thyroid 03/2007; 17(2):145-55. · 3.54 Impact Factor
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    ABSTRACT: Although endemic goiter had been recognized in most parts of the country, there are few available data on iodine-deficiency disorders (IDDs) in Mongolia. This study aimed to characterize the current status of iodine deficiency in Ulaan Baatar, Mongolia's capital city. Cross-sectional, observational study designed and performed according to the surveillance methods for IDD prevalence recommended by WHO/UNICEF/ICCIDD. A total of 505 schoolchildren aged 9-14 years (237 girls and 268 boys) and 138 mothers and their neonatal infants were selected to clinical and biochemical examination of the thyroid in 1996 and 1999. The anthropometric measurements, thyroid volume determined by ultrasound, blood TSH and FT4 concentrations, urinary iodine concentration and iodine content of salt consumed in households. Median thyroid volumes based on age were generally higher than those in iodine-sufficient areas and comparative to those reported in mild iodine-deficiency areas. Application of the updated WHO/ICCIDD reference values in iodine-replete European schoolchildren to the Mongolian children aged 10-12 years resulted in a goiter prevalence of 43.3%. The median value of urinary iodine concentration was 152.5 micro g/l (1.20 micro mol/l) and 40.3% of children excreted iodine below 100 micro g/l. Iodized salt (> 40 ppm) was consumed in 63.1% of households and in the children using noniodized salt their urinary iodine concentration was lower than those using ionized salt. In postpartum women, median thyroid volume and urinary iodine concentration were 11.3 ml and 107 micro g/l (0.84 micro mol/l), respectively, and 46% of women excreted less than 100 micro g/l (0.79 micro mol/l) of iodine. Of their neonates, 17.8% had elevated blood TSH levels (> 5 mU/l). In a 1999 survey, the goiter prevalence and ratio of low iodine excretion in schoolchildren decreased to 29.8% and 31.3%, respectively, while median urinary iodine concentration remain unchanged (160 micro g/l; 1.26 micro mol/l). The present study clearly indicates the presence of mild iodine deficiency in Mongolia. Enlarged thyroid gland and normal iodine excretion observed in schoolchildren living in Ulaan Baatar may result from the residual effects of iodine deficiency previously and presumably still exist in the city. Slight reduction in the rate of children with enlarged thyroid and low urinary iodine excretion after the onset of national iodinization programme suggests incomplete normalization of thyroid volume in children and that the correction of iodine deficiency is now in progress in Ulaan Baatar. Further nationwide surveys together with monitoring the progress of the national programme eliminating IDD are required in suburban areas surrounding the city and also in rural areas.
    Clinical Endocrinology 09/2003; 59(3):298-306. · 3.40 Impact Factor

Publication Stats

25 Citations
17.71 Total Impact Points

Institutions

  • 2011–2013
    • National Research Institute for Child Health and Development, Tokyo
      Edo, Tōkyō, Japan
  • 2007
    • Toho University
      • Department of Neonatology
      Edo, Tōkyō, Japan
  • 2003
    • The University of Tokyo
      • Department of International Health
      Edo, Tōkyō, Japan