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Nationwide Representative Survey of Dietary Iodine Intake and Urinary Excretion in Postpartum Korean Women. Nutrients 2021; 13:nu13113955. [PMID: 34836212 PMCID: PMC8623058 DOI: 10.3390/nu13113955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/31/2021] [Accepted: 11/03/2021] [Indexed: 11/17/2022] Open
Abstract
Iodine is an essential component of thyroid hormones, but excessive iodine intake can lead to thyroid dysfunction. Traditionally, Korean mothers consume brown seaweed soup (miyeokguk), a high source of iodine, after childbirth. There is controversy regarding the effects of excessive postpartum iodine intake on the health of mothers and infants. Thus far, there have been no nationwide large-scale surveys regarding the status of iodine intake among postpartum women in Korea. Therefore, we conducted a nationwide survey of postpartum dietary iodine intake among Korean women. In total, 1054 Korean women aged ≥19 years, at less than 8 weeks postpartum, participated in this survey. Dietary data were collected using self-reported 2-day dietary records, along with before-and-after meal photos. To evaluate the correlation between dietary iodine and urinary iodine excretion (UIE), spot urine, and 24 h urine samples were collected from 98 and 29 participants, respectively. The mean daily iodine intake among all participants was 2945.6 μg, and it gradually decreased over time after childbirth. Dietary iodine intake was significantly correlated with 24 h UIE (r = 0.396, p < 0.05) and spot urine UIE (r = 0.312, p < 0.05). Follow-up studies are required to examine the influence of excessive postpartum iodine intake on thyroid health in mothers and their infants.
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Kim K, Cho SW, Park YJ, Lee KE, Lee DW, Park SK. Association between Iodine Intake, Thyroid Function, and Papillary Thyroid Cancer: A Case-Control Study. Endocrinol Metab (Seoul) 2021; 36:790-799. [PMID: 34376043 PMCID: PMC8419609 DOI: 10.3803/enm.2021.1034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 07/02/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND This study aimed to assess the effects of iodine intake, thyroid function, and their combined effect on the risk of papillary thyroid cancer (PTC) and papillary thyroid microcarcinoma (PTMC). METHODS A case-control study was conducted including 500 community-based controls who had undergone a health check-up, and 446 overall PTC cases (209 PTC and 237 PTMC) from the Thyroid Cancer Longitudinal Study. Urinary iodine concentration (UIC), was used as an indicator of iodine intake, and serum for thyroid function. The risk of PTC and PTMC was estimated using unconditional logistic regression. RESULTS Excessive iodine intake (UIC ≥220 μg/gCr) was associated with both PTC (odds ratio [OR], 18.13 95% confidence interval [CI], 8.87 to 37.04) and PTMC (OR, 8.02; 95% CI, 4.64 to 13.87), compared to adequate iodine intake (UIC, 85 to 219 μg/gCr). Free thyroxine (T4) levels ≥1.25 ng/dL were associated with PTC (OR, 1.97; 95% CI, 1.36 to 2.87) and PTMC (OR, 2.98; 95% CI, 2.01 to 4.41), compared to free T4 levels of 0.7 to 1.24 ng/dL. Individuals with excessive iodine intake and high free T4 levels had a greatly increased OR of PTC (OR, 43.48; 95% CI, 12.63 to 149.62), and PTMC (OR, 26.96; 95% CI, 10.26 to 70.89), compared to individuals with adequate iodine intake and low free T4 levels. CONCLUSION Excessive iodine intake using creatinine-adjusted UIC and high free T4 levels may have a synergistic effect on PTC and PTMC. Considering both iodine intake and thyroid function is important to assess PTC and PTMC risk.
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Affiliation(s)
- Kyungsik Kim
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul,
Korea
- Department of Biomedical Science, Seoul National University Graduate School, Seoul,
Korea
- Cancer Research Institute, Seoul National University, Seoul,
Korea
| | - Sun Wook Cho
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
| | - Young Joo Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul,
Korea
| | - Kyu Eun Lee
- Cancer Research Institute, Seoul National University, Seoul,
Korea
- Department of Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul,
Korea
- Division of Surgery, Thyroid Center, Seoul National University Cancer Hospital, Seoul,
Korea
- Integrated Major in Innovative Medical Science, Seoul National University College of Medicine, Seoul,
Korea
| | - Dong-Wook Lee
- Department of Family Medicine, Dongguk University College of Medicine, Gyeongju,
Korea
| | - Sue K. Park
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul,
Korea
- Cancer Research Institute, Seoul National University, Seoul,
Korea
- Integrated Major in Innovative Medical Science, Seoul National University College of Medicine, Seoul,
Korea
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Kim HJ, Kazmi SZ, Kang T, Sohn SY, Kim DS, Hann HJ, Ahn HS. Familial Risk of Hashimoto's Thyroiditis Among First-Degree Relatives: A Population-Based Study in Korea. Thyroid 2021; 31:1096-1104. [PMID: 33514269 DOI: 10.1089/thy.2020.0213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background: Few small-scale studies have reported a genetic and familial predisposition in Hashimoto's thyroiditis (HT), however, quantified familial risk estimates from population-level data are unavailable. We aimed to estimate the incidence and familial risk of HT among first-degree relatives (FDR) according to age, sex, and family relationships. Methods: We conducted a population-based study in the general population of Korea from 2002 to 2017. Using the nationwide health insurance database, which has full population coverage and family relationship information, a cohort of 22 million individuals with blood-related FDR comprising 12 million families were followed up for a familial occurrence of HT. Age- and sex-adjusted incidence risk ratios (IRRs) were calculated in individuals with an affected FDR compared with those without an affected FDR. Results: Among 21,940,795 individuals, 234,912 had an HT-affected FDR, of whom 2425 familial cases developed HT with an incidence of 7.12/10,000 person-years. The familial risk for HT was 6.5-fold (95% confidence interval [CI]: 6.24-6.78) higher in individuals with versus without affected FDR. According to relationship, familial risks were IRR 102.71, IRR 7.80, IRR 5.54, and IRR 5.52 with an affected twin, sibling, mother, and father, respectively, and the corresponding incidence (/10,000 person-years) was 115.57, 10.66, 5.73, and 5.91. Same-sex twins had three times higher risk of developing HT than opposite-sex twins (IRR 121.01 vs. 21.46). The sex-specific familial risk was higher in males than females. The risks demonstrated age dependence, being higher in younger age groups. Conclusions: This study represents the largest population-based study of familial HT risk in Asia. We demonstrated elevated familial risk of incident HT among FDR, but with lower magnitude as those observed in previous studies. Familial risk increased with the degree of genetic relatedness among FDR indicating a prominent role of genetic factors in the familial aggregation of HT. Elevated risks in the younger age groups should motivate clinicians to screen people with a family history, especially those <30 years.
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Affiliation(s)
- Hyun Jung Kim
- Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Korea
| | - Sayada Zartasha Kazmi
- Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Korea
| | - Taeuk Kang
- Korean Research-Based Pharma Industry Association (KRPIA), Seoul, Korea
| | - Seo Young Sohn
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Hanyang University College of Medicine, Myongji Hospital, Goyang, Korea
| | - Dong-Sook Kim
- Health Insurance Review and Assessment Service (HIRA), Wonju, Korea
| | - Hoo Jae Hann
- Medical Research Institute, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Hyeong Sik Ahn
- Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Korea
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Park JK, Woo HW, Kim MK, Shin J, Lee YH, Shin DH, Shin MH, Choi BY. Dietary iodine, seaweed consumption, and incidence risk of metabolic syndrome among postmenopausal women: a prospective analysis of the Korean Multi-Rural Communities Cohort Study (MRCohort). Eur J Nutr 2020; 60:135-146. [PMID: 32211932 DOI: 10.1007/s00394-020-02225-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 03/09/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE Despite a beneficial role of iodine and seaweed consumption against metabolic syndrome (MetS), which is high in postmenopausal women, few studies investigated such associations in a prospective study. This study aimed to investigate the association of dietary iodine and seaweed consumption with the incidence of MetS and its components in postmenopausal women. METHODS A total of 2588 postmenopausal women aged ≥ 40 years were recruited between 2005 and 2011 in the Multi-Rural Communities Cohort (MRCohort). A validated semiquantitative food frequency questionnaire was used to collect dietary intake data. MetS was defined as three of five components [abdominal obesity, elevated blood pressure, glucose, triglyceride, and low-high density lipoprotein cholesterol (HDL-C)] and the incidence of MetS was checked every 2-4 years. The incidence rate ratio (IRR) was estimated using a modified Poisson regression model with a robust error estimator. RESULTS During the mean follow-up period (3.4 ± 2.1 years), MetS occurred in 481 participants. The median cumulative average iodine intake was 108.9 µg/day (interquartile range, 60.8-190.2 µg/day). In multivariable analyses, average iodine and seaweed consumption were inversely associated with MetS (IRR = 0.61, 95% CI 0.47-0.78 in the highest quartile of iodine intake, P for trend = 0.0018; IRR = 0.52, 95% CI 0.39-0.69 in the highest quartile of seaweed consumption, P for trend = 0.0004). Among MetS components, blood glucose (> 100 mg/dL), blood pressure (≥ 130/85 mmHg), and lipid profiles (triglyceride, ≥ 150 mg/dL and HDL-C, < 50 mg/dL) were significantly inversely associated with dietary iodine and seaweed consumption, but there was no clear association for waist circumference (≥ 85 cm). CONCLUSION Dietary iodine and seaweed consumption may be inversely associated with MetS incidence and its individual abnormalities in postmenopausal women.
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Affiliation(s)
- Jin-Kyu Park
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, South Korea
| | - Hye Won Woo
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea
- Institute for Health and Society, Hanyang University, Seoul, South Korea
| | - Mi Kyung Kim
- Department of Preventive Medicine, Medical School Building A-Room 517-2, College of Medicine, Hanyang University, 222 Wangsimni-ro, Sungdong-Gu, Seoul, 04763, Republic of Korea.
- Institute for Health and Society, Hanyang University, Seoul, South Korea.
| | - Jinho Shin
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, South Korea
| | - Young-Hoon Lee
- Department of Preventive Medicine and Institute of Wonkwang Medical Science, School of Medicine, Wonkwang University, Iksan, South Korea
| | - Dong Hoon Shin
- Department of Preventive Medicine, Keimyung University School of Medicine, Daegu, South Korea
| | - Min-Ho Shin
- Department of Preventive Medicine, Chonnam National University Medical School, Gwangju, South Korea
| | - Bo Youl Choi
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea
- Institute for Health and Society, Hanyang University, Seoul, South Korea
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The success rate of radioactive iodine therapy for Graves' disease in iodine-replete area and affecting factors: a single-center study. Nucl Med Commun 2020; 41:212-218. [PMID: 31895759 DOI: 10.1097/mnm.0000000000001138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Initial treatment options for Graves' disease include antithyroid drugs, radioactive iodine (RAI), and surgery. Because of similar effects of three modalities, initial treatment preferences differ by country to country. In Korea, iodine-replete area, RAI was used as a second-line option. For these reasons, the RAI success rate in Korea might differ from other countries. METHODS A total of 247 patients were enrolled. The primary outcome was cumulative success rate in the first year, and the secondary outcome was factors that affected the success. Delayed response, which included patients who attained successful RAI during the follow-up, after the first year without further RAI, and factors that affected the delayed response were reviewed. RESULTS The cumulative success rate in the first year was 62.8%. Higher RAI activity [odds ratio (OR) 2.56, P = 0.02], longer disease duration (OR 0.43, P = 0.01), larger goiter (OR 0.31, P = 0.01), and higher post-RAI fT4 (fT4 between upper normal limit (UNL) to 1.5 × UNL; OR 0.24; P < 0.01, 1.5 × UNL<; OR 0.08; P < 0.01) were associated with RAI success. Twenty-seven patients showed delayed response, and goiter size (P < 0.05), pre-RAI TSH receptor Ab (TRAb) level (P < 0.01) and post-RAI fT4 (P < 0.01) were associated. CONCLUSION The success rate of the first RAI in Korea was lower than that in other countries. Delayed response was observed in patients with smaller goiter, low pre-RAI TRAb, and low post-RAI fT4. In these patients, clinical follow-up with monitoring could be an option, and decision of optimal timing of first RAI is crucial.
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Kim S, Kwon YS, Kim JY, Hong KH, Park YK. Association between Iodine Nutrition Status and Thyroid Disease-Related Hormone in Korean Adults: Korean National Health and Nutrition Examination Survey VI (2013-2015). Nutrients 2019; 11:nu11112757. [PMID: 31766270 PMCID: PMC6893705 DOI: 10.3390/nu11112757] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/06/2019] [Accepted: 11/11/2019] [Indexed: 01/21/2023] Open
Abstract
This study aimed to observe the relationship between iodine nutrition status (dietary iodine intake and estimated iodine intake based on urinary iodine concentration (UIC)) and thyroid disease-related hormones. This study involved 6090 subjects >19 years old with valid UIC, assessed between 2013 and 2015 by the Korean National Health and Nutrition Examination Survey, using a stratified, multistage, clustered probability-sampling design. The estimated iodine intake in participants was measured using UIC and urine creatinine. To examine the effect of iodine intake on thyroid disease, the iodine intake was divided into Korean Dietary Reference Intakes groups, and logistic regression analysis was performed via the surveylogistic procedure to obtain odds ratios (ORs) and 95% confidence intervals (CIs). The estimated iodine intake showed a significant positive correlation with dietary iodine intake (r = 0.021, p < 0.001), UIC (r = 0.918, p < 0.001), and thyroid-stimulating hormone (TSH) (r = 0.043, p < 0.001), but a significant negative correlation with free thyroxine (FT4) (r = -0.037, p < 0.001). Additionally, as the estimated iodine intake increased, age, TSH, and UIC increased, but FT4 decreased (p for trend < 0.0001). The risk of thyroid disease was higher in the "≥tolerable upper intake level (UL ≥ 2400 µg/day)" group than in the "<estimated average requirement (EAR < 150 µg/day)" group in females (OR: 2.418; 95% CI: 1.010-5.787). Also, as iodine intake increased, the risk of thyroid disease increased (p for trend < 0.038).
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Affiliation(s)
- Sohye Kim
- Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin 17104, Korea;
- Nutrition Care Services, Seoul National University of Bundang Hospital, Seongnam 13620, Korea
| | | | - Ju Young Kim
- Department of Family Medicine, Seoul National University of Bundang Hospital, Seongnam 13620, Korea;
| | - Kyung Hee Hong
- Department of Food Science and Nutrition, Dongseo University, Pusan 47011, Korea;
| | - Yoo Kyoung Park
- Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin 17104, Korea;
- Correspondence:
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Choi YC, Cheong JI, Chueh HW, Yoo JH. Iodine status and characteristics of Korean adolescents and their parents based on urinary iodine concentration: a nationwide cross-sectional study. Ann Pediatr Endocrinol Metab 2019; 24:108-115. [PMID: 31261475 PMCID: PMC6603615 DOI: 10.6065/apem.2019.24.2.108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/12/2018] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Iodine is a major component of thyroid hormones. Both deficiency and excess of iodine are major risk factors for thyroid disease, making it important to accurately assess iodine level in the human body. Urinary iodine concentration (UIC) is a commonly used measure of iodine status. However, there is little research on iodine status and related characteristics in Korean adolescents. METHODS Using data from the sixth Korea National Health and Nutrition Examination Survey (KNHANES VI) for the years 2013-2015, we analyzed UIC and thyroid function test results in adolescents aged 10-18 years and their parents. We also investigated the influence of socioeconomic factors and family history of thyroid disease on iodine status. RESULTS Mean UIC in Korean adolescents was 963.5±55.7 μg/L. Among evaluated subjects, 6.6%±1.0%, 29.8%±1.7%, and 63.9%±1.9% had low (UIC<100 μg/L), adequate (UIC: 100-299.9 μg/L), and excess (UIC≥300 μg/L) iodine concentrations, respectively. Based on regional trends, the incidence of iodine deficiency exceeded 10% in several regions, even though there was a dominance of regions with excess iodine. Parental UIC, female sex, average monthly income, and expenditure were all found to affect the iodine status of Korean adolescents. CONCLUSION Although regional differences exist, the iodine status in Korean adolescents is mainly affected by the eating habits of their families and socioeconomic factors. Therefore, monitoring of iodine status is necessary in this population.
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Affiliation(s)
- Yun Chang Choi
- Department of Pediatrics, Dong-A University College of Medicine, Busan, Korea
| | - Ji In Cheong
- Department of Pediatrics, Dong-A University College of Medicine, Busan, Korea
| | - Hee Won Chueh
- Department of Pediatrics, Dong-A University College of Medicine, Busan, Korea
| | - Jae-Ho Yoo
- Department of Pediatrics, Dong-A University College of Medicine, Busan, Korea,Address for correspondence: Jae-Ho Yoo, MD, PhD Department of Pediatrics, Dong-University Hospital, Dong-A University College of Medicine, 26 Daesingongwon-ro, Seo-gu, Busan 49201, Korea Tel: +82-51-240-5124 Fax: +82-51-242-2765 E-mail:
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