{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:01:00Z","timestamp":1760148060700,"version":"build-2065373602"},"reference-count":34,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2023,3,28]],"date-time":"2023-03-28T00:00:00Z","timestamp":1679961600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["81920108031","82230113","81330064","20JCZDJC00080"],"award-info":[{"award-number":["81920108031","82230113","81330064","20JCZDJC00080"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Tianjin Natural Science Foundation","award":["81920108031","82230113","81330064","20JCZDJC00080"],"award-info":[{"award-number":["81920108031","82230113","81330064","20JCZDJC00080"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Ensuring optimal iodine nutrition in pregnant women is a global public health concern. However, there is no direct data on safe tolerable upper intake levels (ULs) for pregnant women. A cross-sectional study was performed to determine the ULs of pregnant women. A total of 744 pregnant women were enrolled in this study. The median (IQR) urinary iodine concentration (UIC) in pregnant women was 150.2 (87.6, 268.0) \u03bcg\/L, and the urinary iodine excretion (UIE) over 24 h was 204.2 (116.0, 387.0) \u03bcg\/day. Compared with those with a UIE figure of between 150\u2013250 \u03bcg\/day, the reference group, the prevalence of thyroid dysfunction was 5.7 times higher (95%CI: 1.7, 19.2) in pregnant women with a UIE figure of between 450\u2013550 \u03bcg\/day, and 3.9 times higher (95%CI: 1.5, 10.3) in pregnant women with a UIE figure of \u2265550 \u03bcg\/day. Compared with an estimated iodine intake (EII) of between 100\u2013200 \u03bcg\/day, the reference group, the prevalence of thyroid dysfunction was 4.3 times higher (95%CI: 1.3, 14.4) in pregnant women with a UIE figure of between 500\u2013600 \u03bcg\/day, and 3.6 times higher (95%CI: 1.5, 8.9) in pregnant women with UIE of \u2265600 \u03bcg\/day. In general, our cross-sectional study found that excessive iodine intake during pregnancy appears to directly increase the risk of thyroid dysfunction. Avoiding chronic iodine intakes of 500 \u03bcg\/day or higher or having a UIE figure of \u2265450 \u03bcg\/day is recommended for pregnant women in China.<\/jats:p>","DOI":"10.3390\/nu15071635","type":"journal-article","created":{"date-parts":[[2023,3,28]],"date-time":"2023-03-28T02:58:21Z","timestamp":1679972301000},"page":"1635","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Adverse Effects on the Thyroid of Chinese Pregnant Women Exposed to Long-Term Iodine Excess: Optimal and Safe Tolerable Upper Intake Levels of Iodine"],"prefix":"10.3390","volume":"15","author":[{"given":"Wen","family":"Wu","sequence":"first","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wenxing","family":"Guo","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Naifan","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Min","family":"Gao","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"},{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Capital Medical University, Beijing 100069, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kexin","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3799-0354","authenticated-orcid":false,"given":"Elizabeth N.","family":"Pearce","sequence":"additional","affiliation":[{"name":"Section of Endocrinology, Diabetes, and Nutrition, School of Medicine, Boston University, Boston, MA 02118, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shaohan","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhiyuan","family":"Ren","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ying","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chunxi","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6044-1137","authenticated-orcid":false,"given":"Wanqi","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China"},{"name":"Tianjin Key Laboratory of Environment, Nutrition and Public Health, Center for International Collaborative Research on Environment, Nutrition and Public Health, Tianjin 300070, China"},{"name":"Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2038","DOI":"10.3945\/jn.113.179135","article-title":"Long-term exposure to excessive iodine from water is associated with thyroid dysfunction in children","volume":"143","author":"Sang","year":"2013","journal-title":"J. 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