U-Shaped Associations Between Urinary Iodine Concentration and the Prevalence of Metabolic Disorders: A Cross-Sectional Study.

Abstract

Background: Iodine is important in both thyroid function and human metabolism. Studies have explored the effect of iodine on metabolic disorders through thyroid function. This study aimed to investigate the relationship between iodine status and metabolic disorders, such as metabolic syndrome (MetS), hypertension, impaired glucose metabolism, central obesity, and dyslipidemia. Methods: A total of 51,795 subjects aged ≥18 years from the TIDE (Thyroid Disorders, Iodine Status and Diabetes, a national epidemiological cross-sectional study) program were included. The prevalence of metabolic disorders and its related diseases was calculated based on the level of urinary iodine concentrations (UICs) using the chi-square method. To further explore whether the prevalence was associated with UIC, quadratic and UIC-stratified logistic regression models were used. Results: The prevalence of metabolic disorders as a function of UIC was found to be U-shaped with a lower prevalence of 76.0% at an UIC of 300-499 μg/L. Participants with an UIC of 300-499 μg/L showed an association with metabolic disorders (odds ratio [OR] = 0.857, 95% confidence interval [CI 0.796-0.922]) and hypertension (OR = 0.873 [CI 0.814-0.936]). An UIC of 300-799 μg/L was found to be associated with the occurrence of MetS and impaired glucose tolerance. An UIC of 500-799 μg/L was associated with the occurrence of prediabetes (OR = 0.883 [CI 0.797-0.978]). An UIC of ≥300 μg/L was associated with the occurrence of hypertriglyceridemia, hypercholesterolemia, and high levels of low-density lipoprotein cholesterol. Furthermore, an UIC of <100 μg/L showed an association with hypertension (OR = 1.097 [CI 1.035-1.162]) and hypercholesterolemia (OR = 1.178 [CI 1.117-1.242]). Conclusions: The association between UICs in adults and metabolic disorders and its related diseases is U-shaped. The association between UIC and metabolic disorders disappears in cases of iodine deficiency (<100 μg/L) or excess (≥500 μg/L).

• Authors: Mingyue Jin, Zhuo Zhang, Yongze Li, Di Teng, Xiaoguang Shi, Jianming Ba, Bing Chen, Jianling Du, Lanjie He, Xiaoyang Lai, Xiaochun Teng, Yanbo Li, Haiyi Chi, Eryuan Liao, Chao Liu, Libin Liu, Guijun Qin, Yingfen Qin, Huibiao Quan, Bingyin Shi, Hui Sun, Xulei Tang, Nanwei Tong, Guixia Wang, Jin-An Zhang, Youmin Wang, Yuanming Xue, Li Yan, Jing Yang, Lihui Yang, Yongli Yao, Zhen Ye, Qiao Zhang, Lihui Zhang, Jun Zhu, Mei Zhu, Guang Ning, Yiming Mu, Jiajun Zhao, Weiping Teng, Zhongyan Shan
• Journal: Thyroid : official journal of the American Thyroid Association (Thyroid) Vol. 30 Issue 7 Pg. 1053-1065 (07 2020) ISSN: 1557-9077 [Electronic] United States
• PMID: 32188373 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Blood Glucose
• Cholesterol, LDL
• Iodine

Topics

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Blood Glucose (metabolism)
• China (epidemiology)
• Cholesterol, LDL (blood)
• Cross-Sectional Studies
• Dyslipidemias (blood, epidemiology, urine)
• Female
• Humans
• Hypertension (blood, epidemiology, urine)
• Iodine (urine)
• Male
• Metabolic Diseases (blood, epidemiology, urine)
• Metabolic Syndrome (blood, epidemiology, urine)
• Middle Aged
• Nutritional Status
• Prevalence
• Young Adult