The Effects of Long-Term High Water Iodine Levels in the External Environment on the Carotid Artery

Ji Bian,Jie Gao,Wen Jiang,Xiaoming Wang,Feng Li,Zijing Liu,Zhexue Wei,Man Zhang,Jianchao Bian

doi:10.1007/s12011-021-02872-2

Abstract

Iodine excess typically affects thyroid function in the human body and may damage carotid artery. Four investigation plots with different water iodine levels were selected in Shandong Province, China. These included a low, medium, and high iodine group and an iodine excess group whose water iodine content was < 10, 50–150, 150–300, and > 300 μg/L, respectively. Residents aged 20–65 years answered a questionnaire and underwent carotid artery ultrasonography, and their height, weight, and urinary iodine concentrations were measured. A total of 2026 individuals participated in the study. Urinary iodine concentration increased with increased water iodine levels. The medial thickening rate and intimal roughness rate in the iodine excess group were significantly higher than in the other three groups. After controlling for factors such as gender, age, and BMI, iodine excess remained as a risk factor for carotid intima-media thickening. Excess water iodine in the external environment is a risk factor for intima-media thickening of the carotid artery, suggesting that iodine excess may cause vascular injury and promote atherosclerosis.

Highlights

Excessive iodine intake may cause disease, and its sources typically include food, water, and iatrogenesis
The distribution of urinary iodine in each group differed significantly, and the median urinary iodine concentration in each group increased with the increase in water iodine content
Our current study found that water iodine levels > 300 μg/L were an independent risk factor for carotid intima-media thickening

Summary

Introduction

Excessive iodine intake may cause disease, and its sources typically include food, water, and iatrogenesis. In 1965, Suzuki[1] reported that seaweed intake was responsible for the high prevalence of goiter in Hokkaido, Japan. In 1978, a study found that excess water iodine caused goiter in China[2]. Iatrogenic iodine excess most commonly occurs as a side effect of drugs, among which amiodarone is a common example[3]. Iodine excess typically affects thyroid function in the human body and may cause diseases such as goiter, hyperthyroidism, hypothyroidism, and autoimmune thyroid disease[4, 5]. Some studies have found that iodine excess affects intellectual development[6]. The effects of iodine excess on the cardiovascular system are still largely undetermined

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Conclusion