Association between heavy metal exposure level and physical development indicators among school-age children

Qiaorou Zhang; Yun Cao; Ying Tian; Xiaoning Lei; Chengyu Pan; Cheng Lyu; Rong Shi

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Association between heavy metal exposure level and physical development indicators among school-age children

VernacularTitle:学龄期儿童重金属暴露水平与其体格发育相关指标的关联性研究
Author: Qiaorou ZHANG ¹ ; Yun CAO ² ; Ying TIAN ^{3
,

4} ; Xiaoning LEI ¹ ; Chengyu PAN ¹ ; Cheng LYU ¹ ; Rong SHI ¹
Author Information

1. Department of Environmental Health, Shanghai Jiao Tong University School of Public Health, Shanghai 200025, China.
2. Department of Physical and Chemical Laboratory, Shanghai Huangpu District Center for Disease Control and Prevention, Shanghai 200025, China.
3. Department of Environmental Health, Shanghai Jiao Tong University School of Public Health, Shanghai 200025, China
4. MOE-Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
Publication Type:Selectedarticle
Keywords: heavy metal; urinary cadmium; physical development; sex difference; body mass index
From: Journal of Environmental and Occupational Medicine 2022;39(2):127-132
CountryChina
Language:Chinese
Abstract: Background Heavy metals are widely present in the environment, difficult to degrade, and bioaccumulative. Children's physical development are not mature, and exposure to heavy metals which may cause irreversible harm to them. However, the current research conclusions are still inconsistent. Therefore, it is very important to pay attention to the impact of heavy metal pollutants on physical development. Objective To detect the level of heavy metal exposure of school-age children in Laizhou Wan, Shandong Province, and to explore the relationship between heavy metal exposure level and physical development indexes of school-age children. Methods The subjects of this study were 318 children born to pregnant women recruited from Laizhou Wan Birth Cohort in Shandong Province from September 2010 to December 2013. The school-age children at age 7 were followed up from July to September 2019. Their urine samples were collected and the levels of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) in urine were detected by inductively coupled plasma mass spectrometry (ICP-MS). At the same time, the height, weight, body mass index (BMI), waist circumference, and body fat percentage of the children were evaluate to analyze the relationship between the four heavy metals in children's urine and the indicators related to children's physical development. Results Among the 318 school-age children with an age (\begin{document}$\bar x \pm s $\end{document}) of (7.77±0.67) years, the median (P₂₅, P₇₅) levels of As, Cd, Pb, and Hg in urine were 73.98 (44.81, 124.61), 0.40 (0.27, 0.58), 1.20 (0.71, 1.72), and 2.38 (1.32, 4.80) µg·g⁻¹ (of creatinine), respectively. The children’s urinary Cd level was positively correlated with their weight, BMI, and waist circumference (P<0.05), and corresponding regression coefficients (b) and its 95% confidence intervals (CI) were 0.99 (0.14-1.83), 0.43 (0.06-0.81), and 1.35 (0.27-2.42), respectively; while the other heavy metals were not related to the above physical development indicators (P>0.05). After sex stratification, it was found that boys’ urinary Cd level was positively correlated with their height, weight, BMI, and waist circumference (P <0.05) with associated b (95%CI) of 1.73 (0.53-2.93), 2.03 (0.60-3.47), 0.75 (0.11-1.38), and 2.66 (0.85-4.47), respectively; such associations were not found in girls. After further stratification of boys’ BMI according to normal, overweight, and obesity, it was found that a higher urinary Cd level was correlated with an increased risk of obesity in boys (P<0.05), and the associated b (95%CI) was 2.34 (1.02-5.36). Conclusion The level of urinary Cd exposure of boys in Laizhou Wan, Shandong Province is positively correlated with their height, weight, BMI, and waist circumference, and may be related to obesity in boys.