Department of Maternal, Child and Adolescent Health, School of Public Health, Guangxi Medical University, Nanning 530021, Guangxi, China; Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, Guangxi, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning 530021, Guangxi, China.
Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, Guangxi, China.
Neurotoxicology. 2021 Jan;82:177-185. doi: 10.1016/j.neuro.2020.10.010. Epub 2020 Oct 25.
Lead exposure is one of the most concerning public health problems worldwide, particularly among children. Yet the impact of chronic lead exposure on the thyroid status and related intelligence quotient performance among school-age children remained elusive.
The aim of this study was to evaluate the influence of lead exposure on the thyroid hormones, amino acid neurotransmitters balances, and intelligence quotient (IQ) among school-age children living nearby a lead-zinc mining site. Other factors such as rice lead levels, mothers' smoking behavior, and diet intake were also investigated.
A total of 255 children aged 7-12 years old were recruited in this study. Blood lead level (BLL), thyroid hormones including free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH), and amino acid neurotransmitters such as glutamate (Glu), glutamine (Gln), and γ-aminobutyric acid (GABA) were measured using graphite furnace atomic absorption spectroscopy (GFAAS), chemiluminescence immunoassay, high performance liquid chromatography (HPLC). Raven's standard progressive matrices (SPM) and the questionnaire were used to determine IQ and collect related influence factors.
The average BLL of children was 84.8 μg/L. The occurrence of lead intoxication (defined as the BLL ≥ 100 μg/L) was 31.8%. Serum TSH levels and IQ of lead-intoxicated children were significantly lower than those without lead toxicity. The GABA level of girls with the lead intoxication was higher than those with no lead-exposed group. Correlation analyses revealed that BLL were inversely associated with the serum TSH levels (R= -0.186, p < 0.05), but positively related with IQ grades (R = 0.147, p < 0.05). Moreover, BLL and Glu were inversely correlated with IQ. In addition, this study revealed four factors that may contribute to the incidence of lead intoxication among children, including the frequency of mother smoking (OR = 3.587, p < 0.05) and drinking un-boiled stagnant tap water (OR = 3.716, p < 0.05); eating fresh fruits and vegetables (OR = 0.323, p < 0.05) and soy products regularly (OR = 0.181, p < 0.05) may protect against lead intoxication.
Lead exposure affects the serum TSH, GABA levels and IQ of school-aged children. Developing good living habits, improving environment, increasing the intake of high-quality protein and fresh vegetable and fruit may improve the condition of lead intoxication.
铅暴露是全球最令人关注的公共卫生问题之一，尤其是在儿童中。然而，慢性铅暴露对学龄儿童甲状腺功能和相关智商表现的影响仍不清楚。
本研究旨在评估在附近铅锌矿区生活的学龄儿童中，铅暴露对甲状腺激素、氨基酸神经递质平衡和智商（IQ）的影响。还研究了其他因素，如大米铅含量、母亲吸烟行为和饮食摄入。
本研究共招募了 255 名 7-12 岁的儿童。使用石墨炉原子吸收光谱法（GFAAS）、化学发光免疫分析法和高效液相色谱法（HPLC）测量血铅水平（BLL）、甲状腺激素（包括游离三碘甲状腺原氨酸（FT3）、游离甲状腺素（FT4）和促甲状腺激素（TSH））和氨基酸神经递质（如谷氨酸（Glu）、谷氨酰胺（Gln）和γ-氨基丁酸（GABA）。瑞文标准渐进矩阵（SPM）和问卷用于确定 IQ 并收集相关影响因素。
儿童的平均 BLL 为 84.8μg/L。铅中毒（定义为 BLL≥100μg/L）的发生率为 31.8%。铅中毒儿童的血清 TSH 水平和智商明显低于无铅毒性儿童。铅中毒女孩的 GABA 水平高于无铅暴露组。相关性分析显示，BLL 与血清 TSH 水平呈负相关（R=-0.186，p<0.05），但与 IQ 等级呈正相关（R=0.147，p<0.05）。此外，BLL 和 Glu 与 IQ 呈负相关。此外，本研究还揭示了四个可能导致儿童铅中毒的因素，包括母亲吸烟频率（OR=3.587，p<0.05）和饮用未煮沸的死水（OR=3.716，p<0.05）；经常食用新鲜水果和蔬菜（OR=0.323，p<0.05）和豆制品（OR=0.181，p<0.05）可能有助于预防铅中毒。
铅暴露影响学龄儿童的血清 TSH、GABA 水平和智商。养成良好的生活习惯、改善环境、增加优质蛋白质和新鲜蔬菜、水果的摄入可能有助于改善铅中毒状况。
