Department of Chemistry, College of Natural Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda.
Department of Neurology, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA.
Chemosphere. 2024 Sep;364:143191. doi: 10.1016/j.chemosphere.2024.143191. Epub 2024 Aug 29.
Nodding syndrome (NS) is a neurologic disorder of unknown etiology characterized by vertical head nodding that has affected children aged 5-18 years in East Africa. Previous studies have examined relationships with biological agents (e.g., nematodes, measles, and fungi), but there is limited data on the possible contributions of neurotoxic environmental chemicals frequently used as pesticides/insecticides to the development and progression of this disorder. We examined the levels of persistent organochlorine pesticides (OCPs) in children (5-18 years old) from Kitgum District, Northern Uganda. These children previously lived in internally displaced people's (IDP) camps, where they were exposed to various health risks, including contaminated food and water. Exposure to OCPs through contaminated food and water is postulated here as a potential contributor to NS etiology. We analyzed serum (n = 75) and urine (n = 150) samples from children diagnosed with NS, and from seizure-free household controls (HC), and community controls (CC). Samples were extracted using solid-phase extraction (SPE) and extracts were analyzed for OCPs using gas chromatography with a triple quadrupole mass spectrometry (GC-MS/MS). Mean levels of total (∑) ∑OCPs in serum samples from NS, HC and CC subjects were 23.3 ± 2.82, 21.1 ± 3.40 and 20.9 ± 4.24 ng/mL, respectively, while in urine samples were 1.86 ± 1.03, 2.83 ± 1.42, and 2.14 ± 0.94 ng/mL, respectively. Correlation and linear regression analysis indicated that potential markers for ∑hexachlorocyclohexanes (HCHs), ∑chlordane compounds (CHLs), ∑endosulfan and ∑dichlorodiphenyltrichloroethanes (DDTs) were γ-HCH, heptachlor-exo-epoxide, endosulfan-α and p,p'-DDD in NS cases while in controls were α -HCH, heptachlor, endosulfan-α and p,p'-DDE, respectively. Since, in some instances, higher OCP levels were found in controls vs. NS cases, we conclude that exposure to organochlorine pesticides is unlikely to be associated with the etiology of NS.
点头综合征（NS）是一种病因不明的神经系统疾病，其特征为垂直性头部点头，影响东非 5-18 岁的儿童。先前的研究已经研究了与生物制剂（例如线虫、麻疹和真菌）的关系，但有关经常用作杀虫剂/杀虫剂的神经毒性环境化学物质对这种疾病的发展和进展的可能贡献的数据有限。我们检查了北乌干达基特古姆区 5-18 岁儿童（儿童）的持久性有机氯农药（OCP）水平。这些儿童以前居住在国内流离失所者（IDP）营地中，他们在那里面临各种健康风险，包括受污染的食物和水。据推测，通过受污染的食物和水接触 OCP 是 NS 病因的一个潜在因素。我们分析了患有 NS 的儿童的血清（n=75）和尿液（n=150）样本，以及无癫痫发作的家庭对照（HC）和社区对照（CC）的样本。使用固相萃取（SPE）提取样品，并用气相色谱三重四极杆质谱联用仪（GC-MS/MS）分析提取物中的 OCP。NS、HC 和 CC 组血清样本中总（∑）∑OCP 的平均水平分别为 23.3±2.82、21.1±3.40 和 20.9±4.24ng/mL，尿液样本中的平均水平分别为 1.86±1.03、2.83±1.42 和 2.14±0.94ng/mL。相关性和线性回归分析表明，∑六氯环己烷（HCHs）、∑氯丹化合物（CHLs）、∑硫丹和∑滴滴涕（DDTs）的潜在标志物为γ-HCH、七氯-外-环氧、硫丹-α和 p,p'-DDD 在 NS 病例中，而在对照组中分别为α-HCH、七氯、硫丹-α和 p,p'-DDE。由于在某些情况下，对照组的 OCP 水平高于 NS 病例，因此我们得出结论，接触有机氯农药不太可能与 NS 的病因有关。
