Wang Bin, Pang Yiming, Zhang Yali, Zhang Le, Ye Rongwei, Yan Lailai, Li Zhiwen, Ren Aiguo
Institute of Reproductive and Child Health, Peking University/ Key Laboratory of Reproductive Health, National Health and Family Planning Commission of the People's Republic of China, Beijing, 100191, P. R. China.
Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, 100191, P. R. China.
Genes Environ. 2021 Nov 25;43(1):51. doi: 10.1186/s41021-021-00227-w.
Thorium is ubiquitous in the environment and its relationship with birth defects is still under discussion. This study aimed to investigate the associations of maternal exposure to thorium with risk of neural tube defects (NTDs) by using a case-control study, as well as the relationship between thorium exposure and the indoor air pollution from coal combustion.
This study was conducted in 11 local healthcare hospitals during 2003-2007 in Shanxi and Hebei provinces, China. A total of 774 mothers were included as participants who delivering 263 fetuses with NTDs including 123 with anencephaly, 115 with spina bifida, 18 with encephalocele, and 7 other NTD subtypes (cases), and 511 health fetuses without NTDs (controls). Their hair samples were collected as close as to the occipital posterior scalp, of which those grew from 3 months before to 3 months after conception was cut to measure the thorium concentration by inductively coupled plasma-mass spectrometry.
We found a higher hair thorium concentration in the total NTD cases with 0.901 (0.588-1.382) ng/g hair [median (inter-quartile range)] than that in the controls with a value of 0.621 (0.334-1.058) ng/g hair. Similar results were found for the three concerned NTD subtypes. Maternal hair thorium concentration above its median of the controls was associated with an increased risk of the total NTDs with an adjusted odds ratio of 1.80 [95% confidence interval (CI), 1.23-2.63)] by adjusting for all confounders. There was obvious dose-response relationship between maternal hair thorium concentration and the risk of total NTDs, as well as their two subtypes (i.e. anencephaly and spina bifida). Maternal hair thorium concentration was positive associated with their exposure level to indoor air pollution from coal combustion during cooking.
Overall, our findings revealed that maternal periconceptional thorium exposure was associated with the risk of NTDs in North China. Reducing the coal usage in the household cooking activities may decrease maternal thorium exposure level.
钍在环境中普遍存在，其与出生缺陷的关系仍在讨论中。本研究旨在通过病例对照研究调查母亲接触钍与神经管缺陷（NTDs）风险之间的关联，以及钍暴露与燃煤室内空气污染之间的关系。
本研究于2003 - 2007年在中国山西省和河北省的11家当地医疗保健医院进行。共有774名母亲作为参与者，她们分娩了263例患有NTDs的胎儿，其中123例无脑儿、115例脊柱裂、18例脑膨出和7例其他NTD亚型（病例组），以及511例无NTDs的健康胎儿（对照组）。采集她们尽可能靠近枕后头皮的头发样本，将受孕前3个月至受孕后3个月生长的头发剪下，用电感耦合等离子体质谱法测量钍浓度。
我们发现，总的NTDs病例组头发钍浓度中位数为0.901（0.588 - 1.382）ng/g头发，高于对照组的0.621（0.334 - 1.058）ng/g头发。在三种相关的NTD亚型中也发现了类似结果。在调整所有混杂因素后，母亲头发钍浓度高于对照组中位数与总的NTDs风险增加相关，调整后的优势比为1.80 [95%置信区间（CI），1.23 - 2.63]。母亲头发钍浓度与总的NTDs风险及其两种亚型（即无脑儿和脊柱裂）之间存在明显的剂量反应关系。母亲头发钍浓度与她们在烹饪期间燃煤室内空气污染的暴露水平呈正相关。
总体而言，我们的研究结果表明，华北地区母亲受孕前后接触钍与NTDs风险相关。减少家庭烹饪活动中的煤炭使用量可能会降低母亲的钍暴露水平。
