Tasmin Saira, Furusawa Hana, Ahmad Sk Akhtar, Faruquee M H, Watanabe Chiho
Department of Human Ecology, School of International Health, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Department of Human Ecology, School of International Health, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Environ Res. 2015 Jan;136:318-23. doi: 10.1016/j.envres.2014.08.045. Epub 2014 Nov 25.
Lead has long been recognized as a harmful environmental pollutant. People in developing countries like Bangladesh still have a higher risk of lead exposure. Previous research has suggested that the delta-aminolevulinic acid dehydratase (ALAD) genotype can modify lead toxicity and individual susceptibility. As children are more susceptible to lead-induced toxicity, this study investigated whether the ALAD genotype influenced urinary excretion of delta-aminolevulinic acid (U-ALA) among children exposed to environmental lead in Bangladesh.
Subjects were elementary schoolchildren from a semi-urban industrialized area in Bangladesh. A total of 222 children were studied. Blood and urine were collected to determine ALAD genotypes, blood lead levels and urinary aminolevulinic acid (U-ALA).
The mean BPb level was 9.7 µg/dl for the study children. BPb was significantly positively correlated with hemoglobin (p<0.01). In total, allele frequency for ALAD 1 and 2 was 0.83 and 0.17 respectively. The mean U-ALA concentration was lower in ALAD1-2/2-2 carriers than ALAD1-1 carriers for boys (p=0.001). But for girls, U-ALA did not differ significantly by genotype (p=0.26). When U-ALA was compared by genotype at the same exposure level in a multiple linear regression analysis, boys who were ALAD1-2/2-2 carriers still had a lower level of U-ALA compared to ALAD1-1 carriers.
This study provides information about the influence of ALAD polymorphism and its association with U-ALA in Bangladeshi children. Our results indicate that the ALAD1-2/2-2 genotype may have a protective effect in terms of U-ALA for environmentally lead exposed boys.
长期以来，铅一直被认为是一种有害的环境污染物。在孟加拉国等发展中国家，人们面临的铅暴露风险仍然较高。先前的研究表明，δ-氨基乙酰丙酸脱水酶（ALAD）基因型可改变铅毒性和个体易感性。由于儿童对铅诱导的毒性更为敏感，本研究调查了在孟加拉国环境铅暴露儿童中，ALAD基因型是否会影响δ-氨基乙酰丙酸（U-ALA）的尿排泄。
研究对象为来自孟加拉国一个半城市化工业区的小学生。共对222名儿童进行了研究。采集血液和尿液以确定ALAD基因型、血铅水平和尿氨基乙酰丙酸（U-ALA）。
研究儿童的平均血铅水平为9.7μg/dl。血铅与血红蛋白呈显著正相关（p<0.01）。总体而言，ALAD 1和2的等位基因频率分别为0.83和0.17。对于男孩，ALAD1-2/2-2携带者的平均U-ALA浓度低于ALAD1-1携带者（p=0.001）。但对于女孩，U-ALA在不同基因型之间无显著差异（p=0.26）。在多线性回归分析中，当在相同暴露水平下按基因型比较U-ALA时，与ALAD1-1携带者相比，ALAD1-2/2-2携带者的男孩U-ALA水平仍然较低。
本研究提供了关于ALAD多态性对孟加拉国儿童的影响及其与U-ALA相关性的信息。我们的结果表明，就U-ALA而言，ALAD1-2/2-2基因型可能对环境铅暴露男孩具有保护作用。
