1.
Factors Affecting Arsenic Methylation in Arsenic-Exposed Humans: A Systematic Review and Meta-Analysis.
Shen, H, Niu, Q, Xu, M, Rui, D, Xu, S, Feng, G, Ding, Y, Li, S, Jing, M
International journal of environmental research and public health. 2016;(2):205
Abstract
Chronic arsenic exposure is a critical public health issue in many countries. The metabolism of arsenic in vivo is complicated because it can be influenced by many factors. In the present meta-analysis, two researchers independently searched electronic databases, including the Cochrane Library, PubMed, Springer, Embase, and China National Knowledge Infrastructure, to analyze factors influencing arsenic methylation. The concentrations of the following arsenic metabolites increase (p< 0.000001) following arsenic exposure: inorganic arsenic (iAs), monomethyl arsenic (MMA), dimethyl arsenic (DMA), and total arsenic. Additionally, the percentages of iAs (standard mean difference (SMD): 1.00; 95% confidence interval (CI): 0.60-1.40; p< 0.00001) and MMA (SMD: 0.49; 95% CI: 0.21-0.77; p = 0.0006) also increase, while the percentage of DMA (SMD: -0.57; 95% CI: -0.80--0.31; p< 0.0001), primary methylation index (SMD: -0.57; 95% CI: -0.94--0.20; p = 0.002), and secondary methylation index (SMD: -0.27; 95% CI: -0.46--0.90; p = 0.004) decrease. Smoking, drinking, and older age can reduce arsenic methylation, and arsenic methylation is more efficient in women than in men. The results of this analysis may provide information regarding the role of arsenic oxidative methylation in the arsenic poisoning process.
2.
Panel studies of air pollution on children's lung function and respiratory symptoms: a literature review.
Li, S, Williams, G, Jalaludin, B, Baker, P
The Journal of asthma : official journal of the Association for the Care of Asthma. 2012;(9):895-910
Abstract
OBJECTIVE This article reviews panel studies of air pollution on children's respiratory health and proposes future research directions. METHODS The PubMed electronic database was used to search published original epidemiological studies in peer-reviewed journals from 2000 to November 2011. Children's age was limited to ≤18 years old. A total of 33 relevant articles were obtained, with 20 articles relating to lung function, 21 articles relating to respiratory symptoms, and 8 articles examining both. RESULTS Most studies suggested the adverse effects of air pollution on children's lung function and respiratory symptoms. Particles and NO(2) showed more significant results, whereas effects of SO(2) were not consistent. A few studies indicated that O(3) interacted with temperature and sometimes seemed to be a protective factor for children's respiratory health. Negative associations between air pollutants and pulmonary health were more serious in asthmatic children than in healthy subjects. However, many outcomes depended on the number of lag days. Peak expiratory flow (PEF) was the most usual measurement for children's lung function, followed by forced expiratory volume in 1 second (FEV(1)). CONCLUSIONS There are significant adverse effects of air pollution on children's pulmonary health, especially for asthmatics. Future studies need to examine the lag effects of air pollution on children's lung function and respiratory symptoms. Ambient temperature is predicted to change worldwide due to climate change, which will threaten population health. Further research is needed to examine the effects of ambient temperature and the interactive effects between air pollution and ambient temperature on children's lung function and respiratory symptoms.