5月28日，北京大学公布的一份研究报告显示，PM2.5对健康人群患血栓病等心脑血管疾病有明显影响。这是北大首次公布以北京地区健康人为研究样本，涉及PM2.5影响健康的研究成果。
国际权威医学期刊——《美国医学学会杂志》上周刊发了北大环境科学与工程学院教授朱彤、北大环境与健康研究中心博士黄薇和美国南加州大学全球健康研究所教授张军峰等共同完成的论文《北京奥运期间大气污染水平的变化与健康年轻人炎症和血栓形成生物标记物的关联》。
2008年北京奥运会和残奥会期间实施了大量空气污染控制措施，奥运会前后大气污染水平发生急剧变化。科研人员观测到，北京地区颗粒和气态污染物浓度水平从奥运会前至奥运会期间下降了13%至60%，其中二氧化硫浓度水平下降60%、一氧化碳下降48%、二氧化氮下降43%、PM2.5下降27%。奥运会之后，污染物的浓度水平总体上升。
科研人员在奥运前、中、后五个月密集追踪了125名北京地区健康年轻人的炎症和血栓形成等生物性标记物水平的变化。研究发现，125名志愿者的可溶性血小板选择蛋白(SCD62P)平均水平由奥运前的6.29 ng/mL降低至奥运期间的4.16 ng/mL，下降了34%；血管假性血友病因子(vWF)水平降低13.1%。这两项指标是诱发血栓形成的因素。
Association Between Changes in Air Pollution Levels During the Beijing Olympics and Biomarkers of Inflammation and Thrombosis in Healthy Young Adults
David Q. Rich, ScD; Howard M. Kipen, MD, MPH; Wei Huang, ScD; Guangfa Wang, MD; Yuedan Wang, PhD; Ping Zhu, MD; Pamela Ohman-Strickland, PhD; Min Hu, PhD; Claire Philipp, MD; Scott R. Diehl, PhD; Shou-En Lu, PhD; Jian Tong, MS; Jicheng Gong, PhD; Duncan Thomas, PhD; Tong Zhu, PhD; Junfeng (Jim) Zhang, PhD
Context Air pollution is a risk factor for cardiovascular diseases (CVD), but the underlying biological mechanisms are not well understood.
Objective To determine whether markers related to CVD pathophysiological pathways (biomarkers for systemic inflammation and thrombosis, heart rate, and blood pressure) are sensitive to changes in air pollution.
Design, Setting, and Participants Using a quasi-experimental opportunity offered by greatly restricted air pollution emissions during the Beijing Olympics, we measured pollutants daily and the outcomes listed below in 125 healthy young adults before, during, and after the 2008 Olympics (June 2-October 30). We used linear mixed-effects models to estimate the improvement in outcome levels during the Olympics and the anticipated reversal of outcome levels after pollution controls ended to determine whether changes in outcome levels were associated with changes in pollutant concentrations.
Main Outcome Measures C-reactive protein (CRP), fibrinogen, von Willebrand factor, soluble CD40 ligand (sCD40L), soluble P-selectin (sCD62P) concentrations; white blood cell count (WBC); heart rate; and blood pressure.
Results Concentrations of particulate and gaseous pollutants decreased substantially (−13% to −60%) from the pre-Olympic period to the during-Olympic period. Using 2-sided tests conducted at the .003 level, we observed statistically significant improvements in sCD62P levels by −34.0% (95% CI, −38.4% to −29.2%; P < .001) from a pre-Olympic mean of 6.29 ng/mL to a during-Olympic mean of 4.16 ng/mL and von Willebrand factor by −13.1% (95% CI, −18.6% to −7.5%; P < .001) from 106.4% to 92.6%. After adjustments for multiple comparisons, changes in the other outcomes were not statistically significant. In the post-Olympic period when pollutant concentrations increased, most outcomes approximated pre-Olympic levels, but only sCD62P and systolic blood pressure were significantly worsened from the during-Olympic period. The fraction of above-detection-limit values for CRP (percentage ≥ 0.3 mg/L) was reduced from 55% in the pre-Olympic period to 46% in the during-Olympic period and reduced further to 36% in the post-Olympic period. Interquartile range increases in pollutant concentrations were consistently associated with statistically significant increases in fibrinogen, von Willebrand factor, heart rate, sCD62P, and sCD40L concentrations.
Conclusions Changes in air pollution levels during the Beijing Olympics were associated with acute changes in biomarkers of inflammation and thrombosis and measures of cardiovascular physiology in healthy young persons. These findings are of uncertain clinical significance.
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