生物谷报道：北卡罗来纳州大学（University of North Carolina）的科学家表示：「道路施工扬起的灰尘可能会造成气喘病人心脏方面的问题。」研究人员发现患有气喘的人，闻到室外含有粗糙微粒灰尘等物质，会使其坏的胆固醇量升高，也会引起过量的发炎反应，此研究发表于5月份的Environmental Health Perspectives期刊。提醒气喘患者及易敏感的族群必需留意空气污染对身体造成的影响。
研究人员以12位患有气喘的病人进行测试，由研究结果显示：空气中每立方公尺的范围内，只要增加一毫克的微粒灰尘，受试者体内三甘油酯（triglyceride）含量就会增加5%，而三甘油酯数值过高，正是造成冠状动脉心脏病的高风险因子。而受试人员在曝露于高含量微粒灰尘时，其血液中的嗜伊红白血球（eosinophils）也会增加0.16%，这种白血球过度表现会造成过敏或气喘等症状，研究人员也发现到这些微粒灰尘会使受试者的心率变异（heart rate variability）降低3%，此现象代表受试者压力过大或者有心脏相关的疾病。
(资料来源 : Bio.com)
英文原文:
Coarse Particulate Matter in Air May Harm Hearts of Asthma Sufferers, UNC Study Finds
05/09/07 -- Breathing air containing coarse particulate matter such as road or construction dust may cause heart problems for asthma sufferers and other vulnerable populations, according to a new study led by the University of North Carolina at Chapel Hill School of Public Health.
The researchers found that in people with asthma, a small increase in coarse particulate matter in outdoor air raised bad cholesterol and increased the count of inflammation-linked white blood cells, among other changes.
"This research was all done with study participants just being outside and breathing outdoor air," said Dr. Karin Yeatts, research assistant professor of epidemiology at the UNC School of Public Health, a member of the UNC Center for Environmental Medicine, Asthma and Lung Biology, and the study's principal investigator. "Our results indicate that susceptible people really need to pay attention to air pollution warnings and stay inside when the air pollution is bad. This is particularly the case for people with asthma."
The study, published in the May 2007 issue of Environmental Health Perspectives, was a collaboration by researchers from the School of Public Health, the School of Medicine's Center for Environmental Medicine, Asthma and Lung Biology and the U.S. Environmental Protection Agency (EPA).
The team found that when adult asthma sufferers were exposed to a one microgram per cubic meter increase in coarse particulate matter in ambient air their triglyceride levels increased by nearly five percent. Elevated levels of triglycerides have been shown to increase one's risk of coronary heart disease. The amount of eosinophils in study participants' blood also increased by 0.16 percent after exposure to the higher levels of coarse particulate matter. Eosinophils are a type of white blood cell created by the human body to fight infections, allergies and diseases like asthma among other things. Finally, the same increase in coarse particulate matter resulted in a three percent decrease in a measure of heart rate variability, the variation of the beat-to-beat intervals of the heart. A healthy heart has wide heart rate variability, while decreased variability can indicate stress or cardiac disease.
Surprisingly, there was no relationship between coarse particulate matter and rescue medication use, asthma symptoms, lung function or airway inflammatory markers, Yeatts said. However, 10 of the 12 adult asthmatics in the study were taking anti-inflammatory controller medication for their disease, and nine of the 12 had mild disease. It is possible that anti-inflammatory treatment mitigated the effects in their airways, or that adults with asthma are less susceptible to the effects of coarse particulate matter.
Study participants consisted of 12 adults between the ages of 21 and 50 with persistent asthma. All lived within a 30-mile radius of the study's particulate matter monitor, located on the EPA Human Studies Facility at the Carolina campus. Each study participant took part in nine clinic visits: five the first week, and four spaced randomly over the subsequent six to 11 weeks. Data collection took place between September 2003 and July 2004. During the study, outdoor air levels of coarse particulate matter ranged between zero to 14.6 micrograms per cubic meter and did not exceed safety levels set by the EPA of 150 micrograms per cubic meter.
Other study authors include Lawrence Kupper, Alumni Distinguished Professor of biostatistics in the UNC School of Public Health; Dr. David Peden, director of the UNC Center for Environmental Medicine, Asthma and Lung Biology; Neil Alexis and Margaret Herbst, UNC Center for Environmental Medicine, Asthma and Lung Biology; Erik Svendsen, John Creason, James Scott, Lucas Neas, Robert Devlin and Ronald Williams of the EPA; and Dr. Wayne Cascio of Eastern Carolina University's Brody School of Medicine.
Source: University of North Carolina of Chapel Hill
