美國國家衛生院11月27日首次提出研究證據顯示，身體質量指數（Body Mass Index / BMI）較高的肥胖人士，比苗條的人對煙霧的反應更為明顯。對許多人而言，短暫曝露於地表臭氧或煙霧，會引起肺功能減退的問題；不過這份報告，是首次針對肺功能減退與急性臭氧曝露的關聯性，研究體重因素在其中扮演的角色。
存在於平流層的臭氧層會阻隔太陽的紫外線，但地表的臭氧則不同，是由機汽車、工廠、發電廠等排放源釋出的污染物，經過光化學反應而產生於空氣中的。
研究人員分析了18-35歲年輕、健康而且不抽煙的男、女資料。他們測試身體質量指數 (根據個人的身高、體重來衡量肥胖的方法)是否會對急性臭氧曝露後的肺反應有所影響。這份研究於本月發表在《吸入性毒物》期刊。研究發現，隨著身體質量指數的增加，對臭氧的反應也隨之提高。
國家衛生院研究員研究員，同時也是這次研究的共同作者崙敦（Stephanie London, MD）表示：「長久以來，大家都了解暫時性曝露在臭氧中，會導致一些人的肺功能下降。最近，則開始有人對於為什麼有些人的肺功能降低幅度較大的問題產生興趣，原因可能是年紀、基因，甚至飲食也扮演重要的角色。」
一般而言，BMI越高，對臭氧的反應就越高。當受測者的身體肥胖程度也列入研究時，根據美國疾病管制局依BMI值所定義的肥胖發現，體重過輕的人，肺功能下降幅度最小，其次是正常體重的人，而BMI值大於25的過重人士，肺功能下降程度最大。
崙敦女士說：「這非常值得重視。這個結論是來自一份受測者多屬正常體重族群的研究報告。這表示，在一般的人口型態下，因為有較高比例的過重、甚至極度肥胖的族群時，這個影響會變的更加重要。」
The first evidence that fatter people with higher body mass index may have a greater reaction to smoggy air than leaner people was presented today by the National Institutes of Health. Short-term exposure to ground-level ozone, or smog, is known to cause a temporary drop in lung function in many people, but this is the first study in humans to look at whether body weight influences how much lung function drops after acute ozone exposure.
Distinct from the strataspheric ozone layer high in the atmosphere that protects from the Sun's rays, ground-level ozone is formed in the atmosphere in the presence of sunlight from other pollutants emitted from vehicles, factories, power plants and other sources.
Researchers analyzed data on young, healthy, non-smoking men and women 18–35 years of age. They tested to see if body mass index, BMI, a measure of fatness based on an individual's height and weight, had an effect on lung response to acute ozone exposure.
The study published this month in the journal "Inhalation Toxicology" found that ozone response was greater with increasing body mass index.
"It has been known for a long time that in response to short-term exposure to ozone lung function tends to temporarily drop in many people. There has recently been interest in why some people's lung function drops more than others - age and perhaps genetics, as well as diet may play a role," said NIEHS researcher and co-author Stephanie London, MD.
In general, the higher the BMI, the greater the ozone response.
When subjects were put into categories of body fatness defined by the U.S. Centers for Disease Control based on their BMI, the drops in lung function, were lowest in underweight people, greater in normal weight people, and greatest in overweight individuals with BMI indexes greater than 25.
"It's notable that these results came out of a study that was done in a population of predominantly normal weight individuals," said London. "This suggests that these effects may be even more important in the general population where there are large proportions of overweight and obese individuals."
全文及圖片詳見：ENS
