2006年VOA标准英语-Study: Smokers' Race, Ethnicity Affect Lun

By David McAlary
Washington
25 January 2006
 
  
  
When it comes to lung cancer rates among smokers¹, scientists say race and ethnicity matter.  A new study reports significant differences in the rates among smokers from five U.S. ethnic² and racial groups, with the highest among blacks and native Hawaiians.

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The incidence of lung cancer in the United States is highest among blacks and Polynesians and lowest among Japanese-Americans and Hispanics, with whites in between. Some people have thought that differences in smoking behavior might account for this disparity. But a study in the New England Journal of Medicine shows that these relative disease rates remain even when the number of cigarettes smoked is comparable.

Researchers from the Universities of Southern California and Hawaii examined lung cancer rates among 184,000 American men and women of European, African, Japanese, Hispanic ancestry³ and native Hawaiians. Their average age was 60.

They found that of those who smoked 20 or fewer cigarettes a day, the blacks and native Hawaiians had the greatest risk of lung cancer. Whites had about half the risk of these two groups, while Japanese-Americans and Hispanics had one-fifth to two-fifths the risk respectively.

The reason why is a mystery.

"The factors that explain these differences we don't know about," says Christopher Haiman of the University of Southern California and lead author of the study.

  
  
He adds that differences in lung cancer risk among racial and ethnic groups cannot be explained by diet, occupation, socioeconomic status or other known or suspected factors. He suggests one reason might be genetic⁴ differences in how their bodies process the cancer-causing chemicals in tobacco.

"There could be variation in how different populations metabolize nicotine⁵, which could influence smoking behaviors such as the intensity⁶ of smoking, the depth and frequency of inhalation, and therefore influence the uptake of carcinogens," he notes.  "We know there are genes⁷ that are shared across populations, but they have different frequencies which could make some populations more susceptible⁸ to the effects of tobacco smoke. But it's most likely due to combinations of unmeasured environmental factors as well as genetic differences."

The research shows that racial and ethnic differences in lung cancer risk disappeared among heavy smokers in the study. Their chance of getting the disease was similar if they smoked 30 or more cigarettes a day.

Whether the findings can be applied⁹ directly to ancestral populations in Africa, Europe, and Japan is unclear. American racial groups are a blend of genetic heritages. According to one expert on disease distribution among populations, Neil Risch of the University of California at San Francisco, black Americans average about 20 percent European ancestry. U.S. Hispanics are even more complex, tracing their lineage to Europe, the Americas, and Africa.

"We have somewhat different groups here than internationally in terms of the ethnic makeup¹⁰ of the United States," says Mr. Risch.

But Risch says from the policymaking point of view, the ethnic and racial differences in lung cancer are unimportant.

"From the public health perspective, these findings don't really matter, because it shows that the ethnic differences pretty much disappear when you eliminate smoking," he explains.  "So from the perspective of public health, it may not be that helpful."

But both Risch and study author Christopher Haiman say such findings could be useful for the information they might provide about the mechanisms¹¹ by which cancer causing compounds influence the risk of disease.

1 smokers   

吸烟者( smoker的名词复数 )

参考例句：

• Many smokers who are chemically addicted to nicotine cannot cut down easily. 许多有尼古丁瘾的抽烟人不容易把烟戒掉。
• Chain smokers don't care about the dangers of smoking. 烟鬼似乎不在乎吸烟带来的种种危害。

2 ethnic   

adj.人种的，种族的，异教徒的

参考例句：

• This music would sound more ethnic if you played it in steel drums.如果你用钢鼓演奏，这首乐曲将更具民族特色。
• The plan is likely only to aggravate ethnic frictions.这一方案很有可能只会加剧种族冲突。

3 ancestry   

n.祖先，家世

参考例句：

• Their ancestry settled the land in 1856.他们的祖辈1856年在这块土地上定居下来。
• He is an American of French ancestry.他是法国血统的美国人。

4 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

5 nicotine   

n.(化)尼古丁，烟碱

参考例句：

• Many smokers who are chemically addicted to nicotine cannot cut down easily.许多有尼古丁瘾的抽烟人不容易把烟戒掉。
• Many smokers who are chemically addicted to nicotine cannot cut down easily.许多有尼古丁瘾的抽烟人不容易把烟戒掉。

6 intensity   

n.强烈，剧烈；强度；烈度

参考例句：

• I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
• The strike is growing in intensity.罢工日益加剧。

7 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

8 susceptible   

adj.过敏的，敏感的；易动感情的，易受感动的

参考例句：

• Children are more susceptible than adults.孩子比成人易受感动。
• We are all susceptible to advertising.我们都易受广告的影响。

9 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

10 makeup   

n.组织；性格；化装品

参考例句：

• Those who failed the exam take a makeup exam.这次考试不及格的人必须参加补考。
• Do you think her beauty could makeup for her stupidity?你认为她的美丽能弥补她的愚蠢吗？

11 mechanisms   

n.机械( mechanism的名词复数 )；机械装置；[生物学] 机制；机械作用

参考例句：

• The research will provide direct insight into molecular mechanisms. 这项研究将使人能够直接地了解分子的机理。 来自《简明英汉词典》
• He explained how the two mechanisms worked. 他解释这两台机械装置是如何工作的。 来自《简明英汉词典》