VOA慢速英语2015 美国研究空气污染与自闭症的关系

 

US Study Links Air Pollution to Autism 美国研究空气污染与自闭症的关系

From VOA Learning English, this is the Health & Lifestyle Report.

Autism spectrum¹ disorder² is a developmental disability. People with autism have trouble communicating and with social skills. The U.S. Centers for Disease Control and Prevention says the person also might repeat some behaviors and not want change in their daily activities. Some people with the condition need a lot of help. Others need less.  

CDC officials say autism affects one in every 68 children in the United States. More boys than girls are believed to have the condition. But the number of cases appears to be growing. It is unclear whether the growing number shows a real increase or comes from more knowledge about this disorder.

Symptoms of autism

Common signs of autism include trouble making eye contact and a delay in learning how to speak. Some people with severe autism never learn how to talk. Many people with autism also have difficulty understanding facial expressions and the feelings of others. They also have trouble making friends of the same age.

?Doctors have learned how to recognize autism, but much is still unknown about its causes.

Researchers at Harvard University have come closer to finding answers. They found that women exposed to the highest levels of fine particulate³ air pollution late in their pregnancies⁴ are two times more likely to give birth to a child with autism. The findings appeared in Environmental Health Perspectives -- a publication of the National Institute of Environmental Health Sciences.

Marc Weisskopf led the Harvard researchers. Mr. Weisskopf studies environmental conditions that cause sickness, developmental disabilities and deaths. He and his team studied women who were late in their pregnancies, shortly before they gave birth. In all, they examined medical records from all 50 U.S. states for about 116,000 mothers and their children.

The study found that the women who were around high levels of fine particulate matter air pollution were at highest risk of having an autistic child. The increased risk of these women was two times that of women who lived in areas with low levels of fine particulate pollution.

The researchers found that the timing⁵ of exposure to pollution was important. They found no increased risk of autism in children whose mothers were around high levels of pollution before becoming pregnant. And the study found air pollution does not seem to increase the risk of children developing autism after they are born.   

Marc Weisskopf says this finding does not prove there is a direct link between pollution and autism. But, he adds, it has ratcheted up, or increased, his team’s confidence that there is a relationship between the two.

“Finding an association like this that’s very specific in time rules out a lot of other possible explanations for that. So, it really ratchets up the strength of our confidence that we've got something really related to the air pollution here.”

What can pregnant women do?

Mr. Weisskopf says pregnant women should avoid air pollution as much as possible. But he warns that other things may increase the risk of autism spectrum disorder.

“You can avoid being in extremely polluted cities during pregnancy⁶ if possible. You can also choose to go running in a park rather than next to a street. But that said, I think also it’s very important to recognize that autism spectrum disorders⁷ is a very multi-factorial disorder. And there are lots of reasons why risk could be increased.”

Autism is believed to result from a combination of environmental and genetic⁸ factors.

Autism Speaks is an organization that helps families with autistic children. Paul Wang is head of medical research at Autism Speaks. He says the findings are very compelling. He notes that during the last three months of pregnancy, the brain of the fetus⁹ develops very quickly. He says the study does not change his group’s main suggestion: focus on treatment and educational therapies.

“For parents of children who have already been diagnosed, the focus should continue to be on treatment for them, on the behavioral, educational therapies that are available and that we know can help kids who are diagnosed with autism.”

For now, Marc Weisskopf says researchers are trying to identify the exact substances in air pollution that increase the risk of autism.

And that’s the Health and Lifestyle Report from VOA Learning English. I’m Anna Matteo.

Words in this Story

autism spectrum disorder - n. any of a group of developmental disorders (as autism and Asperger's syndrome) marked by impairments in the ability to communicate and interact socially and by the presence of repetitive behaviors or restricted interests

spectrum - n. a continuous sequence or range

fine particulate – n. very small solid material or liquid in the air

compelling – adj. capable of causing someone to believe or agree

ratchet up – v. to cause to move by steps or degrees -- usually used with up or down

confidence – n. the feeling of being certain that something will happen or that something is true

therapy – n. the treatment of physical or mental illnesses

1 spectrum   

n.谱，光谱，频谱；范围，幅度，系列

参考例句：

• This is a kind of atomic spectrum.这是一种原子光谱。
• We have known much of the constitution of the solar spectrum.关于太阳光谱的构成，我们已了解不少。

2 disorder   

n.紊乱，混乱；骚动，骚乱；疾病，失调

参考例句：

• When returning back,he discovered the room to be in disorder.回家后，他发现屋子里乱七八糟。
• It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。

3 particulate   

adj.微小的；n.微粒，粒子

参考例句：

• A special group was organized to dig up the particulate of the case.成立了一个专门小组来查明该案件的各个细节。
• Lungs retain relatively insoluble particulate material.肺脏内留有不溶解的颗粒物质。

4 pregnancies   

怀孕，妊娠( pregnancy的名词复数 )

参考例句：

• Since the wartime population needed replenishment, pregnancies were a good sign. 最后一桩倒不失为好现象，战时人口正该补充。
• She's had three pregnancies in four years. 她在四年中怀孕叁次。

5 timing   

n.时间安排，时间选择

参考例句：

• The timing of the meeting is not convenient.会议的时间安排不合适。
• The timing of our statement is very opportune.我们发表声明选择的时机很恰当。

6 pregnancy   

n.怀孕，怀孕期

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕早期常有恶心的现象。
• Smoking during pregnancy increases the risk of miscarriage.怀孕期吸烟会增加流产的危险。

7 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

8 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。

9 fetus   

n.胎，胎儿

参考例句：

• In the fetus,blood cells are formed in different sites at different ages.胎儿的血细胞在不同时期生成在不同的部位。
• No one knows why a fetus is not automatically rejected by the mother's immune system. 没有人知道为什么母亲的免疫系统不会自动排斥胎儿。