VOA慢速英语-SCIENCE IN THE NEWS - Ten Percent of Healthy People

VOICE ONE:

This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty¹.

VOICE TWO:

And I'm Faith Lapidus. This week, we will tell about a brain injury known as silent stroke. We will also tell about melanoma -- the most deadly form of skin cancer. And, we will tell you about the healthful effects of vitamin D.

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VOICE ONE:
　
Magnetic resonance² imaging tests are used to inspect for damaged brain tissue and signs of stroke

Stroke is a serious problem that can lead to death. Usually the warning signs appear suddenly. But a recent study found that seemingly healthy middle-aged³ people could suffer a stroke without immediately knowing it. The finding was reported in "Stroke: Journal of the American Heart Association."

The study involved about two thousand people. They were the children of men and women who took part in the Framingham Heart Study. The Framingham Heart Study began sixty years ago in Framingham, a town in the American state of Massachusetts. Much of what doctors know about heart disease has resulted from this research project.

VOICE TWO:

The average age of men and women in the new study was sixty-two years. The group's members received medical examinations every four to eight years. They were given magnetic resonance imaging tests to inspect for damaged brain tissue and signs of stroke.

The imaging tests showed that nearly eleven percent of those with no sign of stroke had suffered a silent cerebral⁴ infarction, or silent stroke. Silent strokes are brain injuries likely caused by a blockage⁵ that limits blood to the brain.

Eighty-four percent of those who suffered silent strokes had a single wound, or lesion, in the brain. This kind of damage can lead to increased risk of future strokes and long-term memory loss.

VOICE ONE:

For the first time, the researchers found a link between silent stroke and the condition atrial fibrillation. Atrial fibrillation is the most common cause of unusual heartbeat in older adults.

Sudha Seshadri works at the Boston University School of Medicine. She says atrial fibrillation increased the risk of suffering a stroke more than two times. High blood pressure and systolic blood pressure were also linked to an increased risk of silent stroke. Blood pressure readings are usually given in two numbers. The upper number is systolic blood pressure.

VOICE TWO:

Doctor Seshadri says the findings show the need for early testing and treatment of conditions that could lead to heart disease in middle-aged people. Experts say nothing special needs to be done to reduce the risk of silent stroke. But they are urging people to watch for risk factors. They include atrial fibrilation, high blood pressure, heart disease, diabetes⁶ and cigarette smoking.

The American Stroke Association says people who think they are having a stroke should seek emergency medical help. The warning signs include sudden weakness, especially on one side of the body, and difficulty speaking or understanding. Other warning signs are trouble seeing in one or both eyes, trouble walking, loss of balance and severe head pain.

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VOICE ONE:

An American study shows that increasing numbers of young women are developing melanoma, the most deadly form of skin cancer. The study did not identify causes of the increase. However, the lead researcher says it could be the result of young women seeking to make their skin darker.

The American Cancer Society says about sixty-two thousand cases of melanoma are found each year in the United States. The disease will kill more than eight thousand four hundred Americans this year.

The biggest risk for developing melanoma is ultraviolet radiation. However, genetics could also be important. People with light or fair skin are most at risk. Yet melanoma affects people of all races and skin colors.

VOICE TWO:

Results of the new study were reported last month in the Journal of Investigative Dermatology. The increase in melanoma cases is nothing new. Other studies have shown the rate of new cases increasing in the general population. But federal researchers did not know about the sharp increase among young women.

Mark Purdue of the National Cancer Institute led the study. His team examined rates of melanoma for a thirty-year period -- from nineteen seventy-three to two thousand four. They found more than twenty thousand melanoma cases in Americans between the ages of fifteen and thirty-nine years.

The researchers say they found that the rate among young women rose fifty percent since nineteen eighty. For men of the same age, however, the rate stayed the same.

VOICE ONE:

One reason for the rise in cases could be an increase in early discovery of the disease. But the researchers believe that is not the only reason because more serious forms of the cancer are being found.

Some experts say the study's results could be a sign of an even greater problem in the future. This is because melanoma can develop over years and become deadly later in life. The number of older adults with the disease has been increasing for many years.

VOICE TWO:

Mark Purdue says the findings suggest that public education campaigns about the dangers of skin cancer do not seem to be helping⁷. He believes the increase may be connected to women spending more time under the sun and in tanning salon⁸ beds. Tanning beds produce ultraviolet radiation that can damage the skin.

The tanning salon industry disputes the idea that its treatments are to blame for the rising melanoma rates.

People can reduce their risk of developing the disease by avoiding the sun when it is strongest. Wearing protective clothing and sunblock products can also reduce the risk.

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VOICE ONE:

Vitamin D helps bones and muscles grow strong and healthy. Low levels of vitamin D can lead to problems such as rickets⁹, a disorder¹⁰ mainly found in children. Osteoporosis, the thinning of bone, is a common problem as people, especially women, get older. But more and more research is suggesting that vitamin D might also help prevent many diseases.

VOICE TWO:

The easiest way to get vitamin D is from sunlight. The sun's ultraviolet radiation reacts with skin cells to produce vitamin D. But many people worry about getting skin cancer and skin damage from the sun. As a result, they cover their skin, wear sunblock products or stay out of the sun.

Also, darker skinned people produce less vitamin D than lighter¹¹ skinned people. Production also decreases in older people and those living in northern areas that get less sunlight.

Not many foods naturally contain vitamin D. Foods high in this vitamin include fish liver oils and oily fish such as salmon¹², tuna and mackerel.

VOICE ONE:

Boston University researchers reported last year that farmed salmon had only about one-fourth as much vitamin D as wild salmon.

Small amounts of the vitamin are found in beef liver, cheese and egg yolks. And some people take dietary supplements containing it. But most of the vitamin D in the American diet comes from foods with D added, like milk.

In nineteen ninety-seven, the United States Institute of Medicine established levels for how much vitamin D healthy people need. It set the daily amount at two hundred international units from birth through age fifty. It set the level at four hundred I.U.s through age seventy, and six hundred for age seventy-one and over.

But some groups say these amounts are not high enough. They are hoping that the new study findings will lead to new suggestions.

VOICE TWO:

Research in the past several years has shown that low levels of vitamin D may increase the risk of heart attacks in men and deaths from some cancers. Other studies have shown that people with rheumatic diseases often have low levels of vitamin D.

More doctors are now having their patients tested for their vitamin D levels. But as research continues, some experts worry that if people take too much vitamin D, it might act as a poison. Also, skin doctors warn people to be careful with sun exposure because of the risk of skin cancer.

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VOICE ONE:

This SCIENCE IN THE NEWS program was written by Lawan Davis, Caty Weaver¹³ and Brianna Blake, who also was our producer. I'm Bob Doughty.

VOICE TWO:

And I'm Faith Lapidus. Read and listen to our programs at voaspecialenglish.com. Join us at this time next week for more news about science on the Voice of America.

 

1 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

2 resonance   

n.洪亮；共鸣；共振

参考例句：

• Playing the piano sets up resonance in those glass ornaments.一弹钢琴那些玻璃饰物就会产生共振。
• The areas under the two resonance envelopes are unequal.两个共振峰下面的面积是不相等的。

3 middle-aged   

adj.中年的

参考例句：

• I noticed two middle-aged passengers.我注意到两个中年乘客。
• The new skin balm was welcome by middle-aged women.这种新护肤香膏受到了中年妇女的欢迎。

4 cerebral   

adj.脑的，大脑的；有智力的，理智型的

参考例句：

• Your left cerebral hemisphere controls the right-hand side of your body.你的左半脑控制身体的右半身。
• He is a precise,methodical,cerebral man who carefully chooses his words.他是一个一丝不苟、有条理和理智的人，措辞谨慎。

5 blockage   

n.障碍物；封锁

参考例句：

• The logical treatment is to remove this blockage.合理的治疗方法就是清除堵塞物。
• If the blockage worked,they could retreat with dignity.如果封锁发生作用，他们可以体面地撤退。

6 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

7 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

8 salon   

n.[法]沙龙；客厅；营业性的高级服务室

参考例句：

• Do you go to the hairdresser or beauty salon more than twice a week?你每周去美容院或美容沙龙多过两次吗？
• You can hear a lot of dirt at a salon.你在沙龙上会听到很多流言蜚语。

9 rickets   

n.软骨病，佝偻病，驼背

参考例句：

• A diet deficient in vitamin D may cause the disease rickets.缺少维生素D的饮食可能导致软骨病。
• It also appears to do more than just protect against rickets.除了防止软骨病，它还有更多的功能。

10 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。

11 lighter   

n.打火机，点火器；驳船；v.用驳船运送；light的比较级

参考例句：

• The portrait was touched up so as to make it lighter.这张画经过润色，色调明朗了一些。
• The lighter works off the car battery.引燃器利用汽车蓄电池打火。

12 salmon   

n.鲑，大马哈鱼，橙红色的

参考例句：

• We saw a salmon jumping in the waterfall there.我们看见一条大马哈鱼在那边瀑布中跳跃。
• Do you have any fresh salmon in at the moment?现在有新鲜大马哈鱼卖吗？

13 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。