2006年VOA标准英语-Study: Iron Supplements Can Make Children

By David McAlary
Washington
13 January 2006
 
  
  
A new study says United Nations health guidelines recommending iron supplements for anemic children could be dangerous in certain circumstances. Researchers from the United States and Zanzibar say that in areas where malaria¹ is intense, iron supplements can increase the risk of severe illness and death.

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U.N. data show that about 75 percent of East African children under five suffer anemia² caused by iron deficiency. In areas where anemia is common, international guidelines call for iron and folic acid supplements for all children under two.

But a study in the medical journal Lancet shows that in places where anemia and malaria coincide, the iron supplements result in increased hospitalizations and death.

Johns Hopkins University physician Robert Black led the study of more than 24,000 children aged³ one month to three years in Pemba, Zanzibar, an area of high malaria transmission.

"For a number of years, there has been a concern about giving iron to populations, particularly children, that have malaria, and this seems to have been borne out in this study," said Mr. Black.

Black's team assigned the children to randomly⁴ receive various combinations of iron, folic acid, and zinc⁵, or no supplements at all. They stopped the study early for groups getting the iron and folic acid combination because it made some children's malaria worse. Overall, children getting those minerals had a 12 percent higher risk of hospitalization for severe disease or death than those receiving no supplements.

In contrast, a companion study by Black and his colleagues in Nepal, where malaria transmission is low, shows that the supplements did not increase death and sickness among children.

The Johns Hopkins University doctor says the Zanzibar research shows that the problem seems to be with iron, not folic acid, but the biological explanation is unclear.

"It appears that there is an adverse⁶ affect of giving iron in this setting, perhaps related to the stimulation⁷ of the bone marrow⁸ to produce red blood cells that are then more readily infected with the malaria parasite," he said.  "Or perhaps there is a direct toxic⁹ effect of the iron that has been hypothesized, but the exact mechanism¹⁰ has not been worked out."

The Zanzibar study shows that iron supplements did help some children, but only those who were anemic in the first place. As a result, the researchers recommend revising international guidelines to avoid blanket iron supplementation in places where malaria is endemic.

"One possibility is to provide iron only when there is adequate malaria control or possibly iron and antimalarial drugs simultaneously¹¹ so that the malaria is controlled when iron is presented to the child," he noted¹².  "A second possibility is that there could be screening for anemia so that only children with iron deficiency anemia would be given iron."

A Lancet commentary accompanying the Zanzibar and Nepal studies calls them a significant advance. But its authors say they represent only the extreme ends of the malaria spectrum¹³ and do not yet provide adequate evidence for global policy.  The authors, from the Kenya Medical Research Institute in Nairobi, are calling for more large iron supplementation trials in areas of different levels of malaria transmission.

1 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

2 anemia   

n.贫血，贫血症

参考例句：

• The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。
• I was put on iron tablets for my anemia.我曾因贫血吃补铁药片。

3 aged   

adj.年老的，陈年的

参考例句：

• He had put on weight and aged a little.他胖了，也老点了。
• He is aged,but his memory is still good.他已年老，然而记忆力还好。

4 randomly   

adv.随便地，未加计划地

参考例句：

• Within the hot gas chamber, molecules are moving randomly in all directions. 在灼热的气体燃烧室内，分子在各个方向上作无规运动。 来自辞典例句
• Transformed cells are loosely attached, rounded and randomly oriented. 转化细胞则不大贴壁、圆缩并呈杂乱分布。 来自辞典例句

5 zinc   

n.锌；vt.在...上镀锌

参考例句：

• Brass is formed by the fusion of copper and zinc.黄铜是通过铜和锌的熔合而成的。
• Zinc is used to protect other metals from corrosion.锌被用来保护其他金属不受腐蚀。

6 adverse   

adj.不利的；有害的；敌对的，不友好的

参考例句：

• He is adverse to going abroad.他反对出国。
• The improper use of medicine could lead to severe adverse reactions.用药不当会产生严重的不良反应。

7 stimulation   

n.刺激，激励，鼓舞

参考例句：

• The playgroup provides plenty of stimulation for the children.幼儿游戏组给孩子很多启发。
• You don't get any intellectual stimulation in this job.你不能从这份工作中获得任何智力启发。

8 marrow   

n.骨髓；精华；活力

参考例句：

• It was so cold that he felt frozen to the marrow. 天气太冷了，他感到寒冷刺骨。
• He was tired to the marrow of his bones.他真是累得筋疲力尽了。

9 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

10 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

11 simultaneously   

adv.同时发生地，同时进行地

参考例句：

• The radar beam can track a number of targets almost simultaneously.雷达波几乎可以同时追着多个目标。
• The Windows allow a computer user to execute multiple programs simultaneously.Windows允许计算机用户同时运行多个程序。

12 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

13 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。