VOA标准英语2009年-Research Shows Appetite Hormone May He

Experts predict a global epidemic¹ of Alzheimer's disease as the world's population ages. Their focus is now on a fat hormone² that may indicate who is more likely to get Alzheimer's or other forms of dementia.

By 2050, the number of people with Alzheimer's is expected to quadruple. In just 40 years, experts say it will increase from one in every 350 people to one in 85. Many will need high levels of care.

Researchers say that dramatically increasing global life expectancy³ makes it imperative⁴ to find solutions that prevent, delay, slow, and treat Alzheimer's disease and related dementias.

"All our brains shrink a little as we grow older, but in some people it shrinks more and [in] some it shrinks less," said Dr. Sudha Seshadri, one of the researchers at Boston University who co-authored a new study on dementia.  "And if it shrinks more, it puts you at higher risk of developing dementia and Alzheimer's."

The study focuses on leptin, a hormone that helps control appetite. Researchers discovered that people whose brains have higher levels of leptin are less likely to suffer from Alzheimer's or other forms of dementia.

The study looked at leptin levels in more than 700 elderly adults who did not have dementia. Eight years later, 200 of the participants had brain scans. The researchers found a link between leptin and dementia.

"People in the highest quartile of leptin had only a six percent risk of developing dementia over this time, over 12 years, whereas people in the lowest quartile had a 25 percent risk of developing dementia," said Dr. Seshadri

Researchers also looked at brain size as these participants aged⁵.

"We also looked at the part of the brain called the hippocampus which is very important for forming the sort of memories we make everyday, you know, when you have to remember a pin number or you have to remember how to get somewhere, and the hippocampus, if it's a good size that means you are less likely to develop Alzheimer's," Dr. Seshadri said.

The report is in The Journal of the American Medical Association.

The scientists say if their work is confirmed, it could lead to further research on how lifestyle choices figure in the prevention and treatment of age-related decline and diseases such as Alzheimer's.
 

1 epidemic   

n.流行病；盛行；adj.流行性的，流传极广的

参考例句：

• That kind of epidemic disease has long been stamped out.那种传染病早已绝迹。
• The authorities tried to localise the epidemic.当局试图把流行病限制在局部范围。

2 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

3 expectancy   

n.期望，预期，（根据概率统计求得）预期数额

参考例句：

• Japanese people have a very high life expectancy.日本人的平均寿命非常长。
• The atomosphere of tense expectancy sobered everyone.这种期望的紧张气氛使每个人变得严肃起来。

4 imperative   

n.命令，需要；规则；祈使语气；adj.强制的；紧急的

参考例句：

• He always speaks in an imperative tone of voice.他老是用命令的口吻讲话。
• The events of the past few days make it imperative for her to act.过去这几天发生的事迫使她不得不立即行动。

5 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。