One in five Americans has hearing loss: study

 　　WASHINGTON, Nov. 14 (Xinhua) -- Nearly a fifth of all Americans 12 years or older have hearing loss so severe that it may make communication difficult, according to a new study led by Johns Hopkins University researchers and published Monday in the Archives of Internal Medicine.

　　The findings, thought to be the first nationally representative estimate of hearing loss, suggest that many more people than previously¹ thought are affected² by this condition.

　　Study leader Frank Lin, an assistant professor, and his colleagues used data from the National Health and Nutritional³ Examination Surveys (NHANES), a research program that has periodically gathered health data from thousands of Americans since 1971. The researchers analyzed⁴ data from all participants age 12 and over whose hearing was tested during NHANES examinations from 2001 to 2008. Unlike previous estimates, NHANES includes men and women of all races and ages, from cities scattered⁵ across the country, so it's thought to statistically⁶ mimic⁷ the population of the Untied⁸ States.

　　Using the World Health Organization's definition for hearing loss (not being able to hear sounds of 25 decibels⁹ or less in the speech frequencies), the researchers found that overall, about 30 million Americans, or 12.7 percent of the population, had hearing loss in both ears. That number jumps to about 48 million, or 20.3 percent, for people who have hearing loss in at least one ear. These numbers far surpass previous estimates of 21 to 29 million.

　　Hearing loss prevalence nearly doubled with every age decade, with women and blacks being significantly less likely to have hearing loss at any age. Lin and his colleagues aren't sure why these groups appear to be protected. However, he notes that the female hormone¹⁰ estrogen, as well as the melanin pigment¹¹ in darker skin, could have a protective effect on the inner ear.

1 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

2 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

3 nutritional   

adj.营养的，滋养的

参考例句：

• A diet lacking in nutritional value will not keep a person healthy.缺乏营养价值的饮食不能维持人的健康。
• The labels on food products give a lot of information about their nutritional content.食品上的标签提供很多关于营养成分的信息。

4 analyzed   

v.分析( analyze的过去式和过去分词 )；分解；解释；对…进行心理分析

参考例句：

• The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
• The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程，因为对他来说，爱是个不可分析的迷。 来自《简明英汉词典》

5 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

6 statistically   

ad.根据统计数据来看，从统计学的观点来看

参考例句：

• The sample of building permits is larger and therefore, statistically satisfying. 建筑许可数的样本比较大，所以统计数据更令人满意。
• The results of each test would have to be statistically independent. 每次试验的结果在统计上必须是独立的。

7 mimic   

v.模仿，戏弄；n.模仿他人言行的人

参考例句：

• A parrot can mimic a person's voice.鹦鹉能学人的声音。
• He used to mimic speech peculiarities of another.他过去总是模仿别人讲话的特点。

8 untied   

松开，解开( untie的过去式和过去分词 )； 解除，使自由； 解决

参考例句：

• Once untied, we common people are able to conquer nature, too. 只要团结起来，我们老百姓也能移山倒海。
• He untied the ropes. 他解开了绳子。

9 decibels   

n.分贝( decibel的名词复数 )

参考例句：

• The typical lawn mower makes about 90 decibels of noise. 典型的割草机发出的声响约为90分贝。 来自《简明英汉词典》
• A normal conversation reaches 55 decibels. 普通的谈话即可达55分贝。 来自《简明英汉词典》

10 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。

11 pigment   

n.天然色素，干粉颜料

参考例句：

• The Romans used natural pigments on their fabrics and walls.古罗马人在织物和墙壁上使用天然颜料。
• Who thought he might know what the skin pigment phenomenon meant.他自认为可能知道皮肤色素出现这种现象到底是怎么回事。