职称英语卫生类b级|2017年职称英语卫生类A级阅读复习讲义(7)

Life Expectancy in the Last Hundred Years

上世纪人类平均寿命的变化

　　A hundred years ago,life expectancy in developed countries was about 47: in the early 21st century, men in the United States and the United Kingdom can expect to live to about 74. Women to about 80, and these ages are rising all the time. What has brought about these changes? When we look at the life span of people l00 years ago, we need to look at the greatest killers of the time. In the early 20th century, these were the acute and often high infectious diseases such as smallpox. Many children died very young from these diseases and others, and the weak and elderly were always at risk.

　　n the developed world these diseases are far lessdeadly today, and in some cases have almost disappeared. A number of factor shave led to this: improvements in sanitation and hygiene, the discovery and use of antibiotics, which make bacterial diseases much less dangerous, and vaccinations against common diseases. In addition, people's general health has improved with improvements in our general environment: cleaner air, better means of preserving food,better and warmer housing，and better understanding of nutrition.

　　Genetically,we should all be able to live to about 85 but while people do live longer today, there are still some big killers around that are preventing US from consistently reaching that age. The problems that affect people today are the more chronic illnesses, such as heart disease and strokes, and those spread by viruses, such as influenza and AIDS l. Of course, cancer is a huge killer as well. In most cases these diseases affect older people, but there are worrying trends in the developed world with problems such as obesity leading to more heart disease and illnesses such as diabetes at younger ages.

　　The killers today can be classed as "lifestyle diseases",which means that it may be possible to halt their progress.

　　一百年前，发达国家的人口平均寿命约为47岁，到21世纪初，美英两国男性平均寿命为74岁，女性约为80岁，人们的平均寿命一直在延长。是什么造成这样的变化呢?在研究100年前人类的寿命时，我们需要注意当时的一些不治之症。早在20世纪初期，这些不治之症经常是像天花之类的急性的高传染病。许多儿童因此夭折(也有其他原因)，年迈体弱的人也总面临着他们的威胁。

　　如今，这些疾病在发达国家已经远不能致命。这一变化归于许多因素，比如：环境及个人卫生的改善、抗生素的发现及使用(抗生素大大降低了细菌病的危险)以及常见疾病预防疫苗的接种。除此之外，更洁净的空气、更好的食物保鲜方法、更舒适温暖的屋子还有对营养的进一步认识，这些总的环境的改善也促进了人们的整体健康。

　　从基因角度看，人都能活到85岁。但尽管现在人们寿命确实比以前长了，仍然有一些疾病使得我们不能都活到那个岁数。现在困扰人们的是像心脏病、中风那些更为慢性的疾病，还有像流行性感冒和艾滋病那些通过病毒传染的疾病。当然，癌症也是一大杀手。上述疾病大多影响着老年人，但令人担忧的问题在发达国家日趋明显，如：肥胖症产生更多心脏病、糖尿病等其他疾病患者群渐成年轻化。

　　人们如果把这些疾病归为“生活方式疾病”，这意味着人们生活方式的改善有可能阻止它们的进一步发展。

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