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Even though about 25% of adults think that
有多达25%的成人认为
they have an allergy,
他们有食物过敏症
only 1 to 2% of adults and 5% of children
但是只有1%到2%的成人和5%的儿童
are truly affected.
确实有食物过敏症
Determination of the exact prevalence of food allergies
对食物过敏症患病率的测定
is complicated because there is considerable variation
非常复杂，因为需要收集的
in data collection.
数据非常多
Reports are based on self-reported questionnaires,
通常的报告包括自诉问卷
physician assessment, skin tests and/or IgE levels
医师评估，皮肤测试和/或者
that are confirmed by double-blind placebo
由双盲安慰剂控制的
controlled challenges.
IgE水平测试
However many do not distinguish between IgE
但是这其中的很多手段对IgE介导型
and non-IgE mediated responses.
和非IgE介导型反应无法进行区分
In general food allergy manifests most commonly
总体说来，食物过敏
in infancy peaking at 1 year of age
在不超过1周岁的婴儿中最为常见
and diminishing by age three.
一般到3岁的时候会消失
Infants are more susceptible to food allergies
婴儿更容易受食物过敏的影响
because they have a decreased number of enzymes
因为他们体内存在的可以
to break down proteins, low antibody levels,
分解蛋白质的酶数量较少，抗体水平低
relatively low pH and an immature gut barrier.
pH值较低以及肠道屏障不成熟
This chart from the Center of Disease Control
这张图表来自疾病控制和预防中心
and Prevention shows the growing trend of
显示的是对食物过敏报告的发展趋势
reported allergies from an average of 2615 between,
1928到2000年年均报告2615例
each year, 1928 and 2000 to over 9500 each year
从2004到2006年间
between 2004 and 2006.
年均报告9500例
It is not well understood
目前这种增长趋势的原因
why this increase has occurred.
尚无法解释
There are several hypotheses about
对于食物过敏症报告率的
the rising prevalence of food allergy.
增加的原因存在几个假设
Development of an allergy depends on
过敏反应的发生发展取决于
the structure of the protein, the dose of the antigen
蛋白质的组成形式，抗原的剂量
and the genetic susceptibility of the host.
以及人体的遗传易感性
Oral exposure to low doses of a protein may induce
口腔接触低剂量的蛋白质可能会
sensitization whereas high doses may
引起过敏，而高剂量
result in tolerance.
则可能会导致耐受性
This is pertinent to those who encounter accidental
这与无意间
exposures to the allergens in protein
接触到了蛋白质抗原有关
as it may be potentially harmful.
会有潜在的危害性
Conversely non-oral exposure may be
相反，非通过口腔接触
a primary risk factor as damaged skin may
蛋白质抗原可能更有风险
allow increased exposure before tolerance has been
比如通过受伤的皮肤大量接触
developed through oral ingestion.
而这个时候耐受性还没有形成
Food allergy to peanuts is the most common
对花生的食物过敏是最常见的
but other foods such as milk, egg, tree nuts, fish,
但是对于一些人来说，牛奶，蛋类，干果
shellfish, wheat and soy are also known
鱼类，贝类，小麦和大豆也可能会
to cause allergic reactions in some people.
引发过敏性反应
The majority of this presentation will focus on
这里我们主要关注的是
the peanut allergy.
花生过敏
It has been shown that many individuals
研究结果已经表明，有很多人
may have developed sensitization to peanuts
对花生都会出现敏感反应
but only 95% of those are diagnosed
但是只有95%会被
as clinically allergic.
临床诊断为食物过敏
Peanut allergy has attracted the most attention
由于花生的普遍性
because it is relatively common,
以及过敏反应的长期性和严重性
typically permanent and often severe.
花生过敏最为引人关注
It has significantly increased globally
在过去的十年中，花生过敏在全球范围内
in the past decade and is now 2 to 3 times
都出现了增长趋势，现在花生过敏的
more common than other food allergies.
普遍性已经是其他食物过敏的2到3倍
One common cause attributed to the increase
这其中的一个原因
in this particular allergy and for the rise
从总体上
in allergy incidences in general
来说
is the hygiene hypothesis.
是卫生假设
The hygiene hypothesis originated from
这种假设起源于
epidemiological observations relating exposure
流行病学中与过敏风险较小的
to other children to a reduced risk of allergy.
儿童的接触的观察
It has been hypothesized that our society's knack
内容为假设我们的社会
for cleanliness has attributed to the rise
越来越干净
in food allergies.
这就是食物过敏症增多的原因
Studies from many countries show
很多国家的研究表明
that early exposure of viral infections may
如果一个人很早就受到病毒性感染
produce a proactive effect against the sensitization
那么他可以形成对抗原敏感的对抗能力
of allergens and others conclude that
另一项研究表明
babies born into families with many children
在有多个孩子的家庭中出生的孩子
are less inclined to develop allergies.
更不易出现过敏
