发病率（incidence）

发病率、患病率与病程三者的正确关系是（ ）。

A. 发病率=患病率×病程
B. 患病率=发病率×病程
C. 发病率=患病率+病程
D. 发病率=患病率-病程

评价疫苗免疫预防效果常用效果指数，其计算方法是

A.对照组发病率／接种组发病率
B.接种组发病率／对照组发病率
C.(对照组发病率-接种组发病率)／接种组发病率
D.(接种组发病率-对照组发病率)／接种组发病率
E.(对照组发病率-接种组发病率)／对照组发病率

共用题干
第二篇

Caffeine

Caffeine is probably the most widely used drug in the world.Humans have been consuming caffeine for
hundreds of years,primarily in the form of coffee,tea,and cocoa. Habitual coffee and tea drinkers had long
been observed to have a lower incidence of non-melanoma（黑色素瘤）skin cancers , although no one knew
why.A recent study found that caffeine affects skin cells damaged by ultraviolet radiation,a main cause of
skin cancer. Caffeine interferes with a protein that cancerous cells need to survive,leaving the damaged cells
to die before they become cancerous. Drinking caffeinated coffee has also been associated with a decreased
incidence of endometrial（子宫内膜的）cancer-that is , cancer of the cells lining the uterus. The strongest
effect appears to be in overweight women,who are at greatest risk for the disease.Researchers believe blood
sugar,fat cells,and estrogen（雌性激素）may play a role. Although the mechanism remains unknown,peo-
pie who drink more than two cups of coffee or tea a day reportedly have about half the risk of developing
chronic liver disease as those who drink less than one cup of coffee daily;caffeinated coffee has also been as-
sociated with lowered risk of cirrhosis（肝硬化）and liver cancer.
While many of caffeine's undesirable effects,such as elevated heart rate and blood pressure,are brief,
some short-term benefits,including pain relief,increased alertness,and increased physical endurance,have
also been attributed to caffeine.As a component of numerous over-the-counter diet pills and pain relievers,
caffeine increases their effectiveness and helps the body absorb them more quickly. By constricting（收缩）
blood vessels in the brain , it can alleviate headaches一even migraines（偏头痛）一and can help counter the
drowsiness（眩晕）caused by antihistamines（抗组胺药）.
Caffeine does not alter the need for sleep,but it does offer a temporary solution to fatigue for people who
need to stay alert. Research has shown that sleep-deprived individuals who consumed caffeine had improved
memory and reasoning abilities,at least in the short term. Studies of runners and cyclists have shown that
caffeine can improve their stamina一hence its addition to energy-boosting sports drinks.
People who consume a lot of caffeine regularly may develop temporary withdrawal symptoms,headache
being the most common,if they quit or cut back on it abruptly. Fortunately,these symptoms last only a day
or two in most cases.Individuals who are more sensitive to the stimulatory side effects of caffeine may want to
avoid it,but most doctors agree that the equivalent of three cups of coffee a day does not harm healthy
people.There is no medical basis to give up daily caffeine and many reasons to include a moderate amount in
one's diet.

Drinking coffee or tea may help_________.
A:lower the incidence of being overweight
B:lower the incidence of non-melanoma skin cancer
C:increase the incidence of endometrial cancer
D: increase the incidence of liver cancer

当某地某病的发病率和病程要相当长时间内保持稳定时，患病率、发病率和病程三者的关系是

A.发病率=患病率×病程
B.病程=发病率／患病率
C.患病率=发病率×病程
D.病程=患病率×发病率
E.患病率=发病率／病程

RR是（ ）。

A. 暴露组的发病率与对照组的发病率之差
B. 暴露组的发病率与对照组的发病率之比
C. 暴露组的发病率与暴露组的发病率之比
D. 非暴露组的发病率与暴露组的发病率之比

发病率、患病率和病程三者的正确关系是

A.患病率=发病率×病程
B.发病率=患病率×病程
C.发病率=患病率-病程
D.发病率=患病率+病程
E.病程=患病率×发病率

在比较不同地区发病率或死亡率时应注意使用

A.年龄别发病率、死亡率
B.性别发病率、死亡率
C.职业别发病率、死亡率
D.民族别发病率、死亡率
E.标化发病率、死亡率

Gun use has an additional tragic dimension when compared with tobacco, namely the high incidence of ____deaths, particularly among the young.

A.romantic
B.doomed
C.interesting
D.unintentional