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实习一 疾病频率测量的常用指标
五 练习题
（一）名词解释：答案见课本P16-22 （二）单选题
1 B 2 B 3 E 4 C 5 B （三）论述题：答案见课本P17-18
实习二 疾病分布
五 练习题
（一）名词解释：答案见课本P16-22 （二）单选题 1 B 2 C （三）多选题
1 ABD 2 ABD 3 ABDE 4 ABCD 5 BCDE （四）论述题：
1. 答案见课本P26 2. 答案见课本P33-34 3. 答案见课本P35-36 4. 答案见课本P28
实习三 现况研究
五 练习题 一 单选题
1.C 2.B 3.E 4.E 5.C 6.E 7.D 8.E 二、多选题
1. ABCDE 2. ABDE 3. ABC 4. ABCDE 5. ABD 6. ABCDE 三 简答题
1. 现况研究的目的：(1)掌握目标群体中疾病的患病率及其分布状态；（2）提供疾病的致病因素的线索；（3）确定高危人群；（4）对疾病监测、预防接种效果及其他资料质量的评价。
现况研究的特点：(1)开始时一般不设对照组；（2）研究某特定时点或时期内某一群体中暴露和疾病的联系；（3）现况研究揭示暴露与疾病之间的统计学联系，仅为建立因果关系提供线索，是分析性研究的基础，不能以此作因果推论；而对不会发生改变的暴露因素，可以作因果推论；（4）用现在的暴露来替代或估计过
去情况的条件；（5）现况研究重复进行可以获得发病率资料。
2. 现况研究常用的抽样方法有：(1)单纯随机抽样；（2）系统抽样；（3）分层抽样；（4）整群抽样；（5）多级抽样。
3.决定现况研究的样本大小的因素来自多方面，但主要是：①预期的患病率，如现患率越靠近50％，样本含量就越小；反之，则要大些。②对调查结果精确性的要求，即允许误差越大，则所需样本就越小。 四 论述题
1. 现况研究的常见偏倚有
（1）选择偏倚：①选择性偏倚；②无应答偏倚；③幸存者偏倚。 （2）信息偏倚：①调查对象引起的偏倚；②调查员偏倚；③测量偏倚。 防止产生偏倚的措施：
（1）正确的研究设计：随即化、标准化方法，研究变量的选择及测量 （2）提高研究对象的依从性 （3）培训研究人员 （4）严格校正仪器
（5）严格实验条件及研究方法。
2. 普查的目的：（1）早期发现病人；（2）了解疾病分布；（3）了解人群健康水平；（4）建立某生理指标的正常值。
普查适用于那些有一定患病率，危害严重且有简便易行的诊断手段，而早期发现后能有满意治疗效果的疾病；建立某生理指标正常值需要用普查。
普查的优点：（1）确定调查对象上比较简单；（2）可查出某人群中患某病的所有病人，使其得到及时治疗；（3）开展干预如健康教育，了解某病的患病率或健康状况。
普查的缺点：（1）普查对象多，调查期限短难免漏查；（2）调查质量不易控制；（3）患病率低、诊断技术复杂的疾病不易进行普查。 抽样调查的优点：省时间、省人力、省物力，调查结果准确。
抽样调查的缺点：设计、实施及资料分析比普查复杂；重复或遗漏不易被发现；对于变异过大的材料和需要普查普治的情况则不适合用抽样调查；患病率太低的疾病也不适合抽样调查。
实习 队列研究
(一) 名词解释
? Exposure, Risk factor，outcome
? Cohort, Birth cohort, Exposure cohort
? Fixed cohort, Dynamic cohort or open cohort
? Cohort study/Prospective study /Follow-up study /Longitudinal study /Incidence
study
? Prospective cohort study or concurrent cohort study, Historical (Retrospective or
non-concurrent ) Cohort Study, Ambispective (or mixed) cohort study ? Person time
? Risk, Cumulative incidence, Incidence density ? Standardized mortality ratio (SMR)
? Re1ative risk (RR), risk ratio (RR)，rate ratio (RR) ? Attributable risk (AR), rate difference (RD), excess risk ? Attributable risk percent (AR％) etiologic fraction (EF)
? Population attributable risk (PAR), population attributable risk percent (PARP) ? Lost to followup bias （二）单选题 （选择一个最佳答案）
1. In cohort studies of the role of a suspected factor in the etiology of a disease, it is
essential that: D
a. There be equal numbers of persons in both study groups
b. At the beginning of the study, those with the disease and those without the disease
have equal risks of having the factor
c. The study group with the factor and the study group without the factor be
representative of the general population
d. The exposed and nonexposed groups under study be as similar as possible with
regard to possible confounding factors e. Both b and c 2. Which of the following is NOT an advantage of a prospective cohort study? A a. It usually costs less than a case-control study b. Precise measurement of exposure is possible c. Incidence rates can be calculated
d. Recall bias is minimized compared with a case-control study e. Many disease outcomes can be studied simultaneously.
3. Retrospective cohort studies are characterized by all of the following except: C a. The study groups are exposed and nonexposed b. Incidence rates may be computed
c. The required sample size is smaller than that needed for a prospective cohort study d. The required sample size is similar to that needed for a prospective cohort study e. They are useful rare exposures
4. A major problem resulting from the lack of randomization in a cohort study is: A
a. The possibility that a factor led to the exposure, rather than the exposure itself,
might have cause the disease
b. The possibility that a greater proportion of people in the study may have been
exposed
c. The possibility that a smaller proportion of people in the study may have been
exposed
d. That, without randomization, the study may take longer to carry out e. Planned crossover is more likely. 5. In a cohort study, the advantage of starting by selecting a defined population for study
before any of it members become exposed, rather that starting by selecting exposed and nonexposed individuals, is that: C
a. The study can be completed more rapidly
b. A number of outcomes can be studied simultaneously c. A number of exposures can be studied simultaneously d. The study will cost less to carry out e. a and d 6. Classify each of the studies (6.1-6.7) described below as either a
a. Trial
b. Cohort study,
c. Case-control study
d. Cross-sectional study, or e. Ecological study
6.1 A study investigated the relation between prostate cancer and energy restriction during
childhood by examining prostate cancer occurrence in 58,279 men aged 55-69. The authors found no evidence that energy restriction early in life decreased prostate cancer risk later in life. B 6.2 A study compared tea consumption in heart disease patients and a series of non-cases to
determine if tea consumptions was protective. C 6.3 Surgical patients were assigned to one of three groups. Group 1 received antibiotics 24
hours prior to surgery, group 2 received antibiotics 2 hours prior to surgery, and group 3 received no antibiotics. Risks of post-operative were compared. A 6.4 Researchers in Liverpool, England published a landmark study in which 66% of the
mothers who had given birth to infants with spinal cord malformations were folic acid deficient. In contrast, only 17% of the mothers who had normal babies were folic acid deficient. C 6.5 The British Research Council completed a study in which some of the women in a group
who had given birth to babies with neural tube defects in the past and who were once again pregnant were supplemented with folic acid. The investigators found that supplementation reduced the risk of having second neural tube defect baby by 70%. A 6.6 At the Mayo Clinic in Rochester, Minnesota, researchers followed 939 patients who had
been classified as either optimists or pessimists. After thirty years of study a greater percentage of optimists were alive than pessimists. B 6.7 A population-based sample showed higher prevalence of diabetes in Hispanics whites
than non-Hispanic whites. D