10 Oct Do you agree or disagree with using humans as part of research studies? Why or why not? -Summarize potential benefits and challenges with studying humans during research including e

Chapter Objectives

After reading this chapter, students will be able to:

1. Define interventional studies

2. Define cohort studies

3. Define case control studies

4. Describing issues with using human subjects in research studies

5. Describe sources of errors when conducting research studies

6. Describe the ethical issues with using human subjects in research studies

7. Provide examples of different clinical trials/research studies

8. Describe conflicts of interest in drug trials.

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CHAPTER 6

PROBLEMS AND LIMITS OF EPIDEMIOLOGY

CHAPTER 6

PROBLEMS AND LIMITS OF EPIDEMIOLOGY

Chapter 6 Notes

MAJOR THEMES

1. Because epidemiology studies humans, there are many limits to how research can be conducted and many pitfalls in interpreting the results. Limits are imposed by ethical considerations and because researchers cannot control the behavior of their subjects.

2. Each type of epidemiologic study is subject to certain types of errors. Sources of error include random variation, especially likely in small studies, and various forms of bias and confounding.

3. Even well-designed studies may produce erroneous findings. Clinical trials are considered to yield the most accurate results, and cohort studies the next most accurate. When conflicting results are found by different major studies, epidemiologists are challenged to understand what has led to these differences. This has been the case with two major trials on the health effects of hormone replacement therapy for post-menopausal women.

4. Current studies on humans funded by the federal government must obey strict ethical rules including informed consent by the patients and review of the study design by institutional review boards.

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IMPORTANT TERMS

confounding variables selection bias reporting bias

recall bias Tuskegee study informed consent

institutional review board

FURTHER READINGS AND WEB SITES

1. Web site of the Hastings Center, which conducts research on ethical issues in health, medicine, and the environment: www.thehastingscenter.org/

CHAPTER 6

PROBLEMS AND LIMITS OF EPIDEMIOLOGY

CHAPTER 6

PROBLEMS AND LIMITS OF EPIDEMIOLOGY

REVIEW QUESTIONS

1. In a case-control study that found an association between breast cancer and air pollution, 500 women who had recently been diagnosed were asked what industries were within a mile of their home twenty years ago. The controls were 500 healthy women. What is the most likely source of error in this study?

a. Random variation

b. Reporting bias

c. Selection bias

d. The placebo effect

2. In a cohort study that found an association between alcohol consumption and bladder cancer, 20,000 middle-aged men were asked about their drinking habits and then tracked for five years to watch for the development of cancer. Researchers asked the men about their diet and exercise habits, but not about smoking. What is the most likely source of error in this study?

a. The placebo effect

b. Reporting bias

c. Selection bias

d. Confounding variables

3. In an intervention study to determine whether a vegetarian diet can help college women to lose

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weight, 500 residents of a women's dormitory were divided into two groups: one that ate in a vegetarian dining hall and one that ate a normal diet. Women were allowed to choose which group they wished to be in. After three months, the vegetarian group had lost an average of 10 pounds while the control group had not lost weight. What is the most likely source of error in this study?

a. The placebo effect

b. Reporting bias

c. Selection bias

d. Random variation

4. An announcement was made in a college dormitory that, for the next month, a natural foods company was testing an herbal tea for its effectiveness in curing headaches. Any time that a resident had a headache, he or she was given a free sample of the tea and asked to complete a questionnaire the following day on whether the tea had helped. What is the most likely source of error in this study?

a. The placebo effect

b. Reporting bias

c. Confounding variable

d. Random variation

CHAPTER 6

PROBLEMS AND LIMITS OF EPIDEMIOLOGY

5. Which of the following statements about ethics and epidemiology is true?

a. The Tuskegee syphilis study was not unethical because the men were probably not harmed by withholding antibiotic treatment.

b. The aspirin portion of the Physicans’ Health Study was halted early for ethical reasons

c. Because AIDS is a fatal disease, it is unethical to conduct clinical trials on AIDS treatments.

d. It is unethical for insurance companies to deny bone marrow transplants, an expensive experimental procedure, to women with advanced breast cancer.

(Answers: b, d, c, a, b)

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