Summary

In the mid-1980s, the Centers for Disease Control and Prevention (CDC) recognized the need to study genetic risk factors for common diseases such as diabetes and heart disease. To take advantage of a rare opportunity to obtain a nationally representative, population-based sample to study genetic risk factors, CDC collected and stored DNA as part of the Third National Health and Nutrition Examination Survey (NHANES III). At the time, the methods for studying these risk factors in large epidemiologic studies were not available. However, in the midst of planning for NHANES III, a revolution was occurring in the field of genetics. The resulting changes would provide a means to realize the goal of explaining why some people are more susceptible than others to risks such as elevated cholesterol or exposure to carcinogens. During this period, ethicists were increasingly asking questions about the safety and risks for participants in genetic research. Was genetic research different from other research? Were new rules for obtaining informed consent for genetic research needed, or should our methods of obtaining informed consent be equally rigorous for all research?

When collection of the NHANES III DNA Bank was complete in 1994, CDC and the National Institutes of Health (NIH) held a workshop to address these questions. The published recommendations of this workshop stimulated a national debate that resulted in a significant change in the way genetic epidemiologic research is done in the United States including not only stored biologic specimens but data collected for one purpose but used for another.

In 1999, the National Bioethics Advisory Commission (NBAC) published recommendations for the ethical use of human biological materials. The recommendations of NBAC and policies and practices of CDC about informed consent for research on stored tissue samples will serve as models for future epidemiologic research. The problems that were recognized in the national debate that ensued and the solutions that followed will affect the way we gain access to biological specimens and data in the 21^st century.

This is a story about the challenges that we face today. Today in public health and epidemiologic investigations we face complex challenges with regard to using specimens and data that were collected for one purpose but have value for another. In response to public health needs, the Centers for Disease Control and Prevention (CDC) often used banked specimens and data to answer questions that arose.

In one instance, when CDC sought to use stored specimens for which it had received permission from survey participants to use their specimens for research, questions arose that would challenge the use of stored specimens for new epidemiologic research. In the process of answering those questions, CDC re-evaluated its use of stored specimens. One of the greatest ethical challenges that CDC faced in deliberations about use of the stored specimens was how to balance the individual's right to refuse or agree to take part in research with the social benefits that can accrue if people do participate in research. At a time when technologic advances offer easy access to information, we must ask ourselves whether we can use stored specimens and data that were collected for another purpose. Can we do so ethically and in a way that will not harm people? The word "harm" has many shades of meaning. One ethicist posed this scenario to show how seemingly benign actions might do harm:¹ "Someone comes into your house. You are not there. You do not know who he is. He does not know you. He does not touch anything, but looks at everything in your house and leaves. You never knew he was there." Has he done you harm? Some ethicists would argue that the person violated your privacy or autonomy because you did not give him permission to enter your house. However, others would argue that this look at your house and your belongings, could provide information that will significantly help others, including your family? Would people be willing to cede some privacy or autonomy in the service of benefitting society?

In the mid-1980s CDC recognized that in the near future scientists would be able to study genetic risk factors for common diseases. CDC decided to take advantage of a unique opportunity to collect a population-based sample of DNA that was nationally representative and to store the DNA until the technology needed to perform studies on the specimens was available. While CDC was considering this action, three important events converged to make this collection of DNA feasible.

First, the initial publication describing the polymerase chain reaction (PCR) had recently appeared.² PCR is a way to amplify DNA from a small amount of a person's blood for use in genetic studies. Although not yet in widespread use, this technology held great promise for genetic research.

Second, a U.S. Senate committee was working on legislation that would create the Human Genome Project at the National Institutes of Health.³ The aim of this project was to map and sequence the entire human genome by 2005.

Third, CDC staff began to discuss with representatives of the scientific community methods of collecting and storing DNA as a part of the Third National Health and Nutrition Examination Survey (NHANES III).⁴ NHANES is a family of surveys that began in 1966. These surveys estimate the prevalence of common diseases and their associated risk factors, determine secular trends for the diseases and risk factors; and help explain the causes and natural history of some diseases.

NHANES is the only nationally representative survey that includes a physical examination and specimen collection. For example, in NHANES III bone density and blood pressure were measured and cardiograms were performed. Thousands of pieces of information representing the phenotypic expression of genes were collected on survey participants. The value of this survey is demonstrated in findings such as that which showed that blood-lead concentrations in the U.S. population decreased in parallel with the removal of lead from gasoline.

In planning to collect DNA, there was no consensus about the type of specimen that would be stored. Options included purifying and storing DNA or freezing and storing blood cells from which to extract DNA many years later. But these options provided only a finite source of DNA. In order to share the DNA with researchers, more would be needed. Blood cells, called lymphocytes, can be cultured and kept alive through a finite number of cell divisions, and then they die. However, a virtually unlimited source of DNA can be obtained if lymphocytes are immortalized, a process in which the lymphocytes are infected with Epstein-Barr virus in the laboratory so that they can be frozen and later thawed to further divide and create more cells.

In order to do this, however, the blood specimens had to arrive at the central laboratory within 12 hours of their collection so that they could undergo complicated processing. Meeting this deadline was often logistically impossible for this nationally representative survey. At the time that CDC was planning NHANES III, a blood drawing tube (Vacutainer-CPT^TM ; Bectin-Dickenson, NJ) became available that allowed for the collection of specimens in the field and the necessary separation of white cells from red cells. This extended the time from blood drawing to arrival at the laboratory from 12 to 72 hours, thus making it possible to immortalize cells.

Events then converged to help us meet the challenge of creating a DNA bank containing sufficient DNA to allow researchers to study genetic risk factors for disease. The Human Genome Project would map the genes that altered risk; PCR would provide technology needed to create sufficient quantities of DNA, and NHANES would give us a mechanism to obtain a nationally representative sample. Thus, we began to immortalize cells.

By 1994, approximately 18,000 specimens had been collected in NHANES III. Of those specimens 8,500 specimens were in the form of immortalized cell lines which provided a virtually unlimited source of DNA. With this cell bank, researchers could investigate the prevalence of genetic risk factors for common diseases such as diabetes and heart disease and study the relationship between genetic and environmental risk factors.

However, developments in genetics accelerated during the period from 1988 through 1994. Kerry Mullis had won the 1993 Nobel Prize in chemistry for his development of the polymerase chain reaction. The National Center for Human Genome Research (NCHGR) was created, and Congress mandated that NCGHR devote 5 percent of its $3 billion budget to address the ethical, legal, and social implications of the Human Genome Project. As a result, NCHGR created the Ethical, Legal and Social Implications Branch.

During those 6 years a body of literature was created that addressed the ethical issues related to genetic testing and research. Much of the work done on these issues was made possible by NCHGR funding.⁵ CDC was also preparing to accept proposals from researchers around the country to use the DNA Bank and the vast amount of data linked to those specimens.

In the process of creating a mechanism for scientists to obtain the DNA, CDC reviewed the informed consent documents used in NHANES III. The purpose of the consent is to ensure that people understand what they are agreeing to, that they know the associated risks and benefits, and to document that they freely consent to participate. The NHANES III consent was in a question-and-answer format. For example, one question is, "Will the test that you are asking me to take harm me?" The answer was, "We care about your safety. The test and measurements that we do have been chosen because they are safe." The risks that were described in the informed consent form were those associated with blood drawing (e.g., bruising and soreness).

The consent form also told participants that some of their blood would be saved for later research. The form named some tests that would be used. As was standard in 1988, the information on what their specimens would be used for was general rather than detailed so that participants would understand what they read. Initially, DNA was mentioned in a draft of the consent form but later removed. The Institutional Review Board (IRB) believed that mention of DNA would be more confusing than enlightening for participants, and at that time, no specific DNA testing was planned.

By 1994, in light of the body of literature that had developed about informed consent and because the NHANES III consent form did not mention DNA, CDC was uncomfortable with using linked samples to do genetic research. As a result, CDC and NCHGR jointly sponsored a workshop to revisit issues of informed consent. Ethicists, lawyers, and researchers were invited to participate in these discussions.

Ellen Wright Clayton, Professor of Pediatrics and Law at Vanderbilt University and chairperson of the workshop, presented draft recommendations to the workshop for discussion. Particpants were predictably polarized on the competing issues relating to a person's right to refuse or agree to take part in research and the social benefits that can accrue when people did participate. Francis Collins, the Director of the NCHGR (today, the National Human Genome Research Institute), named a writing group to develop recommendations. As a result, recommendations were published that represented a compromise between the two ends of the spectrum. These recommendations were published in the Journal of the American Medical Association in 1995.³

The recommendations stated that 1) informed consent is required for all genetic research using linkable samples unless conditions of federal regulations for limitation or waiver of this requirement are met; 2) informed consent is not required for genetic research using anonymous samples but may be considered appropriate if identifiers are to be removed from currently identifiable samples; and 3) Institutional Review Boards (IRBs) could usefully review all protocols that propose to use samples for genetic research.

During the four years since the recommendations were published, a national debate has continued about the recommendations and informed consent for stored specimens. Researchers at CDC and elsewhere struggled to balance the opposing principles of autonomy with the benefits to the individual and society, but a more definitive response was in the making.

In 1995, President Clinton established the National Bioethics Advisory Commission (NBAC) in response to controversy about human radiation experiments. NBAC was convened originally to address two topics within 2 years. One topic was the use of human biological materials and research, and the other was implementation of the regulations. The NBAC has recently published recommendations for the ethical use of human biological materials.⁷

For a time genetic research seemed in jeopardy, perhaps because researchers and ethicists were trying to obviate every possible nightmare scenario that could arise. But NBAC has helped to ameliorate this issue by saying, "Not all of the interests that weigh in favor of more stringent restrictions on access are of equal weight, and some are of questionable importance especially given their low probability of occurring." Now, genetic research on stored samples may be treated more like other research. Conversely, other research may be treated more like genetic research, which implies the adoption of a higher level of scrutiny.

Scientists at CDC have spent much of the last 5 years wrestling with issues related to the ethical use of stored specimens and data to increase the body of scientific knowledge and improve public health. We learned a great deal in the process.

NHANES IV has begun, and DNA is being stored. The consent form now includes an explanation of the use of DNA. However, in part because of the deliberations of NBAC, the explanation is not as stringent as that proposed in the 1994 workshop which would have required the researchers to predict for participants every single gene that might be studied in the future. Now, a more generic statement tells participants that, if they agree, their specimens will be kept for an unlimited time for future genetic research, but if, in the future, the participant wants their specimen removed from the collection, they can call a toll-free number given in the consent.

We have made considerable progress in the last 10 years while trying to ensure that information on genetic risk will benefit public health and at the same time protect those who provide specimens by which we obtain that information. Although we have come to realize that an understanding of the genetic component of risk for common diseases will require more innovations in genetic technology and methods for making sense of vast amounts of information simultaneously,⁸ population-based samples such as NHANES with their linked phenotypic data will still be vital to that understanding.

References

1. Capron A.M., ‘Protection of research subjects: Do special rules apply in epidemiology?' Journal of Clinical Epidemiology 44, Suppl 1: 81S-89S (1991).
2. Saiki, R.K., Bugawan, T.L., Horn, G.T., Mullis, K.B., and Erlich, H.A. Analysis of enzymatically amplified $-globin and HLA-DQ " DNA with allele-specific oligonucleotide probes. Nature, 324, 163-166 (1986).
3. Watson, J.D. The human genome project: past, present and future, Science, 248, 44-49 (1990).
4. National Center for Health Statistics. Plan and operation of the Third National Health and Nutrition Examination Survey, 1988-94. Vital Health Statistics, 1(32), (1994).
5. Andrews, L.B., Fullarton, J.E., Holtzman, N.A., Motulsky, A., Eds. Assessing genetic risk: Implications for health and social policy. Washington, D.C.: National Academy Press.
6. Clayton, E.W., Steinberg, K.K., Khoury, M.J., Thomson, E., Andrews, L., Kahn, M.J., and Kopelman, L.M. ‘Informed consent for genetic research on stored tissue samples. JAMA 1995;', Journal of the American Medical Association, 247:1786-92 (1995).
7. National Bioethics Advisory Commission. Research involving human biological materials: Ethical issues and policy guidance. August 1999;, Rockville, MD, August 1999, (
8. Collins F.S., Patrinos, A., Jordan, E., Chakravarti, A., Gesteland, R., and Walters, L. New goals for the U.S. Human Genome Project: 1998-2003. Science, 282, 682-689 (1998;282:682-9).