Family Health History Still an Important Tool for Clinical and Public Health Practice, but Knowledge Gaps Remain
CDC addresses public health implications of the findings and recommendations just released by a multidisciplinary panel of the Family History State-of-the-Science Conference hosted by the National Institutes of Health in Bethesda, Maryland, on August 24-25, 2009. Access the panel’s statement.
Although the scope of this conference was limited to primary care, and the panel’s findings and recommendations targeted the research community, the conference’s impact will likely be felt beyond these boundaries. As a partner in this conference and given our long-held support for the use of family history in public health, CDC’s Office of Public Health Genomics addresses the following potential implications of this conference for public health efforts conducted by CDC and its partners.
Family History and Clinical Utility for Single Gene Disorders
Advances in family history and genetics research have helped to establish the role of family history in the diagnosis and management of single-gene (Mendelian) disorders. Although these disorders are individually rare, collectively they present a significant public health issue, particularly among children. The Family History State-of-the-Science Conference did not include single gene disorders; however, in this area of medicine, the utility of family history in clinical settings and for individuals and their families has been demonstrated for many disorders. Still, we do not know the extent to which family history applications have been translated into clinical practice. This gap highlights a potentially important public health need for providing valid and useful genetic services to various communities, particularly those that are underserved.
Family History and Risk Assessment for Common Chronic Diseases
Most common human diseases are caused by complex interactions between a person’s genes, behaviors, and environmental exposures. Although there have been major scientific advances in understanding the behavioral causes (e.g., diet, smoking, and physical activity) of several chronic diseases, advances on the genetic causes of these diseases have been slower. Family history includes the genes, behaviors, and environmental exposures that relatives share in common. Research on the use of family history to assess disease risk has been inadequate, as has research on family history use in public health interventions for common diseases. Thus, family history, so far, has limited documented clinical utility in assessing the risk and targeting interventions for these diseases. However, family history, alone or in combination with other risk factors, increases the risk for common diseases, such as heart disease, stroke, diabetes, and various cancers, much more than genetic variants, alone or in combination, can predict. The familial risk often shows a dose-response effect. That is, the more close relatives a person has with a particular disease and the earlier their ages of diagnosis, the greater that person’s risk of also developing the same disease. Research on translating family history applications for risk assessment and disease prevention into clinical and public health practice is just beginning.
The panel pointed out numerous research efforts that are needed. The panel and others proposed the ACCE framework for evaluating the analytical validity, the clinical validity, the clinical utility, and the ethical, legal, and social aspects of using family history to prevent disease and improve the health of populations. Some research in this area is already under way. For example, CDC is collaborating with three universities to conduct a randomized controlled clinical trial to evaluate the clinical utility of Family Healthware™ as a risk assessment tool for six common diseases (breast, ovarian, and colorectal cancer, diabetes, stroke, and heart disease). The methods and some results of this clinical trial have been published, but more is on the way.1-3
Family History Risk Assessment Tool
Family history has been and will continue to be a core component of clinical and public health practice. Although the panel pointed out the lack of evidence on the effectiveness of the many applications and uses of family history, they did not recommend against the collection and use of this information for common diseases. Existing tools, such as the My Family Health Portrait from the U.S. Surgeon General, is helping to facilitate the collection and use of family history by individuals and in clinical and public health settings. This information can still inform clinical encounters with patients and public health surveillance efforts in programs involving common chronic diseases in populations. However, users need to be aware that there are significant gaps in applying our knowledge of family history to common diseases. The specific recommendations that emerged from this conference are a good first step in paving the way for addressing these gaps.
1Yoon PW, Scheuner MT, Jorgensen C, Khoury MJ. Developing Family Healthware, a family history screening tool to prevent common chronic diseases.
Prev Chronic Dis. 2009 Jan;6(1):A33. Epub 2008 Dec 15.
2Wang C, O'Neill SM, Rothrock N, Gramling R, et al. Comparison of risk perceptions and beliefs across common chronic diseases. Prev med. 2009 Feb;48(2):197-202.
3O'Neill SM, Rubinstein WS, Wang C, Yoon PW, et al. Familial risk for common diseases in primary care: the Family Healthware Impact Trial.
Am J Prev Med. 2009 Jun;36(6):506-14.