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The CDC National Office of Public Health Genomics (NOPHG) in collaboration with several CDC programs and NIH institutes has embarked on a public health initiative to evaluate the use of family history information for assessing risk for common diseases and influencing early detection and prevention strategies. This document describes the major components of the public health initiative including formation of workgroups, development of family history tools, and development of a research agenda to assess the validity and utility of using family history for disease prevention.
It has been known for years that people that have close relatives with certain diseases like, heart disease, diabetes, and cancers, are more likely to develop those diseases themselves. However, it is clear from our public health work as well as our personal experience with the health care system that family history is underutilized in the practice of preventive medicine. Geneticists have long recognized the value of family history for discovering inherited disorders, usually the result of single gene mutations. Although single gene disorders are typically associated with a large magnitude of risk, they account for a small proportion of individuals with a genetic risk for common, chronic diseases. Most of the genetic susceptibility to these disorders is the result of multiple genes interacting with multiple environmental factors. Family history is more than genetics, it reflects the consequences of inherited genetic susceptibilities, shared environment, shared cultures and common behaviors. All of these factors are important when estimating disease risk.
In early 2002, NOPHG began the family history initiative with a review of the literature and a paper that proposed the use of family history for disease prevention and described an evaluation framework for determining the effectiveness of the approach (Yoon PW, et. al. Genet in Med 2002; 4(4):304-310). The framework was originally developed by the Foundation for Blood Research to evaluate predictive genetic tests but can be applied to family history screening. The four components of the framework are analytic validity (how accurately disease among relatives is reported), clinical validity (ability of family history to predict future disease), clinical utility (impact on healthy behaviors and health status), and the ethical, legal and social implications of collecting and using family history information.
In May 2002, NOPHG convened a panel of experts to review what is known about family history as a risk factor for selected diseases, and discuss how useful knowledge of family history might be for motivating people to change their behavior. Ten articles based on workshop presentations were published in the February 2003 issue of the American Journal of Preventative Medicine.
Information learned from the workshop was used to inform the development of a long-term research initiative. The initiative includes analysis of existing datasets to fill gaps in knowledge about validity and utility of the family history approach; development of a family history data collection tool and a resource manual for health care providers; creation of pilot studies and funding opportunities for evaluating the tools and eventually for evaluating public health campaigns and physician education programs. A national working group was formed to provide guidance and expertise for the many components of the research initiative. The multidisciplinary working group includes representatives from CDC, NIH, other federal agencies, state public health programs, academia, and the health care community. The workgroup conducted an extensive review of existing family history tools and developed criteria for a tool that focused on the prevention of common chronic diseases.
Criteria for diseases that should eventually be included in the tool –
1. Substantial public health burden
2. Well defined case definition
3. High awareness of disease status among relatives
4. Accurately reported by relatives
5. Family history is an established risk factor
6. Population prevalence of family history as a risk factor can be estimated
7. Effective interventions exist for primary and secondary prevention
8. Different recommendations for familial risk groups may be possible
After reviewing a list of approximately 45 diseases (compiled from other family history tools) and applying the inclusion criteria, the work group narrowed the list to 15 diseases. The work group met in-person in May 2003 and decided that the prototype family history tool should include only a few diseases to facilitate pilot testing and evaluation of the tool in different population-based settings. The prototype being developed includes - heart disease, stroke, diabetes, and breast, ovarian and colorectal cancer. Diseases will be added to the tool as they are validated.
The idea for using family history as a public health strategy is to develop a family history tool that is simple, easily applied and adaptable to different settings. The electronic tool that is being developed is web-based and will eventually include applications for stand-alone PCs and hand-held devices. Patients can use the tool in a provider’s office or at home before a medical consultation. The tool includes algorithms in the software that interpret the data and provide a brief synopsis of disease risk and suggestions for follow-up. Patients and their providers can discuss the implications of the family history information and keep it updated during annual visits. The goal is to keep it simple but gather enough information to classify people into risk groups. One underlying scheme being considered has 3 risk groups – average, moderate, and high – that are determined mainly by the number of relatives affected and their age at disease onset (Scheuner MT, et al. Am J Med Genet 1997; 71: 315-324.) The risk classification will be used to guide and inform prevention activities (Figure 1). People at average risk would be encouraged to adhere to standard public health recommendations for maintaining good health. People with an increased risk (high and moderate) could be given personalized prevention recommendations such as lifestyle changes or early detection strategies. People at high-risk could be referred for a consultation with a geneticist or other appropriate specialist. A resource manual is being developed for primary care providers that includes an explanation of the risk levels, recommended interventions for each level of risk, an explanation of potential Mendelian conditions underlying high risk (e.g., HNPCC for colorectal cancer), and additional resources for the patient and providers such as websites, brochures, and fact sheets.
A beta version of the tool that includes the data collection instrument, risk algorithms, and patient report is scheduled for completion by September 2005. Numerous groups and individuals (HMOs, the military, academia, and private practices) have expressed interest in testing the tool in varied settings. The workgroup will be developing letters of agreement and criteria for evaluation for the pilot studies. In addition, CDC has awarded funding to three research centers--the University of Michigan School of Medicine, Evanston Northwestern Healthcare Research Institute, and Case Western Reserve University School of Medicine—for a collaborative study set in primary care clinics. The study will use the tool to determine whether family history risk assessment, classification, and personalized prevention messages influence health behaviors and the use of preventive medical services. Additional studies will be developed to evaluate the validity and utility of the tool in other public health and preventive medicine settings.
As part of the research agenda, the work group has also identified completed and ongoing studies that have collected family history data. Analyses of family history data that has already been collected in population-based studies may help fill some of the gaps in our understanding of the attributable fraction of disease due to family history and the validity and utility of using family history information to prevent disease.
>> More Information on Family History
Figure 1. Proposed scheme for using family history to guide and inform prevention activities.
- Yoon PW, Scheuner MT, Khoury MJ.Research Priorities for Evaluating Family History in the Prevention of Common Chronic Diseases. Am J Prev Med 2003;24:
- Hunt SC, Gwinn M, Adams TD. Family History Assessment : Strategies for Prevention of Cardiovascular Disease. Am J Prev Med 2003;24:136-142.
- Sharon LR Kardia, Modell SM, Peyser PA. Family-Centered Approaches to Understanding and Preventing Coronary Heart Disease. Am J Prev Med 2003;24:
- Harrison TA, Hindorff LA, Kim H, Wines RCM, Bowen DJ, McGrath BB, Edwards KL. Family History of Diabetes as a Potential Public Health Tool. Am J Prev Med 2003;24:152-159.
- Burke W, Fesinmeyer M, Reed K, Hampson L, Carlsten C. Family History as a Predictor of Asthma Risk. Am J Prev Med 2003;24:160-169.
- Keku TO, Millikan RC, Martin C, Rahkra-Burris TK, Sandler RS. Family History of Colon Cancer : What Does it Mean and How is it Useful? Am J Prev Med 2003;24:170-176.
- Bowen DJ, Ludman E, Press N, Vu T, Burke W. Achieving Utility with Family History : Colorectal Cancer Risk. Am J Prev Med 2003;24:177-182.
- Audrain-McGovern J, Hughes C, Patterson F. Effecting Behavior Change : Awareness of Family History. Am J Prev Med 2003;24:183-189.
- Ziogas A, Anton-Culver H. Validation of Family History Data in Cancer Family Registries.
Am J Prev Med 2003;24:190-198.
- Tyagi A, Morris J. Using Decision Analytic Methods to Assess the Utility of Family History Tools. Am J Prev Med 2003;24:199-207.
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