Genomics and Public Health: Potential Benefits Depend on Linking Genetic and Environmental Data in Designing Research, Developing Applications, and Forging Public Policies

Article excerpt

Breakthroughs in biology are changing our world. Just as chemistry and physics had broad ramifications in the preceding centuries, the New Biology unleashed by the Human Genome Project and associated developments will send ripples through many aspects of 21st-century life and will be influential in improving the health of the public. The public health sciences will be essential for interpreting the health significance of genetic variation and the gene/environment interactions at the core of most diseases and biological phenomena. The combination of genomics and public health sciences will be critical to achieve the vision of predictive, personalized, preventive health care and community health services (Table 1).

Public and media interest was intense when President Bill Clinton and Prime Minister Tony Blair jointly announced accelerated progress by the public- and private-sector sequencing programs in June 2000. The details of those "blueprints" for the 25,000 to 30,000 genes of the human genome sequence were published in February 2001. These genes, through a variety of pathways, produce an even larger number of proteins, which then undergo numerous structural modifications critical to their functions; thus, the "proteome" is much more numerous and complex than the genome.

Raw genome information reveals very little directly about human health. Genome sequence information must be linked with information about nutrition and metabolism; behaviors; diseases and medications; and microbial, chemical, and physical exposures from the environment in order to understand the environmental/genetic interactions that ultimately affect human health (Table 2). Broadly, genetics and public health share salient attributes. Both focus on populations. Both seek to elucidate the larger patterns to be found among individual variations in genetic predispositions to diseases, sensitivity to environmental exposures, and responsiveness to preventive and therapeutic interventions--within and across population subgroups. Both are aware of the legacy and risks of discrimination on social and racial grounds. Thus, both explicitly recognize the importance of cultural, societal, and ethnic contexts, often explored as part of the Human Genome Project's trailblazing investments in its Ethical, Legal, and Social Implications (ELSI) component.

Viewing health care as a part of public health, we can see that genetics provides a bridge between medicine and community-based public health, most directly in the setting of clinical genetics. Counseling and treatment of individual patients often must be expanded to nuclear or extended families. Screening for genetic predispositions involves workers and other populations suspected of having higher-than-background risks because of their exposure to potential hazards, their family history, or their ethnic background. Community outreach should be aimed not only at earlier diagnosis and treatment but at preventing problems by reducing nongenetic risk factors. The accelerating pace of discoveries and applications has put a premium on education about genetics for health professionals and education about public health for geneticists. Both disciplines have critical roles to play.

Epidemiology and randomized trials

During the past 15 years, there has been a remarkable transformation of epidemiology, highlighted by a dramatic move beyond simple statistical associations to cause-and-effect research that aims to identify the mechanisms of disease. Gene expression and protein expression are likely to be very useful early indicators of a developing disease. If this research is successful, then it will be possible to use gene or protein expression as a biomarker that will allow clinicians to identify preliminary signs of diseases with long latency periods before clinical symptoms and signs become manifest. Once etiological hypotheses have been generated and tied to credible potential mechanisms, investigators can devise clinical trials of prevention strategies that modify or remove relevant risk factors. …