Kenneth Brigham, MD
Kenneth Brigham, MD, associate vice president and director of the Predictive Health Institute, Emory University.
Life was simpler back in the day when you called the doctor and he (for it was virtually always a he) said to take an aspirin and call back in the morning. Then again, back then, the on/off button was all you needed to operate your TV. Modern life is more complicated and wondrous — including the world of medicine, where miraculous treatments and new therapies keep people alive who’d previously never have survived. We get near-daily reports of breakthrough research linking particular genes to diseases, behaviors and other assorted health issues that it seems we may someday be able to bypass altogether.
How will this gene-based model of medicine impact life and health care in the coming years? To fill in the gaps I had a long conversation with an expert on predictive/personalized health, Kenneth Brigham, MD, associate vice president and director of the Predictive Health Institute, Emory University. First of all, he told me, it’s important to understand that predictive medicine (or health) is an umbrella term that covers several related concepts, including genetic medicine.
Genetic medicine, sometimes called simply genetics, has been with us a long time — more than 100 years in fact — and is now an integral part of research, patient information and even treatments. It relates to the presence and effects of a single gene in terms of predispositions, disorders and treatment. For example, one recent discovery of a gene variant can help doctors predict which patients are more likely to have complications after heart surgery… another is that some people have gene variations that render certain cancer drugs ineffective. Increasingly, genetic testing is done after diagnosis but before treatment, to help determine which approach to take.
Whereas genetic medicine looks at one-to-one connections between genes and disease, genomic medicine — or personalized or predictive health, as it is also called — is the larger entity. This much newer field considers the entirety of a person’s unique genomic structure (parts of your genetic structure that turn “on” and “off” and are influenced by age, environment, diet, etc.). The goal is to use your genomic expression to predict your individual susceptibility to diseases and other health issues before you get sick. Based on your genomic chart, your doctor can see where your risks are and instruct you how to change your exercise routine, diet, stress levels and the like to reduce your personal risks.
However, there are several key problems yet to be solved before genomic medicine/health can be practiced on a meaningful level, says Dr. Brigham. First, while some diseases involve single genes — for instance, muscular dystrophy, cystic fibrosis and sickle cell anemia — more commonly, diseases involve a number of genes and the interplay among them, as well as the many other variables that constitute life — foods you eat, stress, physical activity and so on. Examples include heart disease, type 2 diabetes, cancer and many others. The complexity of identifying genetic risk factors expands exponentially with such “multifactorial diseases.”
Neither is genomic information very useful in predicting individual risk. According to Dr. Brigham, at present risks are couched in terms of probabilities in a certain population, not for individuals. While you may have double the average risk for a particular disease, if the overall risk is one in a million it means your individual risk is in the area of two in a million, he explains — that’s so small, there’s not much, if anything, to do with the information. (Note: Beware of the personal genetic tests that are being sold direct to consumers today, as this is the kind of information they provide.)
Emory University has a predictive health program that is probably as close as most consumers can get to using personalized medicine today. Medical tests (blood chemistries, ultrasound, body scans) are used to evaluate markers of “un-health,” as Dr. Brigham calls them, which can be used to glean information about your personal health risks. At present, health insurance does not pay for these tests. The four markers measured are:
Dr. Brigham says that it is important to understand that this science is “still in its infancy.” However, he told me he feels confident that as we advance further in genomic understanding, medicine will shift from its current emphasis on disease-care to a system of true health care.