Not long ago, I toured the new UCSF Bakar Precision Cancer Medicine Building, which brings together clinicians, researchers and supportive care in one building. It is a truly spectacular facility that brings the promise of precision medicine to UCSF patients. That got me thinking about just how unique each of us is and what that means for health care delivery.
I recently took a look at my DNA and ancestry results, and I have to admit the results were intriguing to say the least. In fact, the revelations prompted an interesting family discussion about asparagus pee. Did you know that some people have a gene that allows them to smell a distinct asparagus-generated odor after ingesting a few spears? To put it precisely, the digestion of asparagus produces methanethiol and S-methyl thioesters, which are chemical compounds containing stinky sulfur. While others are genetically spared, I’m apparently blessed with the right genomic makeup to appreciate its distinct smell. My wife sure thought that was amusing. (She also finds it remarkable that I have a low level of the Neanderthal genome given some of my “caveman” tendencies.)
All kidding aside, I am excited by the continual advances in science that are allowing us to learn more about the relationship between genes, behavior, and the environment. This is the basic premise of precision medicine – to understand why some people get sick under certain conditions while others do not, and to guide more precise and predictive treatments. For more than a century, human geneticists have studied variations in single genes and their effect on disease risk. The study of genes, genetic variations, and heredity has opened up vast opportunities for translation of basic science research to health care. Precision medicine takes that pioneering work further by integrating other scientific and research data to provide clinicians with a more holistic view of a person’s unique situation.
A prime example is dental caries (tooth decay). We once thought that sugar intake and bacteria plaque were the only risk factors for caries, the most common oral health disease. We now know that host resistance and other genetically determined risk factors can contribute to caries. In fact, some studies have estimated that 40 to 60 percent of caries susceptibility is genetically determined. While people don’t actually have soft teeth, the increased predisposition to tooth decay in some people correlates with the absence of a protein that is crucial for normal enamel development; gene coding for that protein influences dental caries.
There’s no doubt genetics play an important role in the diagnosis and management of disease, but the last 10 years in particular have seen rapid improvement in the field of genomic medicine. While the promise of genomic technologies to improve health may have been hyped and oversold in the past, we now are seeing the leading edge for applications of whole genome sequencing in health practice. Detection and control of infectious disease outbreaks, and the diagnosis of people with rare diseases, are two areas that have advanced thanks to genomic medicine.
With science advancing at such a rapid pace, it’s remarkable that, in the United States, the key to your health might actually lie in a different type of code… your ZIP code.
In a report on morbidity and mortality, the Centers for Disease Control and Prevention looked at the annual number of potentially preventable deaths from five leading causes. These included heart disease, cancer, chronic lower respiratory disease, cerebrovascular disease (stroke), and unintentional injuries. Comparing death rates by state and cause, the CDC found that states in the Southeast had the highest number of potentially preventable deaths.* Unfortunately, the publicity surrounding these findings tends to sensationalize and over-interpret the results with statements like, “Living in a rural environment is bad for your health,” or “Lifespan has more to do with geography than genetics.” The reality is that most human diseases affecting quality of life, including those that manifest in the oral cavity, result from the interaction of our genetic susceptibility with environmental and behavioral risk factors like diet, physical activity, infectious agents and the physical environment. Ultimately, death rates are population health outcome measures that reflect the combined influences of biological and social health determinants, public health efforts and medical care. The thought that something as simple as saliva bioanalysis can make a difference could revolutionize the concept of going to the dentist.
Since both genetic codes and ZIP codes are important pieces of the same big puzzle of health, academic health centers have the opportunity to play a leading role in understanding both biological and environmental influences. It’s for the good of our population and for ourselves. Likewise, we as individuals can control at least a few of our own health factors through our behaviors and choices. So taking my own personal cue, for the Fourth of July weekend I plan to up my exercise and eat something healthy — and yes, I will cook it with fire, the way a caveman would.