Explore This Issue
December 2013
The phrase “health and wellness” seems to be everywhere. Essentially, it’s based on the belief that healthy behaviors—such as proper diet and exercise, avoiding alcohol and tobacco use and good stress management—and early detection of disease are the best way to stay well. And yet, our medical system is set up to be reactive: We wait for illness to occur, and then we run to our doctors.
Michael M.E. Johns, MD, an otolaryngologist who recently stepped down as chancellor of Emory University in Atlanta and co-authored the book Predictive Health: How We Can Reinvent Medicine to Extend Our Best Years (Basic Books, 2012), has been working toward reversing that dynamic. At the Emory-Georgia Tech Predictive Health Institute, researchers are following healthy volunteers and tracking a variety of biomarkers they believe will monitor different aspects of health. At the clinic, volunteer subjects also meet with health coaches to improve their lifestyle habits.
If you look at the human body as a collection of metabolic processes, said Dr. Johns, “We see regeneration of cells in tissues such as the skin and the gut. There are inflammatory processes and immune processes. When these systems go haywire, we get disease.”
For instance, arthritis is defined as inflamed joints, but coronary artery disease and diabetes can also be considered problems of inflammation. So, by focusing on these metabolic processes, rather than single organs or somatic symptoms, physicians might have a more holistic way to detect and diagnose disease, perhaps even before it occurs.
“It’s a great concept, to prevent disease. It’s the holy grail,” said Bert O’Malley, Jr., MD, Gabriel Tucker Professor of otorhinolaryngology at the University of Pennsylvania in Philadelphia. “It’s also extremely challenging, especially in terms of understanding how to intervene.”
As predictive health researchers collect data and identify telling biomarkers, however, doctors must still address health and disease in their practices. What does predictive health mean for the practice of otolaryngology today? Sometimes it means early screening for common otolaryngology issues, and sometimes it means identifying characteristics of early disease to personalize treatment.
Hearing Loss
One of the most obvious ways to screen for otolaryngological health is testing the hearing of newborn babies. The tests themselves are not new, but their impact is profound, said Howard Francis, MD, associate professor and director of the Listening Center, the cochlear implant program at the Johns Hopkins Hospital in Baltimore. “These babies are at risk for poor language development because of their hearing impairment,” he said.
And yet, newborns cannot tell doctors or parents what they hear. Physiological events in the inner ear and the electrical activity of the brain can.
Hearing tests in newborns record otoacoustic emissions of the hair cells in the inner ear and the auditory brainstem response of babies exposed to sound. Patients who test poorly should receive a more detailed evaluation by an audiologist to determine which frequencies are affected and the severity of the loss. Sometimes close monitoring is all that’s needed, but in worst case scenarios, children can be given amplification devices “so they can begin the journey of language learning,” said Dr. Francis.
Genetic diagnosis of hearing loss later in life is a related field that is coming into its own, and there may be more than 200 different genes involved in deafness.
With the rapid progress in genetic sequencing methods allowing for increases in speed and capacity while decreasing costs, genetic testing is becoming routine in hearing loss evaluation. Comprehensive screenings are currently able to solve about half of the cases of nonsyndromic deafness, said Eliot Shearer, an MD/PhD student and researcher at the University of Iowa’s Molecular Otolaryngology and Renal Research Laboratories in Iowa City. Shearer helped to develop a clinical diagnostic tool called the OtoSCOPE, which has been available for clinical use for more than a year. This test can screen genes known to cause deafness.
Genetic testing is helpful in terms of counseling patients about prognosis and saves patients from unnecessary tests to rule out syndromic causes of deafness.
Still, to a certain degree, the genetics of deafness is a new enough field that, while testing can help characterize the biology of hearing loss, there’s not much impact on treatment decisions at this time, said Dr. Francis. Amplification, electrical stimulation and rehabilitation remain the go-to approaches.
Cancers Caused by HPV
Another area where preventive medicine is likely to play a larger role in otolaryngology practice is human papilloma virus (HPV) testing. In addition to its better known outcome of cervical cancer in women, HPV can cause oropharyngeal cancer in both women and men.
“Oropharygeal cancers are the fastest growing cancers in the United States,” said Dr. O’Malley. Almost everyone has been or will be exposed to HPV, which is transmitted through sexual contact, at some point during their lives. Some of those exposures will result in active infections, and some of those will cause cytological abnormalities that can convert to cancerous growth.
There is a test for early cellular changes in the throat, analogous to a Pap smear, but its utility is still being evaluated (Cancer Prev Res (Phila). 2011;4:1346-1349). There’s also hope that widespread adoption of the HPV vaccine will prevent many cases of oropharyngeal cancer.
Meanwhile, genetic analysis of head and neck cancers continues, a very active research area, with the hope of personalizing treatment based on a tumor’s molecular signature. (Adv Exp Med Biol. 2013;779:165-177; Head Neck Oncol. 2010;2:8).
Chronic Sinusitis
New work also suggests that typing bitter taste receptors in patients with recurrent sinus or upper respiratory tract infections may inform treatment strategies (J Clin Invest. 2012;122:4145-4159). “Bitter taste receptors exist in the respiratory mucosa,” said Dr. O’Malley, “and specific recep-tors are involved in the detection of specific types of bacteria.” Genetic variability of those bitter taste receptors affects the strength of the response and explains a great deal of individual variability.
With some 20 million visits for chronic sinusitis every year in the U.S. and a half million surgeries to fix the problem, said Dr. O’Malley, “it’s a significant health care issue.” A test that can identify the bitter taste receptor genotype might help determine who would benefit from surgery versus a course of antibiotics.