A new federal grant of $16 million will guide the next five years of an ongoing, unprecedented study of the root causes of chronic head and neck pain conditions. The study of more than 6,000 adults by research and development organizations in four states is aimed at finding new diagnostic tests and better treatments for chronic pain sufferers, say study leaders.
Joel Greenspan, PhD, a professor in the University of Maryland (UM) School of Dentistry, says the Orofacial Pain Prospective Evaluation and Risk Assessment (OPPERA) study, now in its fourth year, is deepening scientists' understanding of risk factors and genetic markers for conditions, such as temporomandibular disorders (TMD), headaches, irritable bowel syndrome, low back pain, and chronic widespread pain.
The National Institute of Dental and Craniofacial Research (NIDCR) announced the funding for OPPERA II, which will support continued pain disorder research at the UM School of Dentistry's Department of Neural and Pain Sciences, the University of North Carolina (UNC) School of Dentistry's Regional Center for Neurosensory Disorders, the University of Florida at Gainesville, and the University at Buffalo The Battelle Memorial Institute's Center for Analytics and Public Health-a nonprofit organization headquartered in Columbus, Ohio-serves as the study's coordinating center. UNC's William Maixner, PhD, DDS, and Gary Slade, PhD, DDPH, are the program directors.
According to NIDCR, OPPERA II is designed to build on the findings in its preceding study, OPPERA I, which the agency funded with $17 million in 2008 for the pain research collaboration to identify the causes and point to possible cures for TMD.
Research in the first round of OPPERA, published in the Journal of Pain, showed that people with disorders of long-term jaw pain were much more sensitive to mildly painful sensations elsewhere in the body, more aware of body sensations, and experienced greater heart rate increases under mild stress. The findings provided new insights into potential causes of temporomandibular joint disorders (TMJD). In response to those findings, Greenspan says, "There is a real difference. People with TMJ[D]are more sensitive than those without TMJ[D] on parts of the body other than the jaw. To us it means the nervous system for interpreting pain information is now altered. We think that general heightened pain sensitivity is part of the chronic pain problem."
"Chronic pain is a substantial health problem-one that we're just starting to truly understand-that plagues more than 100 million U.S. citizens," says Maixner. "OPPERA II is critical to furthering our knowledge about human pain conditions. Once we better understand the causes of chronic pain and how one type of pain condition relates to another, we'll be better able to treat those who suffer daily from these disorders."
"Many chronic pain conditions, including chronic orofacial pain, are varied and complex in their etiologies and mechanisms," says Greenspan, principal investigator at UM. "It takes a large team of investigators, as we have assembled for the OPPERA studies, to attempt to understand the basis for chronic pain conditions, which include physiological, psychological, behavioral, and genetic factors." While all the university sites are conducting coordinated evaluations of study recruits, each site has made specific contributions to the project. UM has been particularly responsible for the development of protocols for pain sensitivity testing, which have been part of work carried out in UM's Brotman Orofacial Pain Center and Organized Research Center for Persistent Pain for more than 15 years.
The OPPERA II program will enroll 3,000 new participants and conduct follow-up assessments of them and of 3,200 adults previously studied in the OPPERA I program. The investigators will assess behaviors, psychological characteristics, genetic factors, and other biological mechanisms that contribute to the onset and persistence of common chronic pain conditions like TMD, headaches, low back pain, abdominal pain, and widespread pain. Researchers will look for commonalities as well as unique risk factors and biological mechanisms among the pain types.
"One thing we hope to accomplish is the identification of risk factors and biological mechanisms that cause the pain conditions to transition from an initial acute state to a persistent chronic state," says Maixner. "Most clinical pain conditions disappear with time, but certain individuals are susceptible to developing chronic pain states. We hope to identify environmental events and biological processes that mediate the transition from acute to chronic pain. We also intend to identify the underlying biological processes that permit the co-expression of common chronic pain conditions that overlap with TMD. By identifying these risk factors and biological pathways we will be able to provide diagnoses based on the mechanisms mediating the pain, which will hopefully provide better treatment approaches for millions of chronic pain sufferers."
Other organizations assisting with the research are the University of Washington, led by Bruce Weir, PhD, and Harvard University, led by Shamil Sunyaev, PhD.