Nov. 14, 2006 The observation that people with rheumatoid arthritis (RA) die at a younger age than people without this disease is not new, but arthritis experts don't fully understand the causes of the increased mortality rates. Laboratory scientists have observed that RA and other diseases can cause multiple systems within the body to age more rapidly than expected. Cells affected by diseases begin to show signs of what's called accelerated aging -- damage at the molecular level resulting in poorer function. Mayo researchers attending the American College of Rheumatology Annual Meeting will share preliminary findings that suggest increased mortality among people with RA is consistent with the concept of accelerated aging.
The Mayo research team conducted a population-based study that included 393 people diagnosed with RA. Examining medical records for the RA patients, Mayo researchers recorded the subjects' age at death and underlying cause of death. They compared the data from RA patients to expected survival data for people with similar birth dates and genders from the general population (obtained from the National Center for Health Statistics).
Mayo researchers then applied a novel mathematical tool to analyze the mortality data -- an accelerated failure time model. Doing this allowed researchers to estimate an "acceleration factor" that quantifies the rate of aging occurring among the study subjects with RA.
Significant findings: As expected, the observed survival rate for people with RA was consistently less than the expected survival rates for people in the general population. Researchers estimated that the RA patients in the study group aged at approximately 1.25 times the rate of people in the general population. Another way to express this finding is that during each 10-year time span, people with RA, in effect, age 12.5. "We've known for decades that the mortality rate among people with rheumatoid arthritis is higher, and that these patients are at increased risk for heart and lung disease," explains lead researcher and Mayo epidemiologist Sherine Gabriel, M.D. "With this study, we've now applied a mathematical model that shows consistency between our observed mortality rates and our understanding of the concept of accelerated aging."
Dr. Gabriel explains that new knowledge about this acceleration factor also underscores the need for people with RA to be aware of their increased health risks and to seek medical care that addresses their total health.
"Because rheumatoid arthritis is chronic and can be so consuming, patients and their doctors sometimes pay less attention to other issues, like cardiovascular health," notes Dr. Gabriel. "Studies like these remind us that early diagnosis and intervention are extremely important for these patients."
Future research likely will focus on establishing a closer link between the Mayo findings and laboratory studies of cellular aging.
The Mayo Clinic research team also included: Cynthia Crowson and Hilal Maradit Kremers, M.D. The work was supported by grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases.
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