Environmental Factor, October 2008, National Institute of Environmental Health Sciences
Seminar Examines Aging and Arthritis
By Eddy Ball
One of North Carolina's leading authorities on the public health implications of arthritis was the guest lecturer at a seminar sponsored by the NIEHS Disability Advocacy Committee (DAC) on September 9 in the Rall Building D-250 conference room. Hosted by DAC Chair Alicia Moore, the talk by University of North Carolina (UNC) Professor Leigh Callahan, Ph.D., was titled "Aging and Arthritis - Quality of Life and Issues Related to Disability." Callahan's presentation explored the public health implications of the disease, possible links to environmental exposures and ways to help prevent onset or ameliorate symptoms.
One of the 90 UNC specialists who donate their time as part of the university's Carolina Speakers (http://carolinaspeakers.unc.edu/) program, Callahan is an associate professor of Medicine, Orthopaedics and Social Medicine at the UNC Thurston Arthritis Research Center. She has more than 20 years of experience in arthritis and health outcomes research, and served as an arthritis epidemiologist with the Centers for Disease Control and Prevention (CDC) prior to joining UNC. She spoke about what was until recently an underappreciated cause of disability. Callahan also took questions from an audience of some 20 NIEHS staffers on topics ranging from the possible contribution of hormones to the merits of alternative treatments.
As Callahan explained, arthritis is a public health concern that, in its more than 100 forms, affects more than 46.1 million adults in the United States - a number expected to increase to more than 67 million by 2030 as the population ages. Arthritis can significantly limit activity and impact quality of life, Callahan told the audience, "and it is the leading cause of partial or total disability for adults." According to the Arthritis Foundation, she added, the costs associated with arthritis total more than $128 billion each year.
Turning to the geographical distribution of arthritis, Callahan said that the varying rates in different parts of the country are probably related to obesity rates. However, she also observed that recent research, such as the Johnson County Osteoarthritis Project (http://www.med.unc.edu/tarc/research/jordan-team/jocooa) conducted by colleagues of hers at the Thurston Research Center, turned up possible links to environmental exposures that merit further investigation.
Selenium, for example, may be protective, and investigators in the Johnson County studies have observed associations of higher blood levels of lead with osteoarthritis biomarkers and knee severity. Callahan noted that there was also some suspicion that mercury, arsenic and cadmium may have an influence on disease severity.
Callahan pointed to non-modifiable risk factors for disease, including gender, age and genetic predisposition, and socioeconomic factors associated with higher rates of disease in certain groups and communities. She noted that the modifiable risk factors - sports and occupational joint injuries, infection, joint-straining occupations and, especially, excess weight - offer individuals ways to potentially influence disease onset, symptom severity and impact on quality of life.
According to Callahan, one study found that a weight loss of just 5.1 kilograms was associated with a reduction in risk of developing osteoarthritis over a ten-year period. Losing weight can also help people who already have arthritis, she added, because obesity leads to greater limitations and more rapid disease progression. She said that the risk of developing arthritis makes even more compelling the CDC recommendation of dietary changes and moderate intensity exercise for 30 minutes three times per week to help control weight gain.
Callahan concluded her presentation by acknowledging that Americans are beginning to pay more attention to arthritis with such policy forums and initiatives as Healthy People 2010, the National Arthritis Action Plan, the NC Arthritis Action Plan 2001 and the Bone and Joint Decade Proclamation.