UNC study finds 'alarming increase' in prevalence of chronic low back pain

February 10, 2009

The proportion of people suffering from long-term, impairing low back pain has more than doubled in North Carolina since the early 1990s, according to a new study.What’s more, researchers believe the increase may be indicative of a similar trend across the country. In the study, published in the Feb. 9, 2009, issue of the Archives of Internal Medicine, UNC researchers found that the prevalence of chronic, impairing low back pain in the state increased from 3.9 percent in 1992 to 10.2 percent in 2006. Increases were seen in both men and women, and across all ages and racial and ethnic groups. Dr. William Kalsbeek

Study co-authors include William D. Kalsbeek, PhD, professor, and Robert P. Agans, PhD, research associate, from the UNC Gillings School of Global Public Health’s biostatistics department.

“Considering the social and economic costs of chronic low back pain, these findings are alarming,” said the study’s principal investigator, Timothy S. Carey, MD, director of the Cecil G. Sheps Center for Health Services Research and Sarah Graham Kenan Professor in the departments of medicine and social medicine in the UNC School of Medicine. “Low back pain is the second most common cause of disability in the United States and a common reason for missing work.”

“People with chronic low back pain also use an enormous amount of health care,” said the study’s lead author, Janet K. Freburger, Ph.D., a research associate and fellow at the Sheps Center and a research scientist at the UNC Institute on Aging.

Carey and Freburger noted that more than 80 percent of Americans will experience an episode of low back pain at some time in their lives and that total costs of the condition are estimated at greater than $100 billion annually, with two-thirds of that due to decreased wages and productivity.

“Since the costs of back pain are rising, along with the number of cases, current treatments overall do not seem to be very effective,” Carey said.

The study is thought to be the first in the United States to use similar methods and a consistent definition of chronic low back pain to examine trends in the condition’s prevalence over time.

The new findings also provide a possible explanation for rising health-care costs associated with back problems.

Some researchers have concluded that increases in the use of health-care services for low back pain are due to people with low back pain seeking more care nowadays than in the past.

However, the UNC researchers say their data suggests that increased prevalence may be the primary factor driving those increases in service use and costs. That’s because the proportion of people in North Carolina who sought health care for chronic low back pain rose only moderately between 1992 and 2006 (from 73.1 percent to 84 percent), and the average number of visits to all providers remained similar.

The paper notes that until now, studies examining trends in the prevalence of chronic low back pain have been “severely lacking.”

“Discerning whether the prevalence of this condition is increasing and contributing to the increase in the use of health care services is vital for developing strategies to contain costs and improve care,” Freburger said.

Reasons for the increase in chronic low back pain are unclear, although possible causes include increasing rates of obesity, depression and awareness of the condition, the study said. The changing nature of the state’s workforce – with a decline in the percentage of manufacturing jobs and an increase in construction and service industry jobs over the time span concerned – may be another possible factor.

The study was conducted using a telephone survey of about 4,400 households in 1992 and 5,300 households in 2006. Individuals were considered to have chronic low back pain if they reported pain and activity limitations nearly every day for the past three months or if they reported more than 24 episodes of pain that limited their activity for one or more days in the past year.

The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Study co-authors include George M. Holmes, PhD, senior research fellow, Anne M. Jackman, research fellow, and Jane D. Darter, applications analyst, all with the UNC Sheps Center; Kalsbeek and Agans, from the UNC Gillings School of Global Public Health; Andrea S. Wallace, PhD, from the University of New Mexico-Albuquerque College of Nursing; and Liana D. Castel, PhD, from the department of general internal medicine at Vanderbilt University Medical Center, Nashville, Tenn.

UNC Gillings School of Global Public Health contact: Ramona DuBose, director of communications, (919) 966-7467 or ramona_dubose@unc.edu.