Moderate physical activity does not increase risk of knee osteoarthritis, study finds

Aug. 29, 2013
A new study finds that adults age 45 and older who engaged in moderate physical activity up to 2.5 hours per week did not increase their risk of developing knee osteoarthritis over a six-year follow-up period.

Study participants who engaged in the highest levels of physical activity – up to five hours per week – did have a slightly higher risk of knee osteoarthritis, but the difference was not statistically significant.

Dr. Joanne Jordan

Dr. Joanne Jordan

Those findings taken together are good news, said senior study author Joanne Jordan, MD, MPH, director of the UNC Thurston Arthritis Research Center. Jordan is also Joseph P. Archie Jr. Eminent Professor of Medicine and chief of the division of rheumatology, allergy and immunology in the UNC School of Medicine and adjunct professor of epidemiology in UNC’s Gillings School of Global Public Health.

“This study shows that engaging in physical activity at these levels is not going to put you at a greater risk of knee osteoarthritis,” Jordan said. “Furthermore, we found this held true no matter what a person’s race, sex or body weight is. There was absolutely no association between these factors and a person’s risk.”

Kamil Barbour, PhD, an epidemiologist and researcher at the Centers for Disease Control and Prevention (CDC) in Atlanta, is corresponding author of the study, published online Aug. 27 in the journal Arthritis Care & Research.

 “Moderate physical activities are those that produce some increase in heart rate or breathing, like rapid walking,” Barbour said. “Meeting physical activity recommendations through these simple activities is a great way to reduce [one’s] risk of heart disease, stroke, high blood pressure, diabetes and other diseases.”

The results are based on analysis of data collected from 1999 to 2010 as part of UNC’s long-running Johnston County Osteoarthritis Project,  a prospective, population-based study of knee, hip, hand and spine osteoarthritis and disability in African-Americans and Caucasians, ages 45 years and older. This project is funded by the CDC and the National Institute of Arthritis, Musculoskeletal and Skin Diseases (NIAMS), one of the National Institutes of Health (NIH).

This new analysis included data from 1,522 study participants and tested whether or not there was an association between meeting Department of Health and Human Services (HHS) guidelines for 150 minutes of physical activity per week and the development of knee osteoarthritis, as confirmed both by X-rays and the presence of knee pain or other symptoms.

The study’s findings support HHS recommendations and conclude that activities that amount to moderate weekly levels of physical activity – e.g., walking, conditioning exercises and household activities such as gardening or yard work – should continue to be encouraged.

Co-authors from the Gillings School are Bill Kalsbeek, PhD, professor, and Todd Schwartz, DrPH, research assistant professor, both in the School’s Department of Biostatistics. Other authors are Jordan Renner, MD, professor of radiology in the UNC School of Medicine, and from the CDC, Jennifer Hootman, PhD, Charles Helmick, MD, Louise Murphy, PhD, and Kristina Theis, MPH.

Gillings School of Global Public Health contact: David Pesci, director of communications, (919) 962-2600 or