AT THE ACR ANNUAL MEETING
BOSTON (FRONTLINE MEDICAL NEWS) – A history of current or past running did not contribute to a higher odds of developing knee osteoarthritis and may even have a slight protective effect, researchers found in a cross-sectional study of participants in the Osteoarthritis Initiative .
“Although this study does not address the question of whether or not running is harmful in people who do have preexisting knee OA [osteoarthritis], among people who do not have knee OA, [the study indicates that] there is no reason to restrict participation in habitual running at any time in life from the perspective that it does not appear to be harmful to the knee joint,” lead author Dr. Grace Hsiao-Wei Lo said at a press briefing at the annual meeting of the American College of Rheumatology.
Physical activities guidelines from the Centers for Disease Control and Prevention recommend that adults get at least 75 minutes per week of physical activity at a vigorous intensity, which includes running or jogging, noted Dr. Lo of the section of immunology, allergy, and rheumatology at Baylor College of Medicine, Houston.
The study, which is among the first to examine the potential relationship between running and OA in a population-based study of nonelite or high-level runners, included 2,683 participants (44% male) with a mean age of 64 years and mean body-mass index (BMI) of 28 kg/m2. The investigators found that 29% self-identified as runners as some point in their life up to their inclusion into study, with running history occurring in 49% of those aged older than 50 years, 31% in those aged 35-49 years, 15% in those aged 19-34 years, and 9% in those aged 12-18 years. Patients were identified as runners if they listed it as one of their top three activities during those periods. Runners were slightly younger than the overall population with a mean age of 62 years and were more often male (62%). Nonrunners had a mean age of 65 years and were less often male (36%). BMI did not differ between the two.
Knee pain was significantly less prevalent in runners than in nonrunners (35% vs. 42%, respectively), and runners were 13% less likely to have knee pain (odds ratio, 0.87). The relationship did not change after controlling for age, sex, and BMI.
Radiographic knee OA with a Kellgren-Lawrence grade of 2 or more also was significantly less common among runners than among nonrunners (54% vs. 60%), but the relationship was not significant after controlling for the same variables.
Symptomatic radiographic OA – defined as having at least one knee with both radiographic knee OA and frequent knee pain – occurred in 23% of runners and 30% of nonrunners. The significantly lower likelihood for runners to develop symptomatic knee OA than non-runners (OR, 0.83) was slightly attenuated after controlling for age, sex, and BMI, but remained statistically significant.
“When we did look at each individual age range, the results were very similar. Some of the results were no longer statistically significant, but the results were generally in the same direction,” Dr. Lo noted.
Previous studies that have examined the relationship between running and the development of knee OA have been limited in their generalizability to the general population because of the inclusion of elite runners and those with a high level of running as well as small sample size, Dr. Lo said. Self-selection as runners is an important limitation of this cross-sectional, observational study because “there’s always the possibility that people stopped running because they developed knee symptoms,” she said.
Dr. Lo said that her work on the study was supported by a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases. None of the other authors had disclosures.
