Recent research findings indicate that running as a habitual exercise at any stage in life does not increase the risk of developing knee osteoarthritis (OA), and may in fact help protect against development of the disease. According to a news release from the American College of Rheumatology, the findings were presented at its Annual Meeting in Boston.

The study authors state in the release that previous research regarding a potential connection between running and knee OA focused on elite male runners, and as such, those findings may not apply well to the general population. The concern that regular running might contribute to knee OA focuses on the chronic, mechanical overloading of the knee joints, which might be damaging. However, the release says, runners typically have a lower body mass index (BMI), a factor that helps protect against developing knee OA.

Grace Hsiao-Wei Lo, MD, MSc, Baylor College of Medicine, and a lead author of the study, explains that recent CDC guidelines recommend all adults participate in regular physical activity. The recommendation reflects definitive evidence, she says, that increased physical activity is linked to reduced cardiovascular events and mortality.

“However, the influence of these physical activities on knee OA is unclear. Since running is a common leisure physical activity that involves repetitive loading, which could be harmful to the joint, I was particularly interested in studying how habitual running relates to the development of knee OA,” Lo adds.

In an effort to investigate whether habitual running would increase knee OA risk for the general population, the researchers reportedly used data from a multicenter observational study known as the Osteoarthritis Initiative (OAI). The release notes that among the 2,683 participants, 56% were female, and the mean age was 64.5 and the mean BMI was 28.6. A total of 29% of the participants noted that they ran at some time in their lives.

The release states that participants underwent knee x-rays, were given symptom assessments, and were asked to complete the Lifetime Physical Activity Questionnaire (LPAQ), identifying the top three most frequently performed physical activities that they performed throughout life at different age ranges. Age ranges include aged 12 to 18, 19 to 34, 35 to 49, and 50 years old or older.

During the OAI 48-month visit, knee x-rays were taken and scored for evidence of radiographic OA using the Kellgren-Lawrence (KL) grade scale. Participants with KL grades of two or higher were considered as having radiographic OA (ROA). The release notes that the researchers also measured whether participants had frequent knee pain at their 48-month visit. Participants were considered to have symptomatic OA (SOA) if they had at least one knee with both ROA and frequent knee pain. Individuals with a total knee replacement were classified as having frequent knee pain, ROA, and SOA.

Once all the data was collected, the release reports that runners, regardless of the age when they ran, had a lower prevalence of knee pain, ROA, and SOA than non-runners. For individuals who had run at any time in their lives, the results indicate 22.8% had SOA compared to 29.8% of non-runners. The individuals with the lowest BMI scores were the most likely to report being habitual runners, according to the researchers.

The researchers ultimately conclude in the release that regular running, even at a non-elite level, not only does not increase the risk of developing knee OA, but may protect against it.

Lo emphasizes however, that while this does not address the question of whether or not running is harmful to individuals with pre-existing knee OA, “in people who do not have knee OA, 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.”

[Source(s): Science Daily, American College of Rheumatology (ACR)]