Background: Existing evidence on whether marathon running contributes to hip and knee arthritis is inconclusive. Our aim was to describe hip and knee health in active marathon runners, including the prevalence of pain, arthritis, and arthroplasty, and associated risk factors.
Methods: A hip and knee health survey was distributed internationally to marathon runners. Active marathoners who completed ≥5 marathons and were currently running a minimum of 10 miles per week were included (n = 675). Questions assessed pain, personal and family history of arthritis, surgical history, running volume, personal record time, and current running status. Multivariable analyses identified risk factors for pain and arthritis. Arthritis prevalence in U.S. marathoners was compared with National Center for Health Statistics prevalence estimates for a matched group of the U.S.
Results: Marathoners (n = 675) with a mean age of 48 years (range, 18 to 79 years) ran a mean distance of 36 miles weekly (range, 10 to 150 miles weekly) over a mean time of 19 years (range, 3 to 60 years) and completed a mean of 76 marathons (range, 5 to 1,016 marathons). Hip or knee pain was reported by 47%, and arthritis was reported by 8.9% of marathoners. Arthritis prevalence was 8.8% for the subgroup of U.S. marathoners, significantly lower (p < 0.001) than the prevalence in the matched U.S. population (17.9%) and in subgroups stratified by age, sex, body mass index (BMI), and physical activity level (p < 0.001). Seven marathoners continued to run following hip or knee arthroplasty. Age and family and surgical history were independent risk factors for arthritis. There was no significant risk associated with running duration, intensity, mileage, or the number of marathons completed (p > 0.05).
Conclusions: Age, family history, and surgical history independently predicted an increased risk for hip and knee arthritis in active marathoners, although there was no correlation with running history. In our cohort, the arthritis rate of active marathoners was below that of the general U.S.
Population: Longitudinal follow-up is needed to determine the effects of marathon running on developing future hip and knee arthritis.
Level of evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.