Background/Purpose

Controversy exists regarding whether habitual running is beneficial versus harmful to the knee.  Chronic mechanical overloading could potentially physically damage structures within the knee.  Alternatively, runners have a lower body mass index (BMI), protective of knee osteoarthritis (OA).  Most existing studies evaluating running and knee osteoarthritis (OA) have focused on elite male athletes, not generalizable to most of the population.  Therefore, we aimed to evaluate the relationship of habitual running with symptomatic knee OA in the Osteoarthritis Initiative (OAI), a cohort recruited from the community not based on elite running status.    

Methods

This is a cross-sectional study of OAI participants with knee x-ray readings, symptom assessments, and completed surveys on lifetime physical activity. At the 96-month visit, a modified version of the Lifetime Physical Activity Questionnaire (LPAQ) asked participants to identify the top 3 most frequently performed physical activities (≥ 20 times in life) from ages 12 – 18, 19 – 34, 35 – 49 and >50 years old.  Those indicating running as an activity were defined as a runner in that time period.  Running at any time in life included runners from all time periods. Posterior-Anterior semi-flexed knee radiographs were obtained at OAI 48-month visit and scored for Kellgren-Lawrence (KL) grade (0-4).  Radiographic OA (ROA) was defined as KL ≥ 2.   Frequent knee pain within a person required at least one knee have frequent knee pain at the OAI 48-month visit. Symptomatic radiographic OA (SOA) required that at least one knee had both ROA and frequent knee pain.  Anyone with a total knee replacement was classified as having SOA. 

We performed logistic regression analyses where the predictor was running any time in life and running in the specific age ranges.  The outcomes were ROA, frequent knee pain, and SOA; adjusted analyses included covariates age, sex and BMI. 

Results

2439 participants were included, 55% were female, mean age was 64.7 (9.0) years and BMI was 28.5 (4.9) kg/m².  28% ran at some time in their lives; of those, 49%, 31%, 15% and 5% identified running in 1, 2, 3, and 4 of the time periods respectively.  From lowest to highest BMI tertile, 35%, 28%, and 24% were runners at any time in life. 

Table: Odds Ratios of Prevalent Symptomatic Knee Osteoarthritis (SOA) for Runners compared to Non-Runners.
Running Time Period	Prevalence of SOA	Unadjusted Odds Ratios	Adjusted Odds Ratios*
Any time in Life
No (n = 1528)	29.3%	Referent	Referent
Yes (n = 626)	22.7%	0.84 (0.76 – 0.94)	0.89 (0.79 – 1.00)
Ages 12 – 18 years old
No (n = 1924)	27.7%	Referent	Referent
Yes (n = 212)	23.6%	0.81 (0.58 – 1.12)	0.94 (0.66 – 1.34)
Ages 19 – 34 years old
No (n = 1806)	28.3%	Referent	Referent
Yes (n = 332)	22.0%	0.71 (0.54 – 0.94)	0.78 (0.58 – 1.05)
Ages 35 – 49 years old
No (n = 1794)	28.2%	Referent	Referent
Yes (n = 374)	22.5%	0.74 (0.56 – 0.97)	0.85 (0.63 – 1.13)
Ages > 50 years old
No (n = 1881)	28.2%	Referent	Referent
Yes (n = 221)	22.2%	0.73 (0.52 – 1.01)	0.85 (0.60 – 1.20)
*Adjusted for Age, Sex, and BMI.

For outcomes of frequent knee pain and ROA, the results were similar to that of SOA. 

Conclusion

Our findings suggest an exposure to non-elite running at any time in life is not associated with a higher odds of prevalent ROA, knee pain, and SOA.  Those with the lowest BMI were most likely to identify running as a habitual activity.  These findings were observed in a cohort recruited from the community not based on elite running status making these findings potentially more applicable to a broader population.  Non-elite running at any time in life does not appear detrimental, and may be protective of SOA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/habitual-running-any-time-in-life-is-not-detrimental-and-may-be-protective-of-symptomatic-knee-osteoarthritis-data-from-the-osteoarthritis-initiative/