Session Information
Date: Tuesday, November 7, 2017
Title: Osteoarthritis – Clinical Aspects Poster II: Observational and Epidemiological Studies
Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose:
Walking is recommended for those with knee OA (KOA). However, few studies have explored the association between walking and symptomatic OA, and conflicting data exists whether walking is beneficial or harmful to knee structure. Walking is a weight-bearing exercise and chronic mechanical overloading could physically damage knee structures. Alternatively, people who walk are likely to have a lower body mass index (BMI), which is protective of KOA. Therefore, we evaluated the relationship of history of walking with symptomatic KOA in the Osteoarthritis Initiative (OAI).
Methods:
This is a cross-sectional study of OAI participants with knee x-rays, symptom assessments, and lifetime physical activity. At the 96-month visit, a modified version of the Lifetime Physical Activity Questionnaire (LPAQ) asked participants about the number of times they walked for exercise from ages 12 – 18, 19 – 34, 35 – 49 and >50 years old. This information was used to create biologically meaningful groups based on walking history. The lowest group were people who did not walk for exercise. The highest group included the top one or two levels of walking. We pooled the number of times people walked from all time periods. PA 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 with the predictor of groups based walking history over a lifetime and in the specific age ranges. The outcomes were ROA, frequent knee pain, and SOA; adjusted analyses included covariates age, sex, and BMI at the 48-month visit and injury up to the 48-month visit.
Results:
2637 participants were included, 44% were male, mean age was 64.3 (8.9) years and BMI was 28.4 (4.9) kg/m2 at the 48 month visit. Walking for exercise increased with increasing age. The percentage of obesity by lifetime walker group (never walker to high level walker) was: 41%, 39%, 33%, and 30% respectively. Findings for frequent knee pain and ROA were similar for SOA.
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Table. Odds Ratios of Prevalent Symptomatic OA By Walking Level (lowest to highest).
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Walking Time Period
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Prev. of Frequent SOA |
Unadjusted Odds Ratios |
Adjusted Odds Ratios* |
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Walking over a lifetime
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Non-walker (n =493)
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31.2% |
Referent |
Referent |
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Low (n =694)
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26.7% |
0.80(0.62-1.03) |
0.85(0.65-1.10) |
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Middle (n = 711)
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29.8% |
0.94(0.72-1.20) |
1.03(0.79-1.34) |
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High (n = 708)
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23.2% |
0.66(0.51-0.86) |
0.74(0.57-0.97) |
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p for trend=0.01 |
p for trend=0.11 |
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Ages 12 – 18 years old
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Non-walker (n = 1512)
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28.4% |
Referent |
Referent |
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Low (n =434)
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27.7% |
0.97(0.76-1.22) |
1.00(0.78-1.28) |
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High (n = 660)
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25.2% |
0.85(0.69-1.05) |
0.85(0.69-1.06) |
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p for trend=0.13 |
p for trend=0.16 |
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Ages 19 – 34 years old
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Non-walker (n=1369)
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27.9% |
Referent |
Referent |
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Low (n = 355)
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27.0% |
0.96(0.74-1.25) |
1.00(0.76-1.32) |
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Middle (n = 412)
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27.7% |
0.99(0.77-1.26) |
1.02(0.79-1.32) |
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High (n = 470)
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26.1% |
0.92(0.72-1.16) |
0.94(0.74-1.21) |
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p for trend=0.5 |
p for trend=0.7 |
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Ages 35 – 49 years old
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Non-walker (n=1102)
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30.0% |
Referent |
Referent |
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Low (n = 470)
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28.9% |
0.95(0.75-1.20) |
1.02(0.80-1.32) |
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Middle (n = 415)
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25.3% |
0.79(0.61-1.02) |
0.84(0.64-1.10) |
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High (n = 619)
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23.1% |
0.70(0.56-0.88) |
0.76(0.60-0.96) |
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p for trend=0.001 |
p for trend=0.01 |
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Ages > 50 years old
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Non-walker (n =693)
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32.9% |
Referent |
Referent |
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Low (n =651)
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25.4% |
0.69(0.55-0.88) |
0.75(0.58-0.96) |
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Middle (n = 596)
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26.0% |
0.72(0.56-0.91) |
0.81(0.63-1.04) |
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High (n = 666)
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25.1% |
0.68(0.54-0.86) |
0.79(0.62-1.01) |
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p for trend=0.003 |
p for trend=0.09 |
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*Adjusted for age, sex, BMI, and prior knee injury.
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Conclusion:
Our findings suggest walking for exercise at any time in life is not associated with a higher odds of prevalent ROA, knee pain, and SOA later in life. Walking for exercise may be beneficial but this may be obscured due to confounding by indication. Because people self-select whether they walk, they may stop the activity because of knee symptoms. Walking for exercise was more common with increasing age and was inversely associated with obesity. Walking for exercise does not appear detrimental, and may be protective of SOA.
To cite this abstract in AMA style:
Lo GH, Driban JB, Kriska A, McAlindon TE, Souza R, Petersen NJ, Rockette-Wagner BJ, Eaton C, Hochberg M, Jackson RD, Kwoh CK, Nevitt MC, Suarez-Almazor M. History of Walking for Exercise Is Not Associated with More Symptomatic Knee Osteoarthritis: Data from the Osteoarthritis Initiative [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/history-of-walking-for-exercise-is-not-associated-with-more-symptomatic-knee-osteoarthritis-data-from-the-osteoarthritis-initiative/. Accessed .« Back to 2017 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/history-of-walking-for-exercise-is-not-associated-with-more-symptomatic-knee-osteoarthritis-data-from-the-osteoarthritis-initiative/