Association Between Cumulative Joint Loading From Occupational Activities and Knee Osteoarthritis
Article first published online: 24 SEP 2013
Copyright © 2013 by the American College of Rheumatology
Arthritis Care & Research
Volume 65, Issue 10, pages 1634–1642, October 2013
How to Cite
Ezzat, A. M., Cibere, J., Koehoorn, M. and Li, L. C. (2013), Association Between Cumulative Joint Loading From Occupational Activities and Knee Osteoarthritis. Arthritis Care Res, 65: 1634–1642. doi: 10.1002/acr.22033
- Issue published online: 24 SEP 2013
- Article first published online: 24 SEP 2013
- Accepted manuscript online: 22 APR 2013 03:05PM EST
- Manuscript Accepted: 11 APR 2013
- Manuscript Received: 17 JAN 2013
- Canadian Institutes of Health Research
- Canadian Arthritis Network
- The Arthritis Society of Canada
- Centocor Research & Development Inc.
- Physiotherapy Foundation of Canada (Dominion of Canada Scholarship)
- The Arthritis Society Investigator Award
- Michael Smith Foundation for Health Research
- Michael Smith Foundation for Health Research and a Canadian Institutes of Health Research New Investigator Award
To determine the associations between cumulative occupational physical load (COPL) and 3 definitions of knee osteoarthritis (OA).
Cross-sectional analyses were performed from 2 population-based cohorts (n = 327). Eligible symptomatic participants were those with pain, aching, or discomfort in or around the knee on most days of a month at any time in the past and any pain in the past 12 months. Asymptomatic participants responded “no” to both knee pain questions. Self-reported COPL was calculated over each participant's lifetime and then categorized into quarters (QCOPL). Radiographic OA (ROA) and symptomatic OA (SOA) were defined by Kellgren/Lawrence grade ≥2, with SOA also including pain. Magnetic resonance imaging (MRI) OA was defined using criteria by Hunter et al. Logistic regression, adjusted with population weights, examined the associations between QCOPL and each of ROA, SOA, and MRI-OA after controlling for covariates and two-way interactions.
Participants had a mean ± SD age of 58.5 ± 11.0 years and a mean ± SD body mass index of 26.3 ± 4.7 kg/m2. Of those, 109 (33.3%) had ROA, 102 (31.2%) had SOA, and 131 (40.1%) had MRI-OA. Compared with QCOPL-1, increased odds of ROA were found for QCOPL-4 (odds ratio [OR] 3.15, 95% confidence interval [95% CI] 1.02–9.70) and QCOPL-3 (OR 4.19, 95% CI 1.55–11.34). Statistically significant relationships were found in SOA (QCOPL-4: OR 8.16, 95% CI 1.89–35.27; QCOPL-3: OR 5.73, 95% CI 1.36–24.12) and MRI-OA (QCOPL-4: OR 9.54, 95% CI 2.65–34.27; QCOPL-3: OR 9.04, 95% CI 2.65–30.88; QCOPL-2: OR 7.18, 95% CI 2.17–23.70).
Occupational activity is associated with knee OA, with dose-response relationships observed in SOA and MRI-OA.