Is Lifelong Knee Joint Force from Work, Home, and Sport Related to Knee Osteoarthritis?

Purpose. To investigate the association of cumulative lifetime knee joint force on the risk of self-reported medically-diagnosed knee osteoarthritis (OA). Methods. Exposure data on lifetime physical activity type (occupational, household, sport/recreation) and dose (frequency, intensity, duration) were collected from 4,269 Canadian men and women as part of the Physical Activity and Joint Heath cohort study. Subjects were ranked in terms of the “cumulative peak force index”, a measure of lifetime mechanical knee force. Multivariable logistic regression was conducted to obtain adjusted effects for mean lifetime knee force on the risk of knee OA. Results. High levels of total lifetime, occupational and household-related force were associated with an increased in risk of OA, with odds ratio’s ranging from approximately 1.3 to 2. Joint injury, high BMI and older age were related to risk of knee OA, consistent with previous studies. Conclusions. A newly developed measure of lifetime mechanical knee force from physical activity was employed to estimate the risk of self-reported, medically-diagnosed knee OA. While there are limitations, this paper suggests that high levels of total lifetime force (all domains combined), and occupational force in men and household force in women were risk factors for knee OA

The Effect of Disease Site (Knee, Hip, Hand, Foot, Lower Back or Neck) on Employment Reduction Due to Osteoarthritis

Osteoarthritis (OA) has a significant impact on individuals' ability to work. Our goal was to investigate the effects of the site of OA (knee, hip, hand, foot, lower back or neck) on employment reduction due to OA (EROA).This study involved a random sample of 6,000 patients with OA selected from the Medical Service Plan database in British Columbia, Canada. A total of 5,491 were alive and had valid addresses, and of these, 2,259 responded (response rate = 41%), from which 2,134 provided usable data. Eligible participants were 19 or older with physician diagnosed OA based on administrative data between 1992 and 2006. Data of 688 residents were used (mean age 62.1 years (27 to 86); 60% women). EROA had three levels: no reduction; reduced hours; and total cessation due to OA. The (log) odds of EROA was regressed on OA sites, adjusting for age, sex, education and comorbidity. Odds ratios (ORs) represented the effect predicting total cessation and reduced hours/total cessation. The strongest effect was found in lower back OA, with OR = 2.08 (95% CI: 1.47, 2.94), followed by neck (OR = 1.59; 95% CI: 1.11, 2.27) and knee (OR = 1.43; 95% CI: 1.02, 2.01). We found an interaction between sex and foot OA (men: OR = 1.94; 95% CI: 1.05, 3.59; women: OR = 0.89; 95% CI = 0.57, 1.39). No significant effect was found for hip OA (OR = 1.33) or hand OA (OR = 1.11). Limitations of this study included a modest response rate, the lack of an OA negative group, the use of administrative databases to identify eligible participants, and the use of patient self-reported data.After adjusting for socio-demographic variables, comorbidity, and other OA disease sites, we find that OA of the lower back, neck and knee are significant predictors for EROA. Foot OA is only significantly associated with EROA in males. For multi-site combinations, ORs are multiplicative. These findings may be used to guide resource allocation for future development/improvement of vocational rehabilitation programs for site-specific OA

Validation of Administrative Osteoarthritis Diagnosis Using a Clinical and Radiological Population-Based Cohort

Objectives. The validity of administrative osteoarthritis (OA) diagnosis in British Columbia, Canada, was examined against X-rays, magnetic resonance imaging (MRI), self-report, and the American College of Rheumatology criteria. Methods. During 2002–2005, 171 randomly selected subjects with knee pain aged 40–79 years underwent clinical assessment for OA in the knee, hip, and hands. Their administrative health records were linked during 1991–2004, in which OA was defined in two ways: (AOA1) at least one physician’s diagnosis or hospital admission and (AOA2) at least two physician’s diagnoses in two years or one hospital admission. Sensitivity, specificity, and predictive values were compared using four reference standards. Results. The mean age was 59 years and 51% were men. The proportion of OA varied from 56.3 to 89.7% among men and 77.4 to 96.4% among women according to reference standards. Sensitivity and specificity varied from 21 to 57% and 75 to 100%, respectively, and PPVs varied from 82 to 100%. For MRI assessment, the PPV of AOA2 was 100%. Higher sensitivity was observed in AOA1 than AOA2 and the reverse was true for specificity and PPV. Conclusions. The validity of administrative OA in British Columbia varied due to case definitions and reference standards. AOA2 is more suitable for identifying OA cases for research using this Canadian database

Risk of Type 2 Diabetes among Osteoarthritis Patients in a Prospective Longitudinal Study

Objectives. Our aim was to determine the risk of diabetes among osteoarthritis (OA) cases in a prospective longitudinal study. Methods. Administrative health records of 577,601 randomly selected individuals from British Columbia, Canada, from 1991 to 2009, were analyzed. OA and diabetes cases were identified by checking physician’s visits and hospital records. From 1991 to 1996 we documented 19,143 existing OA cases and selected one non-OA individual matched by age, sex, and year of administrative records. Poisson regression and Cox proportional hazards models were fitted to estimate the effects after adjusting for available sociodemographic and medical factors. Results. At baseline, the mean age of OA cases was 61 years and 60.5% were women. Over 12 years of mean follow-up, the incidence rate (95% CI) of diabetes was 11.2 (10.90–11.50) per 1000 person years. Adjusted RRs (95% CI) for diabetes were 1.27 (1.15–1.41), 1.21 (1.08–1.35), 1.16 (1.04–1.28), and 0.99 (0.86–1.14) for younger women (age 20–64 years), older women (age ≥ 65 years), younger men, and older men, respectively. Conclusion. Younger adults and older women with OA have increased risks of developing diabetes compared to their age-sex matched non-OA counterparts. Further studies are needed to confirm these results and to elucidate the potential mechanisms

Risk of Type 2 Diabetes among Osteoarthritis Patients in a Prospective Longitudinal Study

Objectives. Our aim was to determine the risk of diabetes among osteoarthritis (OA) cases in a prospective longitudinal study. Methods. Administrative health records of 577,601 randomly selected individuals from British Columbia, Canada, from 1991 to 2009, were analyzed. OA and diabetes cases were identified by checking physician's visits and hospital records. From 1991 to 1996 we documented 19,143 existing OA cases and selected one non-OA individual matched by age, sex, and year of administrative records. Poisson regression and Cox proportional hazards models were fitted to estimate the effects after adjusting for available sociodemographic and medical factors. Results. At baseline, the mean age of OA cases was 61 years and 60.5% were women. Over 12 years of mean follow-up, the incidence rate (95% CI) of diabetes was 11.2 (10.90-11.50) per 1000 person years. Adjusted RRs (95% CI) for diabetes were 1.27 (1.15-1.41), 1.21 (1.08-1.35), 1.16 (1.04-1.28), and 0.99 (0.86-1.14) for younger women (age 20-64 years), older women (age ≥ 65 years), younger men, and older men, respectively. Conclusion. Younger adults and older women with OA have increased risks of developing diabetes compared to their age-sex matched non-OA counterparts. Further studies are needed to confirm these results and to elucidate the potential mechanisms

Occurrence of Radiographic Osteoarthritis of the Knee and Hip Among African Americans and Whites: A Population-Based Prospective Cohort Study

To compare the incidence and progression of radiographic osteoarthritis (OA) in the knee and hip among African Americans and whites

Efficacy of glucosamine sulfate in knee osteoarthritis : a randomized controlled discontinuation trial

Objectives: The primary objective of this study was to determine the clinical efficacy of glucosamine in knee OA in a randomized discontinuation trial. As a secondary objective, the effect of glucosamine on cartilage type II collagen degradation (CII) was evaluated. Methods: A multicenter 24-week randomized double-blind placebo-controlled glucosamine sulfate (GS) discontinuation trial was conducted. Subjects were included if they met the American College of Rheumatology criteria for knee OA, had osteophytes on x-ray, were current users of glucosamine, and had had at least moderate relief of knee pain after starting glucosamine. Subjects received GS at the same dose as prior to the study or placebo (PL) at an equivalent dose. Treatment was continued for 24 weeks or until disease flare. The primary outcome was the proportion of subjects with disease flare in the two groups. Secondary outcomes included time to flare, severity of flare, Western Ontario and McMaster Universities OA index (WOMAC) scores, analgesic medication use and CII degradation markers. Results: The intent-to-treat analysis included 137 subjects (71 GS, 66 PL), aged 40-88 yrs (mean 64) with median baseline WOMAC pain on walking of 13mm (range 0-78mm) and median duration of GS use of 1.5 yrs (range 0 . 1 - 7 yrs). The proportion of subjects who developed a flare in the PL and GS groups was 42% and 45%, respectively (95% confidence interval [CI], -19%, 14%; p=0.76). After adjustment for sex and OA radiographic severity at baseline, the risk of disease flare was similar in the two groups (Cox regression hazard ratio for GS group 0.81; 95% CI 0.47, 1.40; p=0.45). Similarly, no significant differences were seen between treatment groups in the severity of flare, WOMAC scores, analgesic medication use and CII degradation markers. Conclusion: In knee OA subjects with moderate to marked subjective improvement with prior glucosamine use, this study provides no evidence of benefit from the continued use of glucosamine sulfate over 6 months. No statistically significant effect of glucosamine sulfate on type II collagen degradation was demonstrated.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofGraduat

Association between Cumulative Joint Loading from Occupational Activities and Knee Osteoarthritis

Objective: To determine the associations between cumulative occupational physical load (COPL) and three definitions of knee osteoarthritis. Methods: Cross-sectional analyses were performed from two 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 (i.e., QCOPL). Radiographic osteoarthritis (ROA) and symptomatic osteoarthritis (SOA) were defined by Kellgren Lawrence grade >2, with SOA also including pain. Magnetic resonance imaging osteoarthritis (MRIOA) was defined using criteria by Hunter and associates. Logistic regression, adjusted with population weights, examined the associations between QCOPL and ROA, SOA, and MRI-OA, respectively, after controlling for covariates and two-way interactions. Results: Participants were on average 58.5 (SD=11.0) years old with a BMI of 26.3 (SD=4.7). 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 (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; QCOPL3: 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.) Conclusion: Occupational activity is associated with knee OA with dose-response relationships observed in SOA and MRI-OA.Medicine, Faculty ofMedicine, Department ofPhysical Therapy, Department ofPopulation and Public Health (SPPH), School ofRheumatology, Division ofReviewedFacultyGraduat

Reducing the burden of low back pain: results from a new microsimulation model

Background Low back pain (LBP) causes the highest morbidity burden globally. The purpose of the present study was to project and compare the impact of three strategies for reducing the population health burden of LBP: weight loss, ergonomic interventions, and an exercise program. Methods We have developed a microsimulation model of LBP in Canada using a new modeling platform called SimYouLate. The initial population was derived from Cycle 1 (2001) of the Canadian Community Health Survey (CCHS). We modeled an open population 20 years of age and older. Key variables included age, sex, education, body mass index (BMI), type of work, having back problems, pain level in persons with back problems, and exercise participation. The effects of interventions on the risk of LBP were obtained from the CCHS for the effect of BMI, the Global Burden of Disease Study for occupational risks, and a published meta-analysis for the effect of exercise. All interventions lasted from 2021 to 2040. The population health impact of the interventions was calculated as a difference in years lived with disability (YLDs) between the base-case scenario and each intervention scenario, and expressed as YLDs averted per intervention unit or a proportion (%) of total LBP-related YLDs. Results In the base-case scenario, LBP in 2020 was responsible for 424,900 YLDs in Canada and the amount increased to 460,312 YLDs in 2040. The effects of the interventions were as follows: 27,993 (95% CI 23,373, 32,614) YLDs averted over 20 years per 0.1 unit change in log-transformed BMI (9.5% change in BMI) among individuals who were overweight and those with obesity, 19,416 (16,275, 22,557) YLDs per 1% reduction in the proportion of workers exposed to occupational risks, and 26,058 (22,455, 29,661) YLDs averted per 1% increase in the proportion of eligible patients with back problems participating in an exercise program. Conclusions The study provides new data on the relationship between three types of interventions and the resultant reductions in LBP burden in Canada. According to our model, each of the interventions studied could potentially result in a substantial reduction in LBP-related disability.Medicine, Faculty ofNon UBCMedicine, Department ofPhysical Therapy, Department ofPopulation and Public Health (SPPH), School ofReviewedFacult

Open MRI validation of a hip model driven with subject-specific motion capture data in predicting anterior femoroacetabular clearance

Background Cam and/or pincer morphologies (CPM) are potential precursors to hip osteoarthritis (OA) and important contributors to non-arthritic hip pain. However, only some CPM hips develop OA and/or pain, and it is not clear why. Anterior impingement between the femoral head/neck contour and acetabular rim during motion is a proposed pathomechanism. Understanding how activity and deformity combine to produce impingement may shed light on the causes of hip degeneration/pain. The objective of this study was to determine the accuracy of a subject-specific hip model driven by subject-specific motion data in predicting anterior impingement. Methods We recruited 22 participants with CPM (both with and without pain) and 11 controls. We collected subject-specific 3D kinematics during squatting and sitting flexion, adduction, and internal rotation (FADIR) (an active and a passive maneuver, respectively, proposed to provoke impingement). We then developed 3D subject-specific hip models from supine 3T hip MRI scans that predicted the beta angle (a measure of anterior femoroacetabular clearance) for each frame of acquired kinematics. To assess the accuracy of these predictions, we measured the beta angle directly in the final position of squatting and sitting FADIR using open MRI scans. We selected the frame of motion data matching the static imaged posture using the least-squares error in hip angles. Model accuracy for each subject was calculated as the absolute error between the open MRI measure of beta and the model prediction of beta at the matched time frame. To make the final model accuracy independent of goodness of match between open MRI position and motion data, a threshold was set for least-squares error in hip angles, and only participants that were below this threshold were considered in the final model accuracy calculation, yielding results from 10 participants for squatting and 7 participants for sitting FADIR. Results For squatting and sitting FADIR, we found an accuracy of 1.1°(0.8°) and 1.3°(mean (SD), and root mean squared error, respectively) and 0.5°(0.3°) and 0.6°, respectively. Conclusion This subject-specific hip model predicts anterior femoroacetabular clearance with an accuracy of about 1°, making it useful to predict anterior impingement during activities measured with motion analysis.Medicine, Faculty ofNon UBCBiomedical Engineering, School ofMedicine, Department ofOrthopaedic Surgery, Department ofPhysical Therapy, Department ofApplied Science, Faculty ofReviewedFacultyResearche