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The association between running volume and knee osteoarthritis prevalence: A systematic review and meta-analysis
Abstract
There is conflicting evidence regarding whether regular running is associated with knee osteoarthritis prevalence. Previous evidence reports lower knee osteoarthritis prevalence in recreational runners compared with professionals (with a higher training volume) and controls (who have a lower training volume). The aim of this systematic review and meta-analysis was to determine if weekly running volume is associated with knee osteoarthritis prevalence. Four databases (PubMed, Web of Science, Scopus and SPORTDiscus) were searched from earliest record to November 2021. Included studies must i) recruit participants who ran regularly and recorded weekly running volume; ii) include a control group (running <8 km per week); iii) record knee osteoarthritis prevalence (either by radiological imaging or self-reported diagnosis from a doctor or physiotherapist). Study bias was assessed using the Newcastle-Ottawa Scale (NOS). Pooled effects were estimated using a random effects model. Odds ratios with 95% prediction and confidence intervals are reported. Nine observational case control studies with a total of 12,273 participants (1272 runners) were included in the meta-analysis. Most of the included studies were rated as having a very high (n = 2) or high (n = 3) risk of bias on the Newcastle Ottawa Scale. There was no difference in knee osteoarthritis prevalence between runners and controls (OR = 0.97, 95% CI = 0.56 to 1.68). Runners undertaking 8-32.1 km (OR = 1.17, 95% CI = 0.77 to 1.80), 32.2-48 km (OR = 1.04, 95% CI = 0.48 to 2.31) or > 48 km per week (OR = 0.62, 95% CI = 0.35 to 1.10) did not exhibit higher knee osteoarthritis prevalence compared with controls. It is unclear whether running volume is associated with increased knee osteoarthritis prevalence, future large-scale, high quality prospective studies are required.
... Epidemiological data indicate that approximately 10% of men and 18% of women aged over 60 are affected by OA, with knee involvement being among the most common and debilitating presentations (1). The disease not only results in chronic pain and functional impairment but also imposes a significant socio-economic burden, costing developed countries between 1% and 5% of their gross domestic product (GDP) annually (1,2). Traditionally, OA management has focused on symptomatic relief through pharmacologic interventions and, in advanced cases, surgical joint replacement. ...
... Traditionally, OA management has focused on symptomatic relief through pharmacologic interventions and, in advanced cases, surgical joint replacement. It is estimated that around 1.5% of individuals in the United Kingdom undergo surgical intervention for OA in their lifetime, predominantly total knee replacements (2). Clinically, OA diagnosis is established based on joint symptoms-mainly pain and stiffness-and confirmed through imaging modalities like X-rays, which reveal characteristic structural changes (3). ...
Background: Knee osteoarthritis (KOA) is a leading cause of musculoskeletal disability globally and is particularly prevalent among individuals engaged in physically demanding occupations. Industrial workers are at heightened risk due to repetitive movements, prolonged standing, and high mechanical workload. In Pakistan, limited research exists on the occupational burden of KOA, especially within industrial zones such as Hayatabad, Peshawar, where labor-intensive tasks are common. Objective: To determine the prevalence of knee osteoarthritis among industrial workers in the Industrial State of Hayatabad, Peshawar, Pakistan. Methods: A descriptive cross-sectional study was conducted over six months among 123 male industrial workers aged 18–60 years employed in three industries: Northern Bottling Company (PepsiCo), Saydon Natural Mineral Water, and Frontier Chemical Industry. A non-probability convenience sampling technique was used. Participants with systemic illness, physical disabilities, or those working double shifts were excluded. Data were collected using a structured questionnaire assessing knee pain and functional limitations. SPSS version 22 was used for data analysis to calculate frequencies and percentages. Results: Out of 123 participants, 87 workers (71.8%) reported symptoms consistent with KOA. The highest prevalence was observed in the 40–55 years age group, with 15 of 16 workers (96.29%) affected. KOA was most common among those employed for 15–20 years (100%), followed by those working over 20 years (94.73%). Workers performing 12-hour shifts showed a prevalence of 81.81% (7/9). Among those with KOA, 46.35% experienced mild pain, 38.82% reported pain primarily during standing, and 74.24% reported limitations in both sitting-to-standing transitions and lifting activities. Conclusion: KOA is highly prevalent among industrial workers in Hayatabad, particularly in those with prolonged work durations and standing positions. Targeted workplace ergonomics and early screening programs are essential to mitigate this occupational health burden.
... This study provided early evidence that repeated joint loading and impact stress could contribute to joint degradation and OA development. Similarly, a different study conducted a longitudinal analysis on long-distance runners and found that the cumulative effect of high mileage over years significantly increased knee OA risk, particularly among runners with other risk factors, such as a history of joint injuries or high BMI [14]. These findings are consistent with other research indicating that while moderate exercise may be safe, high-mileage running and similar high-impact activities elevate OA risk due to the repetitive stress applied to cartilage and surrounding joint tissues. ...
... Furthermore, Burfield et al. emphasized that long-distance running and similar repetitive highimpact activities can increase knee OA risk, especially in individuals with other risk factors like high BMI or previous joint injuries. Their findings suggest that cumulative exposure to joint stress -rather than isolated events -contributes to cartilage wear and, ultimately, OA development [14]. This effect is further supported by studies on professional athletes in sports like soccer and basketball, where OA prevalence is elevated due to the repetitive strain on joints from running, pivoting, and jumping [15]. ...
Introduction: Osteoarthritis (OA) is a prevalent degenerative joint disease, primarily affecting the elderly, with substantial impacts on mobility and quality of life. This review explores the role of physical activity in the development and progression of OA, analyzing both protective and adverse effects. Materials and Methods: A comprehensive literature review was conducted, analyzing studies from databases such as Google Scholar and PubMed on the effects of physical activity on OA. Analysis included longitudinal, cross-sectional, and interventional studies examining associations between physical activity levels, types of exercise, and OA onset and progression. Results: Moderate, low-impact physical activity, including walking, swimming, and cycling, tends to have a protective effect on joint health by promoting muscle strength and cartilage resilience. However, high-impact or excessive repetitive activities, such as intense running or heavy weightlifting, are associated with a higher risk of OA, particularly in weight-bearing joints like the knees and hips. Moreover, individual factors, such as age, BMI, and previous joint injuries, significantly mediate the impact of physical activity on OA risk Conclusions: Physical activity is a double-edged sword for OA; while moderate exercise may protect joint integrity, excessive high-impact activities may exacerbate OA risk, especially in predisposed individuals. Tailored exercise recommendations based on individual risk profiles could optimize benefits while minimizing OA development. Further research is needed to clarify dose-response relationships and to develop guidelines that balance the benefits of physical activity with OA prevention.
... Although some studies have shown a greater prevalence of hip and knee osteoarthritis in professional runners (13.3%) and sedentary individuals (10.2%) than in recreational runners (3.5%), it was not possible to determine if these associations were causative or confounded by other risk factors, such as previous injury [93]. There is currently no strong evidence that strenuous exercise increases the risk of osteoarthritis in healthy joints [94][95][96]. ...
Optimal loading involves the prescription of an exercise stimulus that promotes positive tissue adaptation, restoring function in patients undergoing rehabilitation and improving performance in healthy athletes. Implicit in optimal loading is the need to monitor the response to load, but what constitutes a normal response to loading? And does it differ among tissues (e.g., muscle, tendon, bone, cartilage) and systems? In this paper, we discuss the “normal” tissue response to loading schema and demonstrate the complex interaction among training intensity, volume, and frequency, as well as the impact of these training variables on the recovery of specific tissues and systems. Although the response to training stress follows a predictable time course, the recovery of individual tissues to training load (defined herein as the readiness to receive a similar training stimulus without deleterious local and/or systemic effects) varies markedly, with as little as 30 min (e.g., cartilage reformation after walking and running) or 72 h or longer (e.g., eccentric exercise-induced muscle damage) required between loading sessions of similar magnitude. Hyperhydrated and reactive tendons that have undergone high stretch–shorten cycle activity benefit from a 48-h refractory period before receiving a similar training dose. In contrast, bone cells desensitize quickly to repetitive loading, with almost all mechanosensitivity lost after as few as 20 loading cycles. To optimize loading, an additional dose (≤ 60 loading cycles) of bone-centric exercise (e.g., plyometrics) can be performed following a 4–8 h refractory period. Low-stress (i.e., predominantly aerobic) activity can be repeated following a short (≤ 24 h) refractory period, while greater recovery is needed (≥ 72 h) between repeated doses of high stress (i.e., predominantly anaerobic) activity. The response of specific tissues and systems to training load is complex; at any time, it is possible that practitioners may be optimally loading one tissue or system while suboptimally loading another. The consideration of recovery timeframes of different tissues and systems allows practitioners to determine the “normal” response to load. Importantly, we encourage practitioners to interpret training within an athlete monitoring framework that considers external and internal load, athlete-reported responses, and objective markers, to contextualize load–response data.
... INTRODUCTION: Regular running promotes longevity and is therefore a common part of exercise programs for people all over the world (Lee et al., 2017). However, a review study has shown conflicting evidence regarding whether the load associated with regular running affects the cartilage properties of large joints (Burfield et al., 2023). A recent, large, crosssectional study indicated that the frontal plane knee biomechanics of running was related to the knee collagen structure of the medial central femur cartilage T2 relaxation time, an early biomarker in the diagnosis and prediction of osteoarthritis (Nieminen et al., 2001) in healthy adults (Jandacka et al., 2024). ...
The purpose of this study was to investigate the association between maximal internal knee adduction moment (KAM) during running and the lateral knee cartilage structure in healthy adults. 1104 participants 18-65 years old participated in this study. Biomechanics of the lower extremity during running at the individual's self-preferred speed were recorded using motion capture system and force plates. A 1.5T MRI scan was used to determine T2 relaxation time of the lateral central femoral cartilage. When controlled for age, sex, running distance and morphological findings of a radiologist in a statistical model, the KAM (OR = 0.95, CI 0.80-1.12) did not significantly influence T2. The KAM did not appear to increase the odd of having a higher T2 relaxation time of the lateral central femoral cartilage indicating that this load may not be related to the deterioration of the collagen structure.
... These factors include joint integrity, joint load, genetic susceptibility, local inflammation, and the status of the muscles and fat around the knee joint [11,12]. Currently, there are multiple explanations for the pathogenesis of KOA, including metabolic inflammation, chondrocyte apoptosis and autophagy, synovial inflammation, and cytokine theories [13][14][15]. ...
Mechanosensitive ion channel Piezo1 is known to mediate a variety of inflammatory pathways and is also involved in the occurrence and development of many orthopedic diseases. Although its role in the inflammatory mechanism of knee osteoarthritis (KOA) has been reported, a systematic explanation is yet to be seen. This article aims to summarize the role of inflammatory responses in the pathogenesis of KOA and elucidate the mechanism by which the Piezo1-mediated inflammatory response contributes to the pathogenesis of KOA, providing a theoretical basis for the prevention and treatment of knee osteoarthritis. The results indicate that in the mechanism leading to knee osteoarthritis, Piezo1 can mediate the inflammatory response through chondrocytes and synovial cells, participating in the pathological progression of KOA. Piezo1 has the potential to become a new target for the prevention and treatment of this disease. Additionally, as pain is one of the most severe manifestations in KOA patients, the inflammatory response mediated by Piezo1, which causes the release of inflammatory mediators and pro-inflammatory factors leading to pain, can be further explored.
... Knee OA is a knee joint disease accompanied by chronic pain, mobility limitations, and an increased risk of falls [2]. Knee osteoarthritis is a chronic disease with long-term symptoms and structural changes, including articular cartilage disintegration, subchondral bone sclerosis, and structural changes in all soft tissues surrounding the knee joint [3][4][5]. As a result, knee OA negatively affects the patient's quality of life due to decreased muscle strength, physical performance, range of joint motion, and physical performance [6]. ...
Knee Osteoarthritis (OA) is one of the most common joint diseases that may cause physical disability associated with a significant personal and socioeconomic burden. X-ray imaging is the cheapest and most common method to detect Knee (OA). Accurate classification of knee OA can help physicians manage treatment efficiently and slow knee OA progression. This study aims to classify knee OA X-ray images according to anatomical types, such as uni or bicompartmental. The study proposes a deep learning model for classifying uni or bicompartmental knee OA based on redefined residual learning with CNN. The proposed model was trained, validated, and tested on a dataset containing 733 knee X-ray images (331 normal Knee images, 205 unicompartmental, and 197 bicompartmental knee images). The results show 61.81% and 68.33% for accuracy and specificity, respectively. Then, the performance of the proposed model was compared with different pre-trained CNNs. The proposed model achieved better results than all pre-trained CNNs.
... Regular running is used by many people around the world as an exercise mode that helps in the prevention of chronic disease and premature mortality (1). However, there is still conflicting evidence of whether the load associated with regular running affects the cartilage properties of large joints (2) such as in knee osteoarthritis (OA). The prevalence of knee OA is greater in females, the elderly and obese individuals (3). ...
Purpose
The purpose of this study was to determine whether regular running distance and biomechanics are related to medial central femur cartilage (MCFC) structure.
Methods
The cross-sectional study sample consisted of 1164 runners and non-runners aged 18-65 years. Participants completed questionnaires on physical activity and their running history. We performed quantitative magnetic resonance imaging of knee cartilage - T2 relaxation time (T2) mapping (high T2 indicate cartilage degeneration), and a running biomechanical analysis using a 3-D motion capture system. A 14-day monitoring of the physical activity was conducted.
Results
Those aged 35-49 years were at a 84% higher odds of having MCFC T2 in the highest level (85th percentile, P < 0.05) compared to youngest adults indicating that MCFC structures may be altered with ageing. Being male was associated with a 34% lower odds of having T2 at the highest level ( P < 0.05) compared to females. Non-runners and runners with the highest weekly running distance were more likely to have a high T2 compared to runners with running distance of 6-20 km per week ( P < 0.05). In addition, the maximal knee internal adduction moment was associated with a 19% lower odds of having T2 at the highest level ( P < 0.05).
Conclusions
Female compared to males and a middle-aged cohort compared to the younger cohort appeared to be associated with the degeneration of MCFC structures. Runners who ran 6-20 km/week were associated with a higher quality of their MCFC compared to highly active individuals and non-runners. Knee frontal plane biomechanics was related to MCFC structure indicating a possibility of modifying the medial knee collagen fibril network through regular running.
Excessive mechanical overloading of articular cartilage caused by excessive exercise or severe trauma is considered a critical trigger in the development of osteoarthritis (OA). However, the available clinical theranostic molecular targets and underlying mechanisms still require more elucidation. Here, we aimed to examine the possibility that bone morphogenetic proteins (BMPs) serve as molecular targets in rat cartilages and human chondrocytes under conditions of excessive mechanical overloading. Two rat models involving high‐intensity running training and surgery for destabilization of medial meniscus, along with a cell model subjected to cyclic tensile strain, were established to simulate and investigate excessive mechanical overloading effects on cartilages/chondrocytes. We employed various methods, including immunohistochemistry, real‐time polymerase chain reaction, western blot analysis, and enzyme‐linked immunosorbent assay, to evaluate the expression, secretion, phosphorylation, and nuclear translocation of mRNA/proteins in cartilages and chondrocytes. Our findings revealed a simultaneous upregulation of BMP‐2 and downregulation of BMP‐4 in degenerated and inflamed cartilages and chondrocytes under excessive mechanical overloading. Furthermore, toll‐like receptor 2 and nuclear factor kappa B‐p50/p65 subunits signaling were identified as regulators governing this distinct expression pattern. Treatment with recombinant BMP‐2 and/or BMP‐4 proteins significantly ameliorated cartilage degeneration and chondrocyte inflammation induced by excessive mechanical overloading. These results strongly suggest that BMP‐2 upregulation and BMP‐4 downregulation might represent mechanisms for self‐rescue and degeneration in damaged cartilage/chondrocytes, respectively. Our findings advance new insights that BMP‐2/‐4 might be potential molecular targets for excessive mechanical overloading‐caused OA development and should be taken into account in future clinical applications.
Magnetic resonance imaging (MRI) is increasingly used in the classification and evaluation of osteoarthritis (OA). Many studies have focused on knee OA, investigating the association between MRI-detected knee structural abnormalities and knee pain. Hip OA differs from knee OA in many aspects, but little is known about the role of hip structural abnormalities in hip pain. This study aimed to systematically evaluate the association of hip abnormalities on MRI, such as cartilage defects, bone marrow lesions (BMLs), osteophytes, paralabral cysts, effusion-synovitis, and subchondral cysts, with hip pain. We searched electronic databases from inception to February 2024, to identify publications that reported data on the association between MRI features in the hip joint and hip pain. The quality of the included studies was scored using the Newcastle-Ottawa Scale (NOS). The levels of evidence were evaluated according to the Cochrane Back Review Group Method Guidelines and classified into five levels: strong, moderate, limited, conflicting, and no evidence. A total of nine studies were included, comprising five cohort studies, three cross-sectional studies, and one case-control study. Moderate level of evidence suggested a positive association of the presence and change of BMLs with the severity and progress of hip pain, and evidence for the associations between other MRI features and hip pain were limited or even conflicting. Only a few studies with small to modest sample sizes evaluated the association between hip structural changes on MRI and hip pain. BMLs may contribute to the severity and progression of hip pain. Further studies are warranted to uncover the role of hip MRI abnormalities in hip pain. The protocol for the systematic review was registered with PROSPERO (https://www.crd.york.ac.uk/PROSPERO/, CRD42023401233).
Risks of exercise in older adults range from the over-stated (running causes knee osteoarthritis—it does not) to the under-appreciated (pickleball has a high risk of injury). Fortunately, the extensive benefits of exercise can be realized by mitigating risks among older adults with existing chronic conditions. While the risk-to-benefit ratio for exercise needs to be considered at the level of the individual, this joint statement from the American College of Sports Medicine and American Heart Association is highly relevant, “Physicians should not overestimate the risks of exercise because the benefits of habitual physical activity substantially outweigh the risks.”
Objectives
The purpose of this study was to describe injury patterns and healthcare utilisation of marathon runners.
Methods
This was a previously reported 16-week prospective observational study of runners training for the New York City Marathon. Runners completed a baseline survey including demographics, running experience and marathon goal. Injury surveys were collected every 4 weeks during training, as well as 1 week before and 1 week after the race. Injury details collected included anatomic location, diagnosis, onset, and treatment received.
Results
A total of 1049 runners were enrolled. Injuries were reported by 398 (38.4%) during training and 128 (14.1%) during the marathon. The overall prevalence of injury was 447/1049 (42.6%). Foot, knee and hip injuries were most common during training, whereas knee, thigh and foot injuries were most common during the race. The most frequent tissue type affected was the category of muscle, tendon/fascia and bursa. The prevalence of overuse injuries increased, while acute injuries remained constant throughout training. Hamstring injuries had the highest prevalence of diagnosis with 38/564 injuries (6.7%). Of the 447 runners who reported an injury, 224 (50.1%) received medical care. Physical therapy was the most common medical care received with 115/1037 (11.1%) runners during training and 44/907 (4.9%) postrace.
Conclusion
Runners training and participating in a marathon commonly experience injuries, especially of the foot and knee, which often are overuse soft tissue injuries. Half of the injured runners sought out medical care for their injury. Understanding the patterns of injuries affecting marathon runners could help guide future injury prevention efforts.
Background: The exercise is a widely promoted way to improve and maintain health, and osteoarthritis (OA) is a major health problem also. The study was conducted to examine the impact of different types of leisure-time physical activity on the OA of the knee.
Objective: The study was aimed to evaluate the association of recreational (habitual) physical activities with the osteoarthritis of the knee in the female.
Methods: The case-control study was carried out on 174 female selected purposively with the age range of 40 – 70 years and above, from September 2016 to August 2017.Among them 87 were the
cases with OA of the knee, and the same number of healthy females of the same age group were included as the control. Physical activity was assessed by self-reported regular exercise patterns. A structured interviewer-administered questionnaire was used to collect data.
Results: Age, educational status, occupational status and BMI were not statistically significant (p>0.05) between the two groups. High level of physical activities (walking, running or jogging 20 or more miles per week) were associated with osteoarthritis of the knee, while low level of physical activities (<10miles/per week) and moderate level of physical activities (10-20 miles/per week) had no significant association with the osteoarthritis of the knee.
Conclusion: Based on the findings, the study suggests not to continue a high level of physical activities rather than to continue with moderate and low level of physical activity in accordance to subject’s physical propensity, and endorse this note for the general health promotion.
Keywords: Osteoarthritis, Habitual physical exercise, Physical propensity, High level physical activity
Background: The exercise is a widely promoted way to improve and maintain health, and osteoarthritis (OA) is a major health problem also. The study was conducted to examine the impact of different types of leisure-time physical activity on the OA of the knee.
Objective: Evaluate the association of recreational (habitual) physical activities with the osteoarthritis of the knee in the female.
Methods: The case-control study was carried out on 174 female selected purposively with the age range of 40 – 70 years and above, from September 2016 to August 2017, among them 87 were the cases with OA of the knee, and the same number of healthy females of the same age group were included as the control. Physical activity was assessed by self-reported regular exercise patterns. A structured interviewer-administered questionnaire was used to collect data.
Results: Age, educational status, occupational status and BMI were not statistically significant (p >0.05) between the two groups. High level of physical activities (walking, running or jogging 20 or more miles per week) were associated with osteoarthritis of the knee, while low level of physical activities (<10 miles/per week) and moderate level of physical activities (10-20 miles/per week) had no significant association with the osteoarthritis of the knee.
Conclusion: To be concerned with OA of the knee, the study suggests not to continue a high level of physical activities rather than to continue with moderate and low level of physical activity in accordance to subject’s physical propensity, and endorse this note for the general health promotion.
Keywords: Osteoarthritis (OA), exercise, risk factor
Objectives
To evaluate the perceptions of the general public and healthcare practitioners (HCP) in Canada about the relationship between running and knee joint health, and to explore HCP`s usual recommendations to runners with knee osteoarthritis (KOA).
Methods
Non-runners and runners (with and without KOA) and HCP completed an online survey regarding the safety of running for knee joint health. HCP also provided information related to usual clinical recommendations. Proportions of agreement were compared between non-runners and runners.
Results
A total of 114 non-runners, 388 runners and 329 HCP completed the survey. Overall, running was perceived as detrimental for the knee joint by 13.1% of the general public, while 25.9% were uncertain. More uncertainty was reported regarding frequent (33.9%) and long-distance (43.6%) running. Statistical analyses revealed greater proportions of non-runners perceiving running negatively compared with runners. Overall, 48.4% believed that running in the presence of KOA would lead to disease progression, while 53.1% believed running would lead to premature arthroplasty. In HCP, 8.2%, 9.1% and 22.2% perceived that running in general, running frequently, or running long-distances are risk factors for KOA, respectively. 37.1% and 2.7% of HCP typically recommended patients with KOA to modify their running training or to quit running, respectively.
Conclusion
High rates of uncertainty among the general public and HCP in Canada outline the need for further studies about running and knee joint health. Filling knowledge gaps will help inform knowledge translation strategies to better orientate the general public and HCP about the safety of running for knee joint health.
Background
Synthesis of multiple randomized controlled trials (RCTs) in a systematic review can summarize the effects of individual outcomes and provide numerical answers about the effectiveness of interventions. Filtering of searches is time consuming, and no single method fulfills the principal requirements of speed with accuracy. Automation of systematic reviews is driven by a necessity to expedite the availability of current best evidence for policy and clinical decision-making.
We developed Rayyan (http://rayyan.qcri.org), a free web and mobile app, that helps expedite the initial screening of abstracts and titles using a process of semi-automation while incorporating a high level of usability. For the beta testing phase, we used two published Cochrane reviews in which included studies had been selected manually. Their searches, with 1030 records and 273 records, were uploaded to Rayyan. Different features of Rayyan were tested using these two reviews. We also conducted a survey of Rayyan’s users and collected feedback through a built-in feature.
Results
Pilot testing of Rayyan focused on usability, accuracy against manual methods, and the added value of the prediction feature. The “taster” review (273 records) allowed a quick overview of Rayyan for early comments on usability. The second review (1030 records) required several iterations to identify the previously identified 11 trials. The “suggestions” and “hints,” based on the “prediction model,” appeared as testing progressed beyond five included studies. Post rollout user experiences and a reflexive response by the developers enabled real-time modifications and improvements. The survey respondents reported 40% average time savings when using Rayyan compared to others tools, with 34% of the respondents reporting more than 50% time savings. In addition, around 75% of the respondents mentioned that screening and labeling studies as well as collaborating on reviews to be the two most important features of Rayyan.
As of November 2016, Rayyan users exceed 2000 from over 60 countries conducting hundreds of reviews totaling more than 1.6M citations. Feedback from users, obtained mostly through the app web site and a recent survey, has highlighted the ease in exploration of searches, the time saved, and simplicity in sharing and comparing include-exclude decisions. The strongest features of the app, identified and reported in user feedback, were its ability to help in screening and collaboration as well as the time savings it affords to users.
Conclusions
Rayyan is responsive and intuitive in use with significant potential to lighten the load of reviewers.
Osteoarthritis (OA) is a growing public health problem across the globe, affecting more than half of the over 65 population. In the past, OA was considered a wear and tear disease, leading to the loss of articular cartilage and joint disability. Nowadays, thanks to advancements in molecular biology, OA is believed to be a very complex multifactorial disease. OA is a degenerative disease characterized by “low-grade inflammation” in cartilage and synovium, resulting in the loss of joint structure and progressive deterioration of cartilage. Although the disease can be dependent on genetic and epigenetic factors, sex, ethnicity, and age (cellular senescence, apoptosis and lubricin), it is also associated with obesity and overweight, dietary factors, sedentary lifestyle and sport injuries. The aim of this review is to highlight how certain behaviors, habits and lifestyles may be involved in the onset and progression of OA and to summarize the principal risk factors involved in the development of this complicated joint disorder.
The DerSimonian and Laird approach (DL) is widely used for random effects meta-analysis, but this often results in inappropriate type I error rates. The method described by Hartung, Knapp, Sidik and Jonkman (HKSJ) is known to perform better when trials of similar size are combined. However evidence in realistic situations, where one trial might be much larger than the other trials, is lacking. We aimed to evaluate the relative performance of the DL and HKSJ methods when studies of different sizes are combined and to develop a simple method to convert DL results to HKSJ results.
We evaluated the performance of the HKSJ versus DL approach in simulated meta-analyses of 2-20 trials with varying sample sizes and between-study heterogeneity, and allowing trials to have various sizes, e.g. 25% of the trials being 10-times larger than the smaller trials. We also compared the number of "positive" (statistically significant at p < 0.05) findings using empirical data of recent meta-analyses with > =3 studies of interventions from the Cochrane Database of Systematic Reviews.
The simulations showed that the HKSJ method consistently resulted in more adequate error rates than the DL method. When the significance level was 5%, the HKSJ error rates at most doubled, whereas for DL they could be over 30%. DL, and, far less so, HKSJ had more inflated error rates when the combined studies had unequal sizes and between-study heterogeneity. The empirical data from 689 meta-analyses showed that 25.1% of the significant findings for the DL method were non-significant with the HKSJ method. DL results can be easily converted into HKSJ results.
Our simulations showed that the HKSJ method consistently results in more adequate error rates than the DL method, especially when the number of studies is small, and can easily be applied routinely in meta-analyses. Even with the HKSJ method, extra caution is needed when there are = <5 studies of very unequal sizes.
Objective: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Design: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30
The metafor package provides functions for conducting meta-analyses in R. The package includes functions for fitting the meta-analytic fixed- and random-effects models and allows for the inclusion of moderators variables (study-level covariates) in these models. Meta-regression analyses with continuous and categorical moderators can be conducted in this way. Functions for the Mantel-Haenszel and Peto's one-step method for meta-analyses of 2 x 2 table data are also available. Finally, the package provides various plot functions (for example, for forest, funnel, and radial plots) and functions for assessing the model fit, for obtaining case diagnostics, and for tests of publication bias.
The magnitude and duration of the benefit of running and other aerobic exercise on disability and mortality in elderly persons are not well understood. We sought to quantify the benefits of aerobic exercise, including running, on disability and mortality in elderly persons and to examine whether morbidity can be compressed into later years of life by regular exercise.
A 13-year prospective cohort study of 370 members of a runners' club for persons aged 50 and older and 249 control subjects initially aged 50 to 72 years (mean, 59 years), with annual ascertainment of the Health Assessment Questionnaire disability score, noting any deaths and their causes. Linear mixed models were used to compute postponement in disability, and survival analysis was conducted to determine the time to and causes of death.
Significantly (P<.001) lower disability levels in runners' club members vs controls and in ever runners vs never runners were sustained for at least 13 years. Reaching a Health Assessment Questionnaire disability level of 0.075 was postponed by 8.7 (95% confidence interval [CI], 5.5-13.7) years in runners' club members vs controls. Running club membership and participation in other aerobic exercise protected against mortality (rate ratio, 0.36 [95% CI, 0.20-0.65] and 0.88 [95% CI, 0.77-0.99], respectively), while male sex and smoking were detrimental (rate ratio, 2.4 [95% CI, 1.4-4.2] and 2.2 [95% CI, 1.1-4.6], respectively). Controls had a 3.3 times higher rate of death than runners' club members, with higher death rates in every disease category. Accelerated rates of disability and mortality were still not seen in the runners' club members; true compression of morbidity was not yet observable through an average age of 72 years.
Running and other aerobic exercise in elderly persons protect against disability and early mortality, and are associated with prolongation of a disability-free life.
We studied the long term impact of running and other aerobic exercise on musculoskeletal pain in a cohort of healthy aging male and female seniors who had been followed for 14 years. We conducted a prospective, longitudinal study in 866 Runners' Association members (n = 492) and community controls (n = 374). Subjects were also categorized as Ever-Runners (n = 565) and Never-Runners (n = 301) to include runners who had stopped running. Pain was the primary outcome measure and was assessed in annual surveys on a double-anchored visual analogue scale (0 to 100; 0 = no pain). Baseline differences between Runners' Association members and community controls and between Ever-Runners versus Never-Runners were compared using chi-square and t-tests. Statistical adjustments for age, body mass index (BMI), gender, health behaviors, history of arthritis and comorbid conditions were performed using generalized estimating equations. Runner's Association members were younger (62 versus 65 years, p < 0.05), had a lower BMI (22.9 versus 24.2, p < 0.05), and less arthritis (35% versus 41%, p > 0.05) than community controls. Runners' Association members averaged far more exercise minutes per week (314 versus 123, p < 0.05) and miles run per week (26 versus 2, p < 0.05) and tended to report more fractures (53% versus 47%, p > 0.05) than controls. Ever-Runners were younger (62 versus 66 years, p < 0.05), had lower BMI (23.0 versus 24.3, p < 0.05), and less arthritis (35% versus 43%, p < 0.05) than Never-Runners. Ever-Runners averaged more exercise minutes per week (291 versus 120, p < 0.05) and miles run per week (23 versus 1, p < 0.05) and reported a few more fractures (52% versus 48%, p > 0.05) than Never-Runners. Exercise was associated with significantly lower pain scores over time in the Runners' Association group after adjusting for gender, baseline BMI, and study attrition (p < 0.01). Similar differences were observed for Ever-Runners versus Never-Runners. Consistent exercise patterns over the long term in physically active seniors are associated with about 25% less musculoskeletal pain than reported by more sedentary controls, either by calendar year or by cumulative area-under-the-curve pain over average ages of 62 to 76 years.
Objective:
To investigate the consequences and prognostic factors of running-related knee injuries (RRKIs) among recreational runners.
Design:
Prospective cohort study.
Setting:
This study is part of a randomized-controlled trial (RCT) on running injury prevention among recreational runners. At baseline during registration for a running event (5-42 km), demographic and training variables were collected. Participants who reported a new RRKI during follow-up were sent a knee-specific questionnaire at 16 months (range 11.7-18.6) after baseline.
Participants:
One hundred thirty-eight runners who reported a new RRKI during the RCT on injury prevention responded to the knee-specific questionnaire.
Assessment of risk factors:
To determine the association between potential prognostic factors and time to recovery of an RRKI, a Cox regression analysis was performed.
Main outcome measures:
Time to recovery and prognostic factors of RRKIs.
Results:
At 16 months after registration, 71.0% of the participants reported full recovery, with a median time to recovery of 8.0 weeks. Most participants reported iliotibial band syndrome (23.2%) or osteoarthritis (OA)/degenerative meniscopathy (23.2%) as cause of their injury. Male sex was associated with a shorter time to recovery [hazard ratio (HR) 1.84; 95% confidence interval (CI), 1.14-2.97], while suffering knee OA was associated with a longer time to recovery (HR 0.17; 95% CI, 0.06-0.46).
Conclusions:
Nonrecovered participants adjusted running speed more often and had knee imaging more often than recovered participants. At follow-up, one-third of the participants were not recovered. This emphasizes the need for injury prevention programs for runners. More knowledge on the role of running in knee OA seems important, given the high number of participants with knee OA symptoms.
Objective
Meta-analysis is of fundamental importance to obtain an unbiased assessment of the available evidence. In general, the use of meta-analysis has been increasing over the last three decades with mental health as a major research topic. It is then essential to well understand its methodology and interpret its results. In this publication, we describe how to perform a meta-analysis with the freely available statistical software environment R, using a working example taken from the field of mental health.
Methods
R package meta is used to conduct standard meta-analysis. Sensitivity analyses for missing binary outcome data and potential selection bias are conducted with R package metasens. All essential R commands are provided and clearly described to conduct and report analyses.
Results
The working example considers a binary outcome: we show how to conduct a fixed effect and random effects meta-analysis and subgroup analysis, produce a forest and funnel plot and to test and adjust for funnel plot asymmetry. All these steps work similar for other outcome types.
Conclusions
R represents a powerful and flexible tool to conduct meta-analyses. This publication gives a brief glimpse into the topic and provides directions to more advanced meta-analysis methods available in R.
A systematic review and meta‐analysis is an important step in evidence synthesis. The current paradigm for meta‐analyses requires a presentation of the means under a random‐effects model; however, a mean with a confidence interval provides an incomplete summary of the underlying heterogeneity in meta‐analysis. Prediction intervals show the range of true effects in future studies and have been advocated to be regularly presented. Most commonly, prediction intervals are estimated assuming that the underlying heterogeneity follows a normal distribution, which is not necessarily appropriate. In this article, we provide a simple method with a ready‐to‐use spreadsheet file to estimate prediction intervals and predictive distributions non‐parametrically. Simulation studies show that this new method can provide approximately unbiased estimates compared with the conventional method. We also illustrate the advantage and real‐world significance of this approach with a meta‐analysis evaluating the protective effect of vaccination against tuberculosis. The nonparametric predictive distribution provides more information about the shape of the underlying distribution than does the conventional method.
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.
Population:
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.
Study Design
Systematic review and meta-analysis.
Background
Running is a healthy and popular activity worldwide, but data regarding its association with osteoarthritis (OA) are conflicting.
Objectives
To evaluate the association of hip and knee OA with running and to explore the influence of running intensity on this association.
Methods
PubMed, Embase, and Cochrane Library databases were used to identify studies investigating the occurrence of OA of the hip and/or knee among runners. A meta-analysis of studies comparing this occurrence between runners and controls (sedentary, nonrunning individuals) was conducted. Runners were regarded as “competitive” if they were reported as professional/elite athletes or participated in international competitions. Recreational runners were individuals running in a nonprofessional (amateur) context. The prevalence rate and odds ratio (with 95% confidence interval [CI]) for OA between runners (at competitive and recreational levels) and controls were calculated. Subgroup analyses were conducted for OA location (hip or knee), sex, and years of exposure to running (less or more than 15 years).
Results
Twenty-five studies (n = 125810 individuals) were included and 17 (n = 114829 individuals) were meta-analyzed. The overall prevalence of hip and knee OA was 13.3% (95% CI: 11.6%, 15.2%) in competitive runners, 3.5% (95% CI: 3.4%, 3.6%) in recreational runners, and 10.2% (95% CI: 9.9%, 10.6%) in controls. The odds ratio for hip and/or knee OA in competitive runners was higher than that in recreational runners (1.34; 95% CI: 0.97, 1.86 and 0.86; 95% CI: 0.69, 1.07, respectively; controls as reference group; for difference, P<.001). Exposure to running of less than 15 years was associated with a lower association with hip and/or knee OA compared with controls (OR = 0.6; 95% CI: 0.49, 0.73).
Conclusion
Recreational runners had a lower occurrence of OA compared with competitive runners and controls. These results indicated that a more sedentary lifestyle or long exposure to high-volume and/or high-intensity running are both associated with hip and/or knee OA. However, it was not possible to determine whether these associations were causative or confounded by other risk factors, such as previous injury.
Level of Evidence
Etiology/harm, level 2a. J Orthop Sports Phys Ther 2017;47(6):373–390. doi:10.2519/jospt.2017.7137
Runners do not have a greater prevalence of knee osteoarthritis (OA) than non-runners. The hypothesis that joint loads in running do not cause OA is forwarded. Two mechanisms are proposed: 1) cumulative load, which is surprisingly low in running, is more important for OA risk than peak load, and 2) running conditions cartilage to withstand the mechanical stresses of running.
Background:
Osteoarthritis (OA) is a chronic condition characterized by pain, impaired function, and reduced quality of life. A number of risk factors for knee OA have been identified, such as obesity, occupation, and injury. The association between knee OA and physical activity or particular sports such as running is less clear. Previous reviews, and the evidence that informs them, present contradictory or inconclusive findings.
Purpose:
This systematic review aimed to determine the association between running and the development of knee OA.
Study design:
Systematic review and meta-analysis.
Methods:
Four electronic databases were searched, along with citations in eligible articles and reviews and the contents of recent journal issues. Two reviewers independently screened the titles and abstracts using prespecified eligibility criteria. Full-text articles were also independently assessed for eligibility. Eligible studies were those in which running or running-related sports (eg, triathlon or orienteering) were assessed as a risk factor for the onset or progression of knee OA in adults. Relevant outcomes included (1) diagnosis of knee OA, (2) radiographic markers of knee OA, (3) knee joint surgery for OA, (4) knee pain, and (5) knee-associated disability. Risk of bias was judged by use of the Newcastle-Ottawa scale. A random-effects meta-analysis was performed with case-control studies investigating arthroplasty.
Results:
After de-duplication, the search returned 1322 records. Of these, 153 full-text articles were assessed; 25 were eligible, describing 15 studies: 11 cohort (6 retrospective) and 4 case-control studies. Findings of studies with a diagnostic OA outcome were mixed. Some radiographic differences were observed in runners, but only at baseline within some subgroups. Meta-analysis suggested a protective effect of running against surgery due to OA: pooled odds ratio 0.46 (95% CI, 0.30-0.71). The I(2) was 0% (95% CI, 0%-73%). Evidence relating to symptomatic outcomes was sparse and inconclusive.
Conclusion:
With this evidence, it is not possible to determine the role of running in knee OA. Moderate- to low-quality evidence suggests no association with OA diagnosis, a positive association with OA diagnosis, and a negative association with knee OA surgery. Conflicting results may reflect methodological heterogeneity. More evidence from well-designed, prospective studies is needed to clarify the contradictions.
The Medical Education Research Study Quality Instrument (MERSQI) and the Newcastle-Ottawa Scale-Education (NOS-E) were developed to appraise methodological quality in medical education research. The study objective was to evaluate the interrater reliability, normative scores, and between-instrument correlation for these two instruments.
In 2014, the authors searched PubMed and Google for articles using the MERSQI or NOS-E. They obtained or extracted data for interrater reliability-using the intraclass correlation coefficient (ICC)-and normative scores. They calculated between-scale correlation using Spearman rho.
Each instrument contains items concerning sampling, controlling for confounders, and integrity of outcomes. Interrater reliability for overall scores ranged from 0.68 to 0.95. Interrater reliability was "substantial" or better (ICC > 0.60) for nearly all domain-specific items on both instruments. Most instances of low interrater reliability were associated with restriction of range, and raw agreement was usually good. Across 26 studies evaluating published research, the median overall MERSQI score was 11.3 (range 8.9-15.1, of possible 18). Across six studies, the median overall NOS-E score was 3.22 (range 2.08-3.82, of possible 6). Overall MERSQI and NOS-E scores correlated reasonably well (rho 0.49-0.72).
The MERSQI and NOS-E are useful, reliable, complementary tools for appraising methodological quality of medical education research. Interpretation and use of their scores should focus on item-specific codes rather than overall scores. Normative scores should be used for relative rather than absolute judgments because different research questions require different study designs.
Objective:
Information regarding the relative risks of developing knee osteoarthritis (OA) as a result of sport participation is critical for shaping public health messages and for informing knee-OA prevention strategies. The purpose of this systematic review was to investigate the association between participation in specific sports and knee OA.
Data sources:
We completed a systematic literature search in September 2012 using 6 bibliographic databases (PubMed; Ovid MEDLINE; Journals@Ovid; American College of Physicians Journal Club; Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Review, Database of Abstracts of Reviews of Effects; and Ovid HealthStar), manual searches (4 journals), and reference lists (56 articles).
Study selection:
Studies were included if they met the following 4 criteria: (1) an aim was to investigate an association between sport participation and knee OA; (2) the outcome measure was radiographic knee OA, clinical knee OA, total knee replacement, self-reported diagnosis of knee OA, or placement on a waiting list for a total knee replacement; (3) the study design was case control or cohort; and (4) the study was written in English. Articles were excluded if the study population had an underlying condition other than knee OA.
Data extraction:
One investigator extracted data (eg, group descriptions, knee OA prevalence, source of nonexposed controls).
Data synthesis:
The overall knee-OA prevalence in sport participants (n = 3759) was 7.7%, compared with 7.3% among nonexposed controls (referent group n = 4730, odds ratio [OR] = 1.1). Specific sports with a significantly higher prevalence of knee OA were soccer (OR = 3.5), elite-level long-distance running (OR = 3.3), competitive weight lifting (OR = 6.9), and wrestling (OR = 3.8). Elite-sport (soccer or orienteering) and nonelite-sport (soccer or American football) participants without a history of knee injury had a greater prevalence of knee OA than nonexposed participants.
Conclusions:
Participants in soccer (elite and nonelite), elite-level long-distance running, competitive weight lifting, and wrestling had an increased prevalence of knee OA and should be targeted for risk-reduction strategies.
Background:
Acute effects of physical exercise on the deformational behaviour of articular cartilage and changes in cartilage oligomeric matrix protein (COMP) are definite. However, conclusive positive effects of fitness exercise on functional adaptation of articular cartilage have not been proved.
Aim:
Therefore, in this parallel-group randomised controlled trial, we tested the hypothesis that adequate amount of physical exercise with enough impact would be able to stimulate the functional behaviour of articular cartilage.
Methods:
We evaluated 44 healthy males for their physical-fitness levels and their blood samples were obtained before, immediately after and 0.5h after a 30-min walking exercise. Thereafter, participants were assigned to the running, the cycling, the swimming and the control groups. At the end of 12weeks of intervention, the same measurement procedures were applied. Mixed repeated-measures analysis of variance (ANOVA) design was used for statistics. (
Level of evidence:
2).
Results:
Pre-test measurements showed that 30min of walking significantly increased serum-COMP levels in all groups. The post-tests revealed that the COMP level of all groups, except running, showed an increase after a 30-min walking activity.
Conclusion:
Overall, it was concluded that, 12weeks of regular, weight-bearing, high-impact physical exercise (i.e., running) decreases the deformational effect of walking activity. This finding is an evidence of functional adaptation of articular cartilage to specific environmental requirements.
Objective. To estimate the risk of osteoarthritis (OA) of the hip and knee due to long-term weight-bearing sports activity in ex–elite athletes and the general population.
Methods. A retrospective cohort study was conducted of 81 female ex–elite athletes (67 middle- and long-distance runners, and 14 tennis players), currently ages 40–65, recruited from original playing records, and 977 age-matched female controls, taken from the age–sex register of the offices of a group general practice in Chingford, Northeast London, England. The definition of OA included radiologic changes (joint space narrowing and osteophytosis) in the hip joints, patellofemoral (PF) joints, and tibiofemoral (TF) joints.
Results. Compared with controls of similar age, the ex-athletes had greater rates of radiologic OA at all sites. This association increased further after adjustment for height and weight differences, and was strongest for the presence of osteophytes at the TF joints (odds ratio [OR] 3.57, 95% confidence interval [95% CI] 1.89–6.71), at the PF joints (OR 3.50, 95% CI 1.80–6.81), narrowing at the PF joints (OR 2.97, 95% CI 1.15–7.67), femoral osteophytes (OR 2.52, 95% CI 1.01–6.26), and hip joint narrowing (OR 1.60, 95% CI 0.73–3.48), and was weakest for narrowing at the TF joints (OR 1.17, 95% CI 0.71–1.94). No clear risk factors were seen within the ex-athlete groups, although the tennis players tended to have more osteophytes at the TF joints and hip, but the runners had more PF joint disease. Within the control group, a small subgroup of 22 women who reported long-term vigorous weight-bearing exercise had risks of OA similar to those of the ex-athletes. Ex-athletes had similar rates of symptom reporting but higher pain thresholds than controls, as measured by calibrated dolorimeter.
Conclusion. Weight-bearing sports activity in women is associated with a 2–3-fold increased risk of radiologic OA (particularly the presence of osteophytes) of the knees and hips. The risk was similar in ex–elite athletes and in a subgroup from the general population who reported long-term sports activity, suggesting that duration rather than frequency of training is important.
To evaluate lower-limb explosive strength with respect to lifetime athletic activity, we measured vertical jumping height
on a contact mat in former male runners (n = 28), soccer players (n = 31), weightlifters (n = 29) and shooters (n = 29) (age range 45–68 years). There were no statistically significant age-adjusted sport-group differences in jumping height,
but differences by sport were evident among the subgroup of athletes without hip or knee osteoarthritis (n = 65) (P < 0.05). Thus, sports that increased jumping height also predisposed to lower-limb osteoarthritis. After adjustment for age
and sport, the subjects without osteoarthritis jumped higher than those with osteoarthritis (n = 33) (P < 0.01). In a multiple linear regression analysis, age, reported hip and knee disability, and knee pain reduced jumping height.
Hours spent in team-training during the past 12 months and the hours spent during their lifetime in power training were associated
with improved vertical jumping height and together explained 41% of the difference among the subjects. The ability to jump
even among athletes with hip or knee osteoarthritis would suggest that former elite athletes possess advanced lower limb muscle
function.
Results of meta-analyses typically conclude that future large studies may be mandated. However, the predictive ability of these estimates is deficient. We explored meta-analytic prediction intervals as means for providing a clear and appropriate future treatment summary reflecting current estimates.
A meta-epidemiological study of binary outcome critical care meta-analyses published between 2002 and 2010. Computation of 95% DerSimonian-Laird and Bayesian random-effects meta-analytic confidence intervals (CI) and 95% credible intervals (CrI), respectively, and frequentist (PI) and Bayesian (PrI) prediction intervals for odds ratio (OR) and risk ratio (RR) were undertaken. Bayesian calculations included the probability that the OR and RR point estimates ≥1.
Seventy-two meta-analyses from 70 articles were identified, containing between three and 80 studies each, with median nine studies. For both frequentist and Bayesian settings, 49-69% of the meta-analyses excluded the null. All significant CrI had high probabilities of efficacy/harm. The number of PI vs. PrI excluding 1 was 25% vs. 3% (OR), 26% vs. 3% (RR) of the total meta-analyses. Unsurprisingly, PI/PrI width was greater than CI/CrI width and increased with increasing heterogeneity and combination of fewer studies.
Robust meta-analytic conclusions and determination of studies warranting new large trials may be more appropriately signaled by consideration of initial interval estimates with prediction intervals. Substantial heterogeneity results in exceedingly wide PIs. More caution should be exercised regarding the conclusions of a meta-analysis.
To longitudinally estimate the change in glycosaminoglycan content of knee cartilage in asymptomatic untrained female novice runners participating in a Start To Run program (STR) compared to sedentary controls.
Nine females enrolling in a 10-week STR and 10 sedentary controls participated voluntarily. Prior to and after the 10-week period, both groups were subjected to dGEMRIC imaging. dGEMRIC indices of knee cartilage were determined at baseline and for the change after the 10-week period in both groups. Based on a self-reported weekly log, physical activity change during the study was depicted as decreased, unchanged or increased. The Mann-Whitney U and Kruskal-Wallis tests were applied to test the hypotheses that dGEMRIC changes occurred between groups and according to physical activity changes respectively.
No significant differences were established between groups for dGEMRIC indices at baseline (P=0.541). A significant positive change of the median dGEMRIC index in the runners group was demonstrated when compared to the controls [+11.66ms (95% CI: -25.29, 44.43) vs -9.56ms (95% CI: -29.55, 5.83), P=0.006]. The change in dGEMRIC index differed significantly according to physical activity change (P=0.014), showing an increase in dGEMRIC index with increasing physical activity.
Since cartilage appears to positively respond to moderate running when compared to a sedentary lifestyle, this running scheme might be considered a valuable tool in osteoarthritis prevention strategies. Caution is warranted when applying these results to a wider population and to longer training periods.
Studies of the relation between joint function and mechanical stress have led to a revival of the old concept that primary osteoarthritis is actually a wearing out of joints. Recent experimental evidence suggests that joints can wear out by repetitive impulsive loading, rather than by rubbing. This new mechanistic approach is compatible with the pathology of, and clinical experience with, the disease.
Exercise remains an extremely popular leisure time activity in many countries throughout the western world. It is widely promoted in the lay press as having salutory benefits for weight control, disease management advantages for cardiovascular disease and diabetes, in addition to improving psychological well-being amongst an array of other benefits. In contrast, however, the lay press and community perception is also that exercise is potentially deleterious to one's joints. The purpose of this review is to consider what osteoarthritis (OA) is and provide an overview of the epidemiology of OA focusing on validated risk factors for its development. In particular the role of both exercise and occupational activity in OA will be described as well as the role of exercise to the joints' tissues (particularly cartilage) and the role of exercise in disease management. Despite the common misconception that exercise is deleterious to one's joints, in the absence of joint injury there is no evidence to support this notion. Rather it would appear that exercise has positive salutory benefits for joint tissues in addition to its other health benefits.
Recreational exercise programs, particularly running, remain popular for a variety of reasons. It has been estimated that as many as 20 to 30 million Americans exercise, and that this includes perhaps 5 to 15 million runners/joggers. Until recently, scant information was available regarding long-term effects, if any, of exercise on the musculoskeletal system. We, and others, therefore studied and reported our observations on the possible association of the development of lower extremity osteoarthritis (OA) in runners. This eight-year, follow-up study of our original 18 nonrunners and 17 runners obtained information on 16 runners (12 of whom were re-examined) and 13 nonrunners (10 of whom were re-examined) in 1992. One runner was deceased (cancer), 14/15 were exercising, 11/15 were running, and 3/15 were engaged in other recreational exercises. In 1992, as in 1984, pain, swelling, and range of motion of hips, knees, ankles, and feet were comparable for runners and nonrunners, and radiographic examinations (for osteophytes, cartilage thickness, and grade of OA) of hips, knees, ankles, and feet were without notable differences between groups. Thus, we did not find an increased prevalence of OA among our runners, now in their seventh decade. These observations support the suggestion that running need not be associated with predisposition to OA of the lower extremities.
Articular cartilage is avascular. Nutrients are transported to the cells mainly by diffusion from the synovial fluid. Nutrient transport is also sometimes thought to be assisted by movement of fluid in and out of cartilage in response to cyclic loading of the tissue ('pumping'). The influence of pumping on transport of solutes through cartilage was measured by subjecting plugs of human femoral head cartilage immersed in medium containing radioactive solutes to a simulated walking cycle of 2.8 MPa at 1 Hz. The rate of absorption or desorption of tracers from the cycled plugs was compared with that of unloaded control plugs. For small solutes (urea, NaI) fluid transport did not affect the rate of solute transport significantly. Most major nutrients, such as glucose and oxygen, are small solutes and thus nutrition should not be affected by pumping. The rate of desorption of a large solute (serum albumin), however, was increased by 30-100% in plugs subjected to cyclic loading.
In order to evaluate the effect of long-term, long distance running on the incidence of degenerative joint disease in the lower extremities, we examined the hips, knees, and ankles of 30 long distance runners who had been serious competitive runners in the early 1950s (at the age of 20 to 30 years). Of three runners who were no longer active, one had stopped running in the late 1970s because of osteoarthrosis of both the lower and upper extremity joints. The remaining 27 runners (90%) were still active, having run 20 to 40 km/week (12 to 24 miles/week) for a median of 40 years. Subjective, objective, and roentgenographic data were compared with the data for 27 nonrunning controls matched as to age, weight, height, and occupation. No differences in joint alignment, range of motion, or complaints of pain were found between runners and nonrunners. Roentgenographic examinations for cartilage thickness, grade of degeneration, and osteophytosis were also without significant differences between the two groups. Thus, our observations suggest that a lifetime of long distance running at mileage levels comparable to those of recreational runners today is not associated with premature osteoarthrosis in the joints of the lower extremities.
Concern exists that certain types of exercise, particularly vigorous activity, may increase physical disability among older individuals. We investigated the prevalence of, and risk factors for, physical disability in active older persons (runners), and examined factors influencing the progression of physical disability with age.
Physical disability, measured using the Health Assessment Questionnaire Disability Index, was assessed prospectively in 454 runners, age 50 or greater, over five to seven years by annual mailed questionnaires. Baseline sociodemographic, clinical, and life-style characteristics associated with the presence of any disability over the course of the study were determined and contrasted with those in 292 older non-runners who had been similarly followed.
Two hundred twenty-two runners (49%) reported some physical disability during the study. The presence of arthritis symptoms at baseline was the most important risk factor for physical disability; older age, greater body mass index, strenuous work-related physical activity, and the use of more medications were also associated with a greater likelihood of physical disability. Among the non-runners, 224 (77%) reported some physical disability, and the presence of arthritis symptoms was also the most important risk factor for physical disability in this group. Age-related changes in physical disability differed between those with and without arthritis symptoms in both the runner and non-runner groups.
The presence of arthritis symptoms was an important risk factor for physical disability among both older runners and non-runners, and also identified subgroups of individuals with different progressions of disability with age.
To determine, by longitudinal study, whether regular vigorous running activity is associated with accelerated, unchanged, or postponed development of disability with increasing age.
8-year prospective, longitudinal study with yearly assessments.
451 members of a runners' club and 330 community controls who were initially 50 to 72 years old (also characterized as "ever-runners" [n = 534] and "never-runners" [n = 247], respectively).
The dependent variable was disability as assessed by the Health Assessment Questionnaire and separately validated in these participant cohorts. Covariates included age, sex, body mass index, comorbid conditions, education level, smoking history, alcohol intake, mean blood pressure, initial disability level, family history of arthritis, and radiologic evidence of osteoarthritis of the knee in a subsample.
Initially, the runners were leaner, reported joint symptoms less frequently, took fewer medications, had fewer medical problems, and had fewer instances of and less severe disability, suggesting either that the average previous 12 years of running had improved health or that self-selection bias was present. After 8 years of longitudinal study, the differences in initial disability levels (0.026 compared with 0.079; P < 0.001) had steadily increased to 0.071 for runners compared with 0.242 for controls (P < 0.001). The difference was consistent for men and women. The rate of development of disability was several times lower in the runners' club members than in community controls; this difference persisted after adjusting for age, sex, body mass, baseline disability, smoking history, history of arthritis, or other comorbid conditions (slopes of progression of disability for the years 1984 to 1992, after adjusting for covariates: men in the runners' club, 0.004 [SE, 0.002]; community controls, 0.012 [SE, 0.002]; women in the runners' club, 0.009 [SE, 0.005]; community controls, 0.027 [SE, 0.004]; P < 0.002 for both sets of comparisons). In addition to differences in disability, there were significant differences in mortality between the runners' club members (1.49%) and community controls (7.09%) (P < 0.001). These differences remained significant after adjusting for age, sex, body mass, comorbid conditions, education level, smoking history, alcohol intake, and mean blood pressure (P < 0.002, conditional risk ratio for community controls compared with the runners, 4.27; 95% CI, 1.78 to 10.26).
Older persons who engage in vigorous running and other aerobic activities have lower mortality and slower development of disability than do members of the general population. This association is probably related to increased aerobic activity, strength, fitness, and increased organ reserve rather than to an effect of postponed osteoarthritis development.
To determine, by longitudinal study, whether long-distance running, maintained for many years, is associated with increased musculoskeletal pain with age.
A 6-year prospective longitudinal study of 410 runners' club members and 289 community controls, age 53-75 years at study initiation, was conducted. Subjects were also categorized as ever-runners (n = 488) and never-runners (n = 211). The primary dependent variable was pain score as indicated on a horizontal double-anchored analog scale; data for this variable were available beginning in 1987. Statistical adjustment for age, education level, smoking, alcohol consumption, history of arthritis, and presence of other major medical conditions was done by analysis of covariance. Further analyses of previously reported associations of regular vigorous physical activity with decreased disability and mortality after 9 years were performed.
The degree of musculoskeletal pain was slightly lower in the exercise group compared with controls, and the difference was statistically significant for women but not for men. Average adjusted pain scores for men were 18.3 (SEM 0.8) in runners' club members, 20.2 (1.2) in controls, 18.6 (0.8) in ever-runners, and 20.3 (1.6) in never-runners. For women, these scores were 17.5 (1.8) in runners' club members versus 22.8 (1.4) in controls (P < 0.05), and 17.2 in ever runners versus 23.7 (1.5) in never-runners (P < 0.002). Disability had continued to develop in runners' club members at a rate only one-third that in the controls after 9 years of observation. Mortality over 9 years consisted of 51 deaths, of which 41 were in the control group and only 10 were among runners' club members.
Vigorous running activity over many years is not associated with an increase in musculoskeletal pain with age, and there may be a moderate decrease in pain, particularly in women. Vigorous physical activity is associated with greatly decreased levels of disability and with decreased mortality rates.
This prospective study evaluated regular physical activity and self-reported physician-diagnosed osteoarthritis of the knee and/or hip joints among 16,961 people, ages 20-87, examined at the Cooper Clinic between 1970 and 1995. Among those aged 50 years and older, osteoarthritis incidence was higher among women (7.0 per 1000 person-years) than among men (4.9 per 1000 person-years, P = 0.001), while among those under 50 years of age, osteoarthritis incidence was similar between men (2.6) and women (2.7). High levels of physical activity (running 20 or more miles per week) were associated with osteoarthritis among men under age 50 after controlling for body mass index, smoking, and use of alcohol or caffeine (hazard ratio = 2.4, 95% CI: 1.5, 3.9), while no relationship was suggested among women or older men. These findings support the conclusion that high levels of physical activity may be a risk factor for symptomatic osteoarthritis among men under age 50.
To determine the relationship between previous lower-limb loading and current self-reported hip and knee disability, we sent a questionnaire to 1321 former elite male athletes who had represented Finland between 1920 and 1965 in international competitions and to 814 control subjects who had been classified as healthy at the age of 20. After adjustment for age, body mass index, and occupational group, the odds ratios of hip disability in the athletes compared with control subjects were 0.35 in endurance athletes (95% confidence interval, 0.14 to 0.85, P = 0.02), 0.56 in team sport athletes (0.28 to 1.10, P = 0.09), 0.30 in track and field athletes (0.12 to 0.73, P < 0.01), 0.84 in power sport athletes (0.51 to 1.39, P = 0.49), 0.30 in shooters (0.07 to 1.32, P = 0.11), and 0.54 (0.36 to 0.82, P < 0.01) in all athletes combined. Compared with control subjects, only team sport athletes had a higher risk of knee disability (odds ratio, 1.76; 95% confidence interval, 1.03 to 3.02; P = 0.04). Even though athletes have been reported to be at an increased risk for lower-limb osteoarthritis, our data show that former elite male endurance and track and field athletes and all athletes combined reported less hip disability than the control subjects. The effect of vigorous athletic activity on the function of knee joints is more controversial, because sports that involve a high risk of knee injury are likely to lead to pain, disability, and osteoarthritis.
The relationship between physical activity (PA) and the development of hip/knee osteoarthritis (OA) has not been clearly defined. The purpose of this study was to develop a method to quantify PA-related joint stress and to assess its influence on the risk of hip/knee OA.
Participants in a large longitudinal study, without knee/hip OA (n = 5284), were asked about their PA participation in 1986. PA-related joint stress was calculated using information on the frequency, intensity, and duration of individual types of PA, and incorporated a quantification of joint stress. Self-reported, physician-diagnosed hip/knee OA was ascertained by survey in 1990, 1995, and 1999 (average length of follow-up: 12.8 years).
The joint stress PA score was not associated with an increased risk of hip/knee OA. Also, among walkers and runners there was no association between the frequency, pace, or weekly training mileage and hip/knee OA. Older age, previous joint injury and surgery, and higher body mass index were confirmed as independent risk factors for hip/knee OA.
Participation in PA as an adult does not increase the risk of hip/knee OA and there does not seem to be a threshold of increasing risk with increased training among walkers and runners.
To describe the association between early radiographic osteoarthritis of the knee (ROA), knee cartilage volume and tibial bone surface area.
Cross-sectional convenience sample of 372 male and female subjects (mean age 45 years, range 26-61). Articular cartilage volume, bone area and volume were determined at the patella, medial tibial and lateral tibial compartments by processing images acquired in the sagittal plane using T1-weighted fat saturation MRI. ROA was assessed with a standing semiflexed radiograph and the OARSI atlas for joint space narrowing and osteophytosis. Both radiographs and MRIs were performed in the right knee and read by different observers.
ROA (predominantly grade 1) was present in 17% of subjects of which medial joint space narrowing was most common (14%) followed by medial osteophytes (6%). Grade one medial joint space narrowing was associated with substantial reductions in cartilage volume at both the medial and lateral tibial and patellar sites within the knee (adjusted mean difference 11-13%, all P<0.001) while grade one osteophytosis was associated with substantial increases in both lateral and medial tibial joint surface area (adjusted mean difference 10-16%, all P<0.001). In contrast, osteophytosis was not associated with a significant change in cartilage volume and joint space narrowing was not associated with a significant change in tibial bone area (all P>0.05).
Early medial compartment ROA is associated with substantial reductions in cartilage volume and increases in bone area. These large changes, when combined with similar measurement error for MRI and radiographs, suggest that MRI may be superior at detecting and hence understanding early osteoarthritis of the knee in humans.
Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a new imaging technique to estimate joint cartilage glycosaminoglycan content by T1-relaxation time measurements after penetration of the hydrophilic contrast agent Gd-DTPA(2-). This study compares dGEMRIC in age-matched healthy volunteers with different levels of physical activity: Group 1 (n = 12): nonexercising individuals; Group 2 (n = 16): individuals with physical exercise averaging twice weekly; Group 3 (n = 9): male elite runners. dGEMRIC was performed 2 hr after an intravenous injection of Gd-DTPA(2-) at 0.3 mmol/kg body weight. T1 differed significantly between the three different levels of physical exercise. T1 values (mean of medial and lateral femoral cartilage) for Groups 1, 2, and 3 were: 382 +/- 33, 424 +/- 22 and 476 +/- 36, respectively (ms, mean +/- SD) (P = 0.0004, 1 vs. 2 and 0.0002, 2 vs. 3). Irrespective of the exercise level, T1 was longer in lateral compared to medial femoral cartilage (P = 0.00005; n = 37). In conclusion, this cross-sectional study indicates that human knee cartilage adapts to exercise by increasing the glycosaminoglycan content. Furthermore, results suggest a compartmental difference within the knee with a higher glycosaminoglycan content in lateral compared to medial femoral cartilage. A higher proportion of extracellular water, i.e., larger distribution volume, may to some extent explain the high T1 in the elite runners.
Osteoarthritis is a progressive joint disease characterized by an imbalance of articular cartilage biosynthesis and degradation attributed to both inflammatory and biomechanical factors. Whereas moderate mechanical loading appears necessary for maintaining healthy cartilage, abnormal joint loading increases the risk of osteoarthritis. Obesity-induced osteoarthritis and the benefits of physical activity may be mediated by systemic levels of proinflammatory mediators as well as local biomechanical factors in the joint.
Prior studies of the relationship of physical activity to osteoarthritis (OA) of the knee have shown mixed results. The objective of this study was to determine if differences in the progression of knee OA in middle- to older-aged runners exist when compared with healthy nonrunners over nearly 2 decades of serial radiographic observation.
Forty-five long-distance runners and 53 controls with a mean age of 58 (range 50-72) years in 1984 were studied through 2002 with serial knee radiographs. Radiographic scores were two-reader averages for Total Knee Score (TKS) by modified Kellgren & Lawrence methods. TKS progression and the number of knees with severe OA were compared between runners and controls. Multivariate regression analyses were performed to assess the relationship between runner versus control status and radiographic outcomes using age, gender, BMI, education, and initial radiographic and disability scores among covariates.
Most subjects showed little initial radiographic OA (6.7% of runners and 0 controls); however, by the end of the study runners did not have more prevalent OA (20 vs 32%, p =0.25) nor more cases of severe OA (2.2% vs 9.4%, p=0.21) than did controls. Regression models found higher initial BMI, initial radiographic damage, and greater time from initial radiograph to be associated with worse radiographic OA at the final assessment; no significant associations were seen with gender, education, previous knee injury, or mean exercise time.
Long-distance running among healthy older individuals was not associated with accelerated radiographic OA. These data raise the possibility that severe OA may not be more common among runners.
dmetar: Companion R package for the guide 'doing meta-analysis in R
- M C P Harrer
- T Furukawa
- D Ebert
Harrer, M. C. P., Furukawa, T., & Ebert, D. (2019). dmetar: Companion R package for the
guide 'doing meta-analysis in R.