Recommendations for the delivery of therapeutic exercise for people with knee and/or hip osteoarthritis. An international consensus study from the OARSI Rehabilitation Discussion Group.

OBJECTIVE: To develop evidence-informed recommendations to support the delivery of best practice therapeutic exercise for people with knee and/or hip osteoarthritis (OA). DESIGN: A multi-stage, evidence-informed, international multi-disciplinary consensus process that included: 1) a narrative literature review to synthesise existing evidence; 2) generation of evidence-informed proposition statements about delivery of exercise for people with knee and/or hip OA by an international multi-disciplinary expert panel, with statements refined and analysed thematically; 3) an e-Delphi survey with the expert panel to gain consensus on the most important statements; 4) a final round of statement refinement and thematic analysis to group remaining statements into domains. RESULTS: The expert panel included 318 members (academics, health care professionals and exercise providers, patient representatives) from 43 countries. Final recommendations comprised 54 specific proposition statements across 11 broad domains: 1) use an evidence-based approach; 2) consider exercise in the context of living with OA and pain; 3) undertake a comprehensive baseline assessment with follow-up; 4) set goals; 5) consider the type of exercise; 6) consider the dose of exercise; 7) modify and progress exercise; 8) individualise exercise; 9) optimise the delivery of exercise; 10) focus on exercise adherence; and 11) provide education about OA and the role of exercise. CONCLUSION: The breadth of issues identified as important by the international diverse expert panel highlights that delivering therapeutic exercise for OA is multi-dimensional and complex.

Osteoarthritis in year 2021: biochemical markers.

OBJECTIVE: To summarize recent scientific advances in protein-derived soluble biomarkers of osteoarthritis. DESIGN: A systematic search on the PubMed electronic database of clinical studies on protein-derived soluble biochemical markers of osteoarthritis in humans that were published between January 1st 2020 and March 31th 2021. The studies were selected on the basis of objective criteria and summarized in a table. Then they were described in a narrative review. RESULTS: Out of 1971 publications, 48 fulfilled all selection criteria and 16 were selected by the author for the narrative review. The papers were classified according their clinical significance as defined in the BIPEDS classification. Two papers investigated the "burden of disease", two were dedicated to "investigative biomarkers", four papers question the "prognosis", three the "efficacy of treatment" and five the "diagnosis and phenotyping" value of protein-derived biomarkers. CONCLUSIONS: Currently, biomarkers research is focused on their use as tools to identify molecular endotypes and clinical phenotypes and to facilitate patient screening and monitoring in clinical trials. This approach should allow a more targeted management of patients suffering from osteoarthritis.

Bio-optimized Curcuma longa extract is efficient on knee osteoarthritis pain: a double-blind multicenter randomized placebo controlled three-arm study.

OBJECTIVES: Comparison of two doses of bio-optimized Curcuma longa extract (BCL) in the management of symptomatic knee osteoarthritis (OA). METHODS: A prospective, randomized, 3-month, double-blind, multicenter, three-group, placebo-controlled trial assessing Patient Global Assessment of Disease Activity (PGADA) and serum sColl2-1, a biomarker of cartilage degradation, as co-primary endpoints. Pain on visual analog scale (VAS), Knee injury and Osteoarthritis Outcome Score (KOOS), and paracetamol/non-steroidal anti-inflammatory drug (NSAID) consumption were used as secondary endpoints. RESULTS: One hundred fifty patients with knee OA were followed for 90 days. Low and high doses of BCL showed a greater decrease of PGADA than placebo. Analysis of sColl2-1 showed in the placebo and BCL low-dose groups, but not in the BCL high-dose group, a transient but non-significant increase of sColl2-1 between T0 and T1. Thereafter, in all groups, sColl2-1 decreased between T1 and T3 (all p < 0.01), but no difference between the groups was found. Pain reduction at day 90 in the low- and high-dose BCL groups (- 29.5 mm and - 36.5 mm) was higher than that in the placebo (- 8 mm; p = 0.018). The global KOOS significantly decreased overtime, but changes were comparable across treatment arms. The ratio of patients with adverse events (AE) related to the product was similar in the placebo and treatment groups, but the number of AE linked to the product was higher in the high-dose BCL group compared to the placebo (p = 0.012). CONCLUSIONS: BCL appeared safe and well-tolerated with no evidence of severe adverse effects. Efficacy analysis suggested positive trends for measurements of PGADA and serum levels of an OA biomarker and showed a rapid and significant decrease of pain in knee OA (Trial registration: ISRCTN, ISRCTN12345678. Registered 21 September 2016-retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02909621?term=osteoarthritis+curcumin&rank=5-Evaluation of FLEXOFYTOL® Versus PLACEBO (COPRA) NCT02909621).

Type II collagen peptide Coll2-1 is an actor of synovitis.

OBJECTIVE: We evaluated the ability of Coll2-1, a type II collagen peptide, to activate pro-inflammatory pathways in synovial cells and to induce arthritis in Lewis rats. METHOD: Human synoviocytes and chondrocytes from knee OA patients were cultured for 24 h with/without Coll2-1 and/or purified immunoglobulin G (AS0619) binding specifically this peptide, and/or CLI-095, a TLR-4 signaling inhibitor and/or apocynin and diphenyleneiodonium, Reactive oxygen species (ROS) production inhibitors. The Interleukin (IL)-8 and Vascular Endothelium Growth Factor (VEGF) expression, the IL-8 production, the IκB-α and p65 phosphorylation and ROS were evaluated. Coll2-1 peptide, bovine type II collagen (CIA), streptococcal cell wall (SCW) or saline solution were injected into Lewis rats. The Coll2-1 peptide was injected subcutaneously (SC; 20-200µg/100µl/animal) or intra-articularly (IA; 0.5-5µg/50µl/animal) and compared to CIA injected in SC (200µg/100µl/animal) and SCW in IA (5µg/50µl/animal). The animals were injected on day 0 and monitored for 28 days. Histological lesions assessment was performed using an arthritis score. RESULTS: Coll2-1 peptide significantly increased IL-8 gene expression and production by synoviocytes. AS0619 and CLI-095 significantly decreased IL-8 expression. Coll2-1 induced p65 and IκBα phosphorylation and oxidative stress inhibitors decreased it. In human chondrocytes culture, Coll2-1 significantly increased MMP-3 and VEGF gene expression. In Lewis rats, CIA, SCW or Coll2-1 injection triggered arthritis. Like CIA or SCW, Coll2-1 induced synovitis, loss of cartilage proteoglycans, cartilage structure lesion and subchondral bone remodeling. CONCLUSIONS: Coll2-1 activates synoviocytes to produce IL-8 and induces arthritis in rat. These findings suggest that neutralizing Coll2-1 could be a therapeutic approach of arthritis.

A machine learning approach for the identification of new biomarkers for knee osteoarthritis development in overweight and obese women.

OBJECTIVE: Knee osteoarthritis (OA) is among the higher contributors to global disability. Despite its high prevalence, currently, there is no cure for this disease. Furthermore, the available diagnostic approaches have large precision errors and low sensitivity. Therefore, there is a need for new biomarkers to correctly identify early knee OA. METHOD: We have created an analytics pipeline based on machine learning to identify small models (having few variables) that predict the 30-months incidence of knee OA (using multiple clinical and structural OA outcome measures) in overweight middle-aged women without knee OA at baseline. The data included clinical variables, food and pain questionnaires, biochemical markers (BM) and imaging-based information. RESULTS: All the models showed high performance (AUC > 0.7) while using only a few variables. We identified both the importance of each variable within the models as well its direction. Finally, we compared the performance of two models with the state-of-the-art approaches available in the literature. CONCLUSIONS: We showed the potential of applying machine learning to generate predictive models for the knee OA incidence. Imaging-based information were found particularly important in the proposed models. Furthermore, our analysis confirmed the relevance of known BM for knee OA. Overall, we propose five highly predictive small models that can be possibly adopted for an early prediction of knee OA.

Relationship between weight loss in obese knee osteoarthritis patients and serum biomarkers of cartilage breakdown: secondary analyses of a randomised trial.

OBJECTIVE: To explore effects of weight loss and maintenance on serum cartilage biomarkers denaturation neoepitope for Collagen2 (Coll2-1) and Fibulin3 fragment (Fib3-2), as well as correlations between Coll2-1 and Fib3-2 and symptomatic improvement, in a knee osteoarthritis (KOA) population. DESIGN: 192 obese KOA patients followed a 16 week weight loss intervention and 52 weeks weight maintenance (ClinicalTrials.gov identifier: NCT00655941). Assessments were at 0, 8, 16 and 68 weeks. Serum Coll2-1 and Fib3-2 were determined with ELISA, and symptoms by the Knee Osteoarthritis Outcome Score (KOOS) questionnaire. Changes from week 0 and association between changes from baseline in body weight and Coll2-1, Fib3-2, and the 5 KOOS domains were assessed at all time points. RESULTS: Coll2-1 changes from baseline showed a decrease at week 8 (P = 0.0002), no change at week 16 (P = 0.49), and an increase at week 68 (P = 0.036). Fib3-2 showed an increase from baseline at week 8 (P = 0.0015) and 16 (P < 0.0001), but none at week 68 (P = 0.23). No statistically significant correlations were found between changes in body weight and Coll2-1 and Fib3-2 at any time point (r < 0.05; P > 0.49). At all time-points there were significant positive correlations between changes from baseline in Coll2-1 and in KOOSSports/Recreation (week 8, 16, 68: r = 0.17; P = 0.03; r = 0.16; P = 0.04; and r = 0.17; P = 0.04, respectively). CONCLUSION: The clinical improvement after a substantial weight loss and weight maintenance in KOA patients was not associated with decrease in markers of cartilage breakdown Coll2-1 or Fib3-2, even with indications of a slightly negative effect.

[Orthopaedic manual therapy : definition, characteristics and update on the situation in Belgium]. / La thérapie manuelle orthopédique : définition, caractéristiques et mise au point sur la situation en Belgique.

Although orthopaedic manual therapy (OMT) has existed for decades, and although a recent Belgian Royal Decree, published in 2014, recognized it as a particular professional qualification in physiotherapy for the treatment of neuromusculoskeletal dysfunctions, OMT remains little known by patients, but also by healthcare professionals. Yet, this professional qualification, based on clinical reasoning, using highly specific treatments, guided by the best available scientific and clinical evidence and the specific biopsychosocial characteristics of each patient, is the subject of a growing number of scientific studies pointing out its effectiveness. This article summarizes the knowledge related to OMT (definition, history, characteristics, techniques, indications, access and reimbursement) and describes its situation in Belgium.

Bien que la thérapie manuelle orthopédique (TMO) existe depuis des décennies et qu'un récent arrêté royal belge reconnaissant cette discipline comme une qualification professionnelle particulière en kinésithérapie pour la prise en charge des troubles neuro-musculo-squelettiques ait été publié en 2014, la TMO demeure méconnue des patients, mais également du monde médical. Pourtant, cette discipline, basée sur un raisonnement clinique, utilisant des approches thérapeutiques hautement spécifiques guidées par les meilleures évidences scientifiques et cliniques disponibles ainsi que par la spécificité biopsychosociale propre à chaque patient, fait l'objet d'un nombre croissant d'études scientifiques mettant en évidence son intérêt. Cet article vise à synthétiser les connaissances relatives à la TMO (sa définition, son historique, ses caractéristiques, ses techniques, ses indications, son accès et son remboursement, ainsi que son enseignement) en décrivant la situation en Belgique.

Chondrocyte secretome: a source of novel insights and exploratory biomarkers of osteoarthritis.

The extracellular matrix (ECM) of articular cartilage is comprised of complex networks of proteins and glycoproteins, all of which are expressed by its resident cell, the chondrocyte. Cartilage is a unique tissue given its complexity and ability to resist repeated load and deformation. The mechanisms by which articular cartilage maintains its integrity throughout our lifetime is not fully understood, however there are numerous regulatory pathways known to govern ECM turnover in response to mechanical stimuli. To further our understanding of this field, we envision that proteomic analysis of the secretome will provide information on how the chondrocyte remodels the surrounding ECM in response to load, in addition to providing information on the metabolic state of the cell. In this review, we attempt to summarize the recent mass spectrometry-based proteomic discoveries in healthy and diseased cartilage and chondrocytes, to facilitate the discovery of novel biomarkers linked to degenerative pathologies, such as osteoarthritis (OA).

Osteoarthritis biomarkers derived from cartilage extracellular matrix: Current status and future perspectives.

Specific soluble biomarkers can be powerful tools for the diagnosis, prognosis and personalized management of osteoarthritis (OA). Biomarkers are potential indicators of the effect of a drug on cartilage metabolism and provide crucial information about the mechanisms of drug action. In this review, we address key questions concerning the use of biomarkers in OA management: Why do we need soluble biomarkers? What are the most widely investigated biomarkers derived from cartilage extracellular matrix? What are the most common pitfalls in interpreting soluble biomarker measurements? What are the perspectives and future research directions in this field? We review current evidence to propose that cartilage-derived soluble biomarkers are complementary "drug development tools" that can be applied during drug development from preclinical research to clinical evaluation. In the future, such biomarkers could be surrogate markers of clinical and/or imaging outcomes. Successful standardization and implementation of automated biomarker assays will facilitate their use in companion diagnostics in the context of personalized medicine for enhanced management of OA.

[THE MALADAPTIVE BELIEFS OF PATIENTS WITH LOW BACK PAIN. A NARRATIVE REVIEW]. / LES CROYANCES DÉLÉTÈRES DES PATIENTS LOMBALGIQUES. Revue narrative de la literature.

OBJECTIVE: to summarize the knowledge regarding the maladaptive beliefs of patients with non-specific low back pain. METHODS: a narrative literature review on these beliefs was conducted by an international and multidisciplinary team of experts in the field. RESULTS: these beliefs, which can result in negative consequences on functioning and on patient prognosis, have various origins: family and friends, media, previous experience and/or health care professionals' messages. The latter, who have a considerable and enduring influence, have the potential to change and correct the patients' misbeliefs; however, they can also reinforce them in case of inappropriate messages and attitudes. Informing and educating the patient (by means of reassurance, explanations of the non-systematic association pain-injury, encouragement to get and stay physically active) are the basis of treatment. Taking into account the consequences of some words which may be misinterpreted, the results of imaging should be wisely discussed with the patient. Pain neurophysiology education and cognitive behavioral therapy (i.a., in vivo graded exposure techniques) are effective additional treatments. CONCLUSIONS: Misbeliefs are frequent in patient with low back pain. They do need to be looked for and corrected.

Fibulin-3 fragments are prognostic biomarkers of osteoarthritis incidence in overweight and obese women.

OBJECTIVE: To determine the association between three fibulin-3 peptides and the incidence of radiographic and clinical knee osteoarthritis (OA). DESIGN: Women between 50 and 60 years, with a BMI ≥27 kg/m(2), free of knee OA, were recruited. Using binary logistic regression, the association between baseline concentration of serum fibulin (Fib)3-1, Fib3-2 and Fib3-3 and incidence of clinical and radiographic knee OA after 30 months of follow-up was evaluated. RESULTS: Baseline and follow-up measurements were available for 241 women with a mean age of 55.9 ± 3.2 years and mean BMI of 31.7 ± 3.6 kg/m(2). None of the concentrations of the three Fib3 epitopes were associated with the incidence of medial or lateral joint space narrowing (JSN) ≥1.0 mm or the incidence of Kellgren & Lawrence (K&L) grade ≥2 after 30 months. All three Fib3 epitopes were associated with the incidence of the clinical and radiographic ACR-criteria and Fib3-1 and Fib3-3 also with chronic pain at follow-up. When adjusted for the other Fib3 peptide concentrations, only Fib3-1 was significantly associated to the incidence of the American College of Rheumatology (ACR)-criteria (OR 3.2 [1.2-8.7]) and chronic pain at follow-up (OR 3.0 [1.2-7.7]). CONCLUSIONS: Baseline fibulin-3 concentrations are associated with the incidence of clinical knee OA among middle-aged overweight and obese women. Therewith, they meet the criteria of a prognostic biomarker according to the BIPED biomarker classification for OA. Further validation of the fibulin-3 epitopes seems warranted in order to better distinguish subgroups of individuals at increased risk for knee OA development.

Osteoarthritis year in review 2015: soluble biomarkers and the BIPED criteria.

OBJECTIVE: To review and summarize biomarker data published from April 2014 to May 2015 to provide insight to the ongoing work in the field of osteoarthritis (OA). Furthermore, to summarize the BIPED criteria and set it in context of the medical needs of 2015. METHODS: PubMed was used as searching machine: Time period 2014/04/01-2015/05/01, MeSH term [Biomarker] AND [Osteoarthritis], Language; English, Full text available. Reviews were excluded. Only papers describing protein based biomarkers measured in human body fluids from OA patients were included. RESULTS: Biomarkers of joint tissue turnover, cytokines, chemokines and peptide arrays were measured in different cohorts and studies. Amongst those were previously tested biomarkers such as osteocalcin, Carboxy-terminal cross-linked fragment of type II collagen (CTX-II) and cartilage oligomeric matrix protein (COMP). A majority of the biomarker were classified as I, B or B biomarkers according to the BIPED criteria. Work is continuing on testing biomarkers in OA. There is still a huge, unmet medical need to identify, test, validate and qualify novel and well-known biomarkers. A pre-requisite for this is better characterization and classification of biomarkers to their needs, which may not be reached before higher understanding of OA phenotypes has been gained. In addition, we provide some references to some recent guidelines from Food and Drug Administration (FDA) and European Medicines Agency (EMA) on qualification and usage of biomarkers for drug development and personalized medicine, which may provide value to the field.

Review of dietary supplements for the management of osteoarthritis in dogs in studies from 2004 to 2014.

Osteoarthritis (OA) is a chronic, painful, degenerative and inflammatory disease that affects the synovial joints and leads finally to the loss of mobility. It is highly prevalent in dogs. Nowadays, no cure exists, and the pharmacological treatment is limited to clinical signs alleviation. Some positive beneficial effects have been highlighted with dietary supplements in the course of dog OA. The goals of this narrative review are to summarize the scientific data available in the literature on dietary supplements assessed in dog OA and to discuss some trails about how to improve several aspects of research and issues with dietary supplements, such as bioavailability and dosage regimen. Chondroitin sulphate, glucosamine, undenaturated type II collagen, avocado-soya bean unsaponifiables, curcumin and polyunsaturated fatty acids were studied in dog OA and therefore discussed in the present review. Most of them showed anticatabolic and anti-inflammatory effects. Unfortunately, few data exist concerning their pharmacokinetics. Their bioavailability is low, but new formulations are developed to enhance their gastrointestinal absorption. The clinical relevance of these new formulations compared to native forms should be demonstrated in good clinical trials. Even if further investigations are needed, dietary supplements should be considered in OA management.

Volition and low back pain: When patients talk.

OBJECTIVE: Our objective was to explore, describe and understand volition of chronic low back pain (LBP) patients, highlighting barriers and facilitators to practicing regular physical activity in order to develop a questionnaire assessing those volitional competencies. METHODS: A content analysis of semi-structured interviews with 30 chronic LBP patients was performed. Participants were asked about their pain, motivation, physical abilities, barriers and facilitators to regular exercises and finally strategies implemented to achieve the exercise program. RESULTS: Patients often reported that they were motivated and that exercises had no negative effects on LBP. Many patients recognized having difficulties performing all their exercises regularly. The main barriers were: lack of time, fatigue, lack of visible results, pain and other daily priorities. The main facilitators were: group exercise, help from the therapist, strategic planning, favorable environment, pleasure associated with exercises, fear of pain recurrence and pain itself. CONCLUSION: Content analysis showed that sharing stories allowed patients to express their experience of LBP in their own words. It provides a solid ground to develop a questionnaire assessing volitional competencies in chronic LBP patients in order to identify patients who will not realize their exercises and help them be (more) active and avoid chronicity.

OARSI Clinical Trials Recommendations: Soluble biomarker assessments in clinical trials in osteoarthritis.

The objective of this work was to describe requirements for inclusion of soluble biomarkers in osteoarthritis (OA) clinical trials and progress toward OA-related biomarker qualification. The Guidelines for Biomarkers Working Group, representing experts in the field of OA biomarker research from both academia and industry, convened to discuss issues related to soluble biomarkers and to make recommendations for their use in OA clinical trials based on current knowledge and anticipated benefits. This document summarizes current guidance on use of biomarkers in OA clinical trials and their utility at five stages, including preclinical development and phase I to phase IV trials. As demonstrated by this summary, biomarkers can provide value at all stages of therapeutics development. When resources permit, we recommend collection of biospecimens in all OA clinical trials for a wide variety of reasons but in particular, to determine whether biomarkers are useful in identifying those individuals most likely to receive clinically important benefits from an intervention; and to determine whether biomarkers are useful for identifying individuals at earlier stages of OA in order to institute treatment at a time more amenable to disease modification.

OARSI Clinical Trials Recommendations: Design, conduct, and reporting of clinical trials for knee osteoarthritis.

The goal of this document is to update the original OARSI recommendations specifically for the design, conduct, and reporting of clinical trials that target symptom or structure modification among individuals with knee osteoarthritis (OA). To develop recommendations for the design, conduct, and reporting of clinical trials for knee OA we initially drafted recommendations through an iterative process. Members of the working group included representatives from industry and academia. After the working group members reviewed a final draft, they scored the appropriateness for recommendations. After the members voted we calculated the median score among the nine members of the working group who completed the score. The document includes 25 recommendations regarding randomization, blocking and stratification, blinding, enhancing accuracy of patient-reported outcomes (PRO), selecting a study population and index knee, describing interventions, patient-reported and physical performance measures, structural outcome measures, biochemical biomarkers, and reporting recommendations. In summary, the working group identified 25 recommendations that represent the current best practices regarding clinical trials that target symptom or structure modification among individuals with knee OA. These updated recommendations incorporate novel technologies (e.g., magnetic resonance imaging (MRI)) and strategies to address the heterogeneity of knee OA.

OARSI Clinical Trials Recommendations: Design and conduct of clinical trials for hip osteoarthritis.

The ability to assess the efficacy and effectiveness of an intervention for the treatment of hip osteoarthritis (OA) requires strong clinical trial methodology. This consensus paper provides recommendations based on a narrative literature review and best judgment of the members of the committee for clinical trials of hip OA. We provide recommendations on clinical trial design, outcome measures, including structural (radiography), and patient and physician global assessments, performance based measures, molecular markers and experimental endpoints including MRI imaging. This information can be utilized by sponsors of trials for new therapeutic agents for hip OA.

OARSI Clinical Trials Recommendations: Design and conduct of clinical trials for hand osteoarthritis.

Hand osteoarthritis (OA) is a very frequent disease, but yet understudied. However, a lot of works have been published in the past 10 years, and much has been done to better understand its clinical course and structural progression. Despite this new knowledge, few therapeutic trials have been conducted in hand OA. The last OARSI recommendations for the conduct of clinical trials in hand OA dates back to 2006. The present recommendations aimed at updating previous recommendations, by incorporating new data. The purpose of this expert opinion, consensus driven exercise is to provide evidence-based guidance on the design, execution and analysis of clinical trials in hand OA, where published evidence is available, supplemented by expert opinion, where evidence is lacking, to perform clinical trials in hand OA, both for symptom and for structure-modification. They indicate core outcome measurement sets for studies in hand OA, and list the methods and instruments that should be used to measure symptoms or structure. For both symptom- and structure-modification, at least pain, physical function, patient global assessment, HR-QoL, joint activity and hand strength should be assessed. In addition, for structure-modification trials, structural progression should be measured by radiographic changes. We also provide a research agenda listing many unsolved issues that seem to most urgently need to be addressed from the perspective of performing "good" clinical trials in hand OA. These updated OARSI recommendations should allow for better standardizing the conduct of clinical trials in hand OA in the next future.

Association of urinary biomarker COLL2-1NO2 with incident clinical and radiographic knee OA in overweight and obese women.

OBJECTIVE: To investigate the association between urinary biomarker Coll2-1NO2 (uColl2-1NO2) and incident knee OA after 2.5 years follow-up in middle-aged overweight and obese women at high risk for knee osteoarthritis (OA). DESIGN: Data were used from PROOF, a randomized controlled trial with 2.5 years follow-up evaluating the preventive effects of a diet and exercise program and oral glucosamine sulphate (double blind and placebo controlled), on development of incident knee OA in women with body mass index ≥ 27 kg/m(2) without signs of knee OA at baseline. Baseline and 2.5 years uColl2-1NO2 concentrations were assessed with enzyme-linked immunosorbent assay (ELISA). Primary outcome measure was incidence of knee OA in one or both knees, defined as incidence of either Kellgren & Lawrence grade ≥2, joint space narrowing of ≥1.0 mm or knee OA according to the combined clinical and radiographic ACR-criteria. We used binary logistic regression for the association analyses. RESULTS: 254 women were available for analyses. At 2.5 years follow-up, incident knee OA was present in 72 of 254 women (28.3%). An inversed association was found between baseline uColl2-1NO2 and incident knee OA at 2.5 years (OR 0.74, 95% CI 0.55-0.99). The concentration at 2.5 years and the change in concentration over 2.5 years did not show significant associations with the outcome. CONCLUSIONS: In overweight and obese middle-aged women, not higher but lower baseline uColl2-1NO2 concentration was significantly associated with an increased risk for incident knee OA. This interesting but counterintuitive outcome makes further validation of this biomarker warranted.