Osteoarthritis is the third most rapidly growing health condition associated with disability, after dementia and diabetes¹. By 2050, the total number of patients with osteoarthritis is estimated to reach 1 billion worldwide². As no disease-modifying treatments exist for osteoarthritis, a better understanding of disease aetiopathology is urgently needed. Here we perform a genome-wide association study meta-analyses across up to 489,975 cases and 1,472,094 controls, establishing 962 independent associations, 513 of which have not been previously reported. Using single-cell multiomics data, we identify signal enrichment in embryonic skeletal development pathways. We integrate orthogonal lines of evidence, including transcriptome, proteome and epigenome profiles of primary joint tissues, and implicate 700 effector genes. Within these, we find rare coding-variant burden associations with effect sizes that are consistently higher than common frequency variant associations. We highlight eight biological processes in which we find convergent involvement of multiple effector genes, including the circadian clock, glial-cell-related processes and pathways with an established role in osteoarthritis (TGFβ, FGF, WNT, BMP and retinoic acid signalling, and extracellular matrix organization). We find that 10% of the effector genes express a protein that is the target of approved drugs, offering repurposing opportunities, which can accelerate translation.

The locomotive syndrome risk test was developed to quantify the decrease in mobility among adults, which could eventually lead to disability. The purpose of this study was to establish reference values for the locomotive syndrome risk test for adults and investigate the influence of age and sex. We analyzed 8681 independent community dwellers (3607 men, 5074 women). Data pertaining to locomotive syndrome risk test (the two-step test, the stand-up test, and the 25-question geriatric locomotive function scale [GLFS-25]) scores were collected from seven administrative areas of Japan. The reference values of the three test scores were generated and all three test scores gradually decreased among young-to-middle-aged individuals and rapidly decreased in individuals aged over 60 years. The stand-up test score began decreasing significantly from the age of 30 years. The trajectories of decrease in the two-step test score with age was slightly different between men and women especially among the middle-aged individuals. The two physical test scores were more sensitive to aging than the self-reported test score. The reference values generated in this study could be employed to determine whether an individual has mobility comparable to independent community dwellers of the same age and sex.

Introduction: While many of the commonly used conservative treatments for knee osteoarthritis (OA) have been recognized to be effective, there is still insufficient evidence available. Among the pharmacological treatments for knee OA, oral non-steroidal anti-inflammatory drugs (NSAIDs) act rapidly and are recommended for the management of OA. However, frequent and serious adverse effects of NSAIDs have been recognized. Intra-articular injections of hyaluronic acid (IA-HA) for the treatment of knee OA have been shown to reduce pain and improve joint function. However, there has been no qualified direct comparison study of the efficacy and safety between IA-HA and NSAIDs for patients with knee OA. The aim of this study was to clarify the efficacy and safety of early-phase IA-HA in comparison to those of NSAIDs for patients with knee OA. Methods: This multicenter, randomized, open-label, parallel-group, non-inferiority comparison study with an oral NSAID involved a total of 200 patients with knee OA. An independent, computer-generated randomization sequence was used to randomly assign patients in a 1:1 ratio to NSAIDs three times per day for five weeks (n = 100) or IA-HA once a week for five weeks (n = 100). The primary endpoint was the percentage change in the patient-oriented outcome measure for knee OA, the Japanese Knee Osteoarthritis Measure (JKOM) score. All patients were questioned regarding any adverse events during treatment. The full analysis set (FAS) was used for analysis. The margin of non-inferiority was 10%. Results: The analyses of primary endpoint included 98 patients in the IA-HA group and 86 patients in the NSAID group. The difference in the percentage changes of the JKOM score between the two intervention arms (IA-HA; -34.7% (P<0.001), NSAID; -32.2% (P<0.001)) was -2.5% (95% confidence interval (CI): -14.0 to 9.1), indicating IA-HA was not inferior to NSAID. The frequency of both withdrawal and adverse events in the IA-HA group were significantly lower than those in the NSAID group (P = 0.026 and 0.004, respectively). Conclusions: The early efficacy of IA-HA is suggested to be not inferior to that of NSAIDs, and that the safety of the early phase of IA-HA is superior to that of NSAIDs for patients with knee OA. Trial registration: UMIN Clinical Trials Registry (UMIN- CTR), UMIN000001026.

We previously reported, based on a multicenter randomized-control study, that the efficacy of intra-articular injections of hyaluronic acid (IA-HA) was not inferior to that of oral non-steroidal anti-inflammatory drugs (NSAIDs) in patients with knee osteoarthritis (OA). However, the molecular effects on the pathophysiology of knee OA remain unclear. C-terminal telopeptides of type II collagen (CTX-II) is reported to primarily originate from the interface between articular cartilage and subchondral bone, which is a site of potential remodeling in OA. We performed a predefined sub-analysis of the previous study to compare the changes of urinary CTX-II (uCTX-II) in response to IA-HA to those in response to NSAID for knee OA. A total of 200 knee OA patients were registered from 20 hospitals and randomized to receive IA-HA (2,700 kDa HA, 5 times at 1-week intervals) or NSAID (loxoprofen sodium, 180 mg/day) for 5 weeks. The uCTX-II levels were measured before and after treatment. The uCTX-II levels were significantly increased by IA-HA treatment (337.7 ± 193.8 to 370.7 ± 234.8 ng/μmol Cr) and were significantly reduced by NSAID treatment (423.2 ± 257.6 to 370.3 ± 250.9 ng/μmol Cr). The %changes of uCTX-II induced by IA-HA (11.6 ± 29.5%) and NSAID (-9.0 ± 26.7%) was significantly different (between-group difference: 20.6, 95% confidence intervals: 10.6 to 30.6). While both IA-HA and NSAID improved symptoms of knee OA, uCTX-II levels were increased by IA-HA and reduced by NSAIDs treatment, suggesting these treatments may improve symptoms of knee OA through different modes of action.