A genome-wide association study identifies 5 loci associated with frozen shoulder and implicates diabetes as a causal risk factor

Gastroesophageal reflux disease, mood swings, and frozen shoulder: A two-sample, two-step Mendelian randomization study

A Mendelian randomization (MR) study was undertaken to establish a causal link between gastroesophageal reflux disease (GERD) and frozen shoulder (FS), examining whether the risk of GERD with FS is mediated through mood fluctuations. Genetic loci from populations of independent European ancestry were selected as instrumental variables for GERD, FS, and mood swings. The primary analysis employed the inverse-variance weighted method supplemented by 3 additional analytical methods. This was conducted using two-sample and two-step MR analyses. This study explored the correlation and mediating effects of mood swings between GERD and FS. Our study employed heterogeneity and horizontal diversity, and sensitivity analysis was conducted using the leave-one-out method to explore the robustness of the results. In the two-sample MR analysis, for every 1-unit increase in the log-transformed odds ratio (OR) of GERD, the corresponding OR increased to 1.844 (inverse-variance weighting: OR = 1.844, 95% confidence interval: 1.47-2.30, P < .001). In the two-step MR analysis, we found that mood swings played a mediating role in the association between GERD and FS. We assessed this mediating effect using the delta method (b = 0.181, SE = 0.059, OR = 1.199, 95% confidence interval: 1.072-1.349). Analysis of the data using the above methods indicated that GERD is a risk factor for FS, and mood swings mediate between the 2. Therefore, GERD and mood swings should be included in the health management of patients with FS.

Impact of immune cells on the risk of frozen shoulder: A 2-sample Mendelian randomization study

The pathogenesis of frozen shoulder (FS) remains unclear, and current research primarily focuses on immune responses. Increasing evidence suggests that immune cells play a significant role in FS development. However, the causal relationship between the two remains poorly understood. Therefore, we aimed to investigate this using Mendelian randomization (MR) analysis. Single nucleotide polymorphisms closely associated with 731 immune phenotypes were obtained from publicly available GWAS datasets as instrumental variables. FS was used as the outcome with a sample size of 451,099 cases. Causal effects were analyzed using the inverse variance-weighted method. We conducted sensitivity tests, including the intercept of the MR-Egger and MR-PRESSO analyses. The presence of heterogeneity was evaluated using Cochran Q test. We identified potential causal relationships in terms of increased risk for FS with 5 immune phenotypes: CD25++ CD45RA+ CD4 not regulatory T cell %CD4+ T cells (odds ratio [OR] = 1.0273, 95% confidence interval [CI]: 1.0093-1.0457, P = .0028), CD25++ CD45RA+ CD4 not regulatory T cell %T cell (OR = 1.0240, 95% CI: 1.0057-1.0427, P = .0098), CD127 on CD28+ CD4+ T cells (OR = 1.0398, 95% CI: 1.0121-1.0682, P = .0046), CD4 on human leukocyte antigen DR+ CD4+ T cells (OR = 1.0795, 95% CI: 1.0316-1.2195, P = .0009), and human leukocyte antigen DR on CD14- CD16+ monocytes (OR = 1.0533, 95% CI: 1.0136-1.0945, P = .0081). Few significant heterogeneities or horizontal pleiotropies were observed. Through MR analysis, we identified distinct 5 types of immune cells that were positively correlated with the occurrence and development of FS, providing guidance for clinical intervention in FS.

A Narrative Review of Adhesive Capsulitis with Diabetes

Background/Objectives: To update the perspectives of the association between diabetes (DM) and adhesive capsulitis (AC). Methods: Our findings were summarized in a narrative review. We searched PubMed, Embase, and Consensus databases, using keywords such as "diabetes", "adhesive capsulitis", and "frozen shoulder", for articles published from January 2015 to June 2024, covering both type 1 and type 2 DM. Results: After compiling relevant articles on DM-related AC published since 2015, we found that most studies show an increased prevalence of AC in DM patients, ranging from 3 to 10 times. A longer duration of DM is a risk factor for AC. Whether T1DM or prolonged insulin use will increase the risk of AC is still controversial. Poor blood sugar control seems to increase the risk of AC. Recent studies also show a correlation between blood sugar levels and the prevalence of AC. Cytokines, such as IL-6, IL-8, TNF-α, VEGF, and AGEs, related to inflammation and fibrosis may contribute to the pathophysiological processes of AC. Conclusions: Recent research findings have revealed new perspectives divergent from past notions, while also presenting some topics worthy of exploration. Due the close relationship between DM and AC, clinicians need to be alert to the presence of AC, especially early stage, in DM cases, and control the blood glucose level to reduce the risk of AC. Further research is still needed to provide better prevention and management for DM patients with AC.

Causal associations of hypothyroidism with frozen shoulder: a two-sample bidirectional Mendelian randomization study

BACKGROUND

Many studies have investigated the association between hypothyroidism and frozen shoulder, but their findings have been inconsistent. Furthermore, earlier research has been primarily observational, which may introduce bias and does not establish a cause-and-effect relationship. To ascertain the causal association, we performed a two-sample bidirectional Mendelian randomization (MR) analysis.

METHODS

We obtained data on "Hypothyroidism" and "Frozen Shoulder" from Summary-level Genome-Wide Association Studies (GWAS) datasets that have been published. The information came from European population samples. The primary analysis utilized the inverse-variance weighted (IVW) method. Additionally, a sensitivity analysis was conducted to assess the robustness of the results.

RESULTS

We ultimately chose 39 SNPs as IVs for the final analysis. The results of the two MR methods we utilized in the investigation indicated that a possible causal relationship between hypothyroidism and frozen shoulder. The most significant analytical outcome demonstrated an odds ratio (OR) of 1.0577 (95% Confidence Interval (CI):1.0057-1.1123), P = 0.029, using the IVW approach. Furthermore, using the MR Egger method as a supplementary analytical outcome showed an OR of 1.1608 (95% CI:1.0318-1.3060), P = 0.017. Furthermore, the results of our sensitivity analysis indicate that there is no heterogeneity or pleiotropy in our MR analysis. In the reverse Mendelian analysis, no causal relationship was found between frozen shoulders and hypothyroidism.

CONCLUSION

Our MR analysis suggests that there may be a causal relationship between hypothyroidism and frozen shoulder.

Genetic insights into the association between serum cytokines and frozen shoulder risk: A bidirectional mendelian randomization study

BACKGROUND

Although existing studies have indicated a connection between chronic low-grade inflammation and the onset of frozen shoulder (FS), the precise causal relationship between distinct circulating inflammatory factors and FS has yet to be thoroughly evaluated. In this study, we employed a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the potential causal relationship between systemic cytokines and FS.

METHODS

A genome-wide association dataset comprising 41 serum cytokines from 8,293 individuals of Finnish descent was utilized, along with FS data from the UK Biobank included 10,104 FS cases and 451,099 controls. The primary MR method was the inverse variance weighted approach, and four additional MR techniques (MR-Egger, weighted median, simple mode, and weighted mode) were also employed to support and validate the findings. Heterogeneity and horizontal pleiotropy assessments were assessed using Cochrane's Q and MR-Egger intercept tests. Moreover, a series of sensitivity analyses were conducted to strengthen the accuracy and credibility of these findings.

RESULTS

Based on the IVW method, genetically predicted increasing levels of growth regulated oncogene alpha (GROa) (OR=1.08, 95 % CI 1.02-1.13, P=0.005), interferon gamma-induced protein 10 (IP-10) (OR=1.09, 95 % CI 1.02-1.17, P=0.010), regulated on activation, C-C Motif Chemokine Ligand 5 (CCL5) (OR=1.11, 95 % CI 1.03-1.20, P=0.007) were suggestively associated with an increased risk of FS. Reverse MR analysis revealed no significant causal effect of FS on the 41 systemic inflammatory factors. No heterogeneity or horizontal pleiotropy was observed in our analysis.

CONCLUSION

This study established a causal association between 41 systemic inflammatory factors and FS, indicating that elevated levels of GROa, IP-10 and CCL5 were associated with a higher risk of FS. Further research is warranted to explore the potential of these biomarkers as early predictors and therapeutic targets for FS.

Risk factors and predictive models for frozen shoulder

This study aims to explore the risk factors associated with frozen shoulder (FS) and develop a predictive model for diagnosing FS, in order to facilitate early detection of the condition. A total of 103 patients diagnosed with FS and admitted to the Department of Joint Surgery at Suining Central Hospital between October 2021 and October 2023 were consecutively included in the study. Additionally, 309 individuals without shoulder joint diseases, matched for age and gender, who visited the department during the same time, were included as the control group.The complete recording of clinical data for all patients was followed by the utilization of statistical tests such as the Mann-Whitney U test, sample t test, and chi-square test to compare different groups. Additionally, multivariate binary logistic regression analysis was employed to identify risk factors associated with the occurrence of FS in patients, leading to the establishment of a prediction model and derivation of a simplified equation. The diagnostic effectiveness of individual indicators and prediction models was assessed through the use of receiver operating characteristic (ROC) curve analysis. In the sample of 103 individuals, 35 were identified as male and 68 as female, with an average age range of 40-70 years (mean age: 54.20 ± 6.82 years). The analysis conducted between different groups revealed that individuals with a low body mass index (BMI), in conjunction with other factors such as diabetes, cervical spondylosis, atherosclerosis, and hyperlipidemia, were more susceptible to developing FS. Logistic regression analysis further indicated that low BMI, diabetes, cervical spondylosis, and hyperlipidemia were significant risk factors for the occurrence of FS. These variables were subsequently incorporated into a predictive model, resulting in the creation of a simplified equation.The ROC curve demonstrated that the combined indicators in the predictive model exhibited superior diagnostic efficacy compared to single indicators, as evidenced by an area under the curve of 0.787, sensitivity of 62.1%, and specificity of 82.2%. Low BMI, diabetes, cervical spondylosis, and hyperlipidemia are significant risk factors associated with the occurrence of FS. Moreover, the utilization of a prediction model has demonstrated superior capability in forecasting the likelihood of FS compared to relying solely on individual indicators. This finding holds potential in offering valuable insights for the early diagnosis of FS.

Causal relationships between systemic inflammatory cytokines and adhesive capsulitis: a bidirectional Mendelian randomization study

Background

Mounting evidence suggests a connection between inflammatory cytokines and adhesive capsulitis (AC). However, the specific systemic inflammatory cytokines contributing to AC have not been clearly identified. This study employed Mendelian randomization (MR) to explore the causal relationships between 41 inflammatory cytokines and AC.

Methods

In this bidirectional, two-sample MR analysis, genetic variations associated with AC were derived from a comprehensive genome-wide association study (GWAS). The inflammatory cytokines data were sourced from a GWAS summary involving 8,293 healthy participants. The primary MR method employed was inverse variance weighting, supplemented by MR-Egger, weighted median, and MR-pleiotropy residual sum and outlier for sensitivity analysis. Heterogeneity was assessed using Cochran's Q test, and the MR results were validated using the leave-one-out method.

Results

Elevated levels of interferon gamma-induced protein 10 (IP-10) (odds ratio (OR) = 1.086, 95% confidence interval (CI) = 1.002-1.178) and regulated on activation, normal T cell expressed and secreted (RANTES) (OR = 1.107, 95% CI = 1.026-1.195) were linked to an increased risk of AC. Increased levels of stromal cell-derived factor-1 alpha (SDF-1α) (OR = 0.879, 95% CI = 0.793-0.974) and tumor necrosis factor-alpha (TNF-α) (OR = 0.911, 95% CI = 0.831-0.999) were associated with a reduced AC risk. Moreover, genetically predicted AC exhibited associations with elevated cutaneous T cell attracting (CTACK) levels (OR = 1.202, 95% CI = 1.007-1.435) and diminished levels of interleukin-17 (IL-17) (OR = 0.678, 95% CI = 0.518-0.888) and interleukin-5 (IL-5) (OR = 0.786, 95% CI = 0.654-0.944), as confirmed through inverse-variance weighted (IVW) methods.

Conclusion

The present study successfully establishes a causal association between genetically proxied circulating levels of IP-10, RANTES, SDF-1α, and TNF-α and the risk of AC. Additionally, AC contributes to an increase in CTACK and a decrease in IL-17 and IL-5. This significant finding not only enhances the understanding of the pathogenesis of AC but also holds promise for the development of effective clinical management strategies.

Psychological distress and uterine fibroids: a bidirectional two-sample mendelian randomization study

BACKGROUND

Observational data indicates a connection between emotional discomfort, such as anxiety and depression, and uterine fibroids (UFs). However, additional investigation is required to establish the causal relationship between them. Hence, we assessed the reciprocal causality between four psychological disorders and UFs utilizing two-sample Mendelian randomization (MR).

METHODS

To evaluate the causal relationship between four types of psychological distress (depressive symptoms, severe depression, anxiety or panic attacks, mood swings) and UFs, bidirectional two-sample MR was employed, utilizing single nucleotide polymorphisms (SNPs) associated with these conditions. Both univariate MR (UVMR) and multivariate MR (MVMR) primarily applied inverse variance weighted (IVW) as the method for estimating potential causal effects. Complementary approaches such as MR Egger, weighted median, simple mode, and weighted mode were utilized to validate the findings. To assess the robustness of our MR results, we conducted sensitivity analyses using Cochran's Q-test and the MR Egger intercept test.

RESULTS

The results of our UVMR analysis suggest that genetic predispositions to depressive symptoms (Odds Ratio [OR] = 1.563, 95% Confidence Interval [CI] = 1.209-2.021, P = 0.001) and major depressive disorder (MDD) (OR = 1.176, 95% CI = 1.044-1.324, P = 0.007) are associated with an increased risk of UFs. Moreover, the IVW model showed a nominally significant positive correlation between mood swings (OR: 1.578; 95% CI: 1.062-2.345; P = 0.024) and UFs risk. However, our analysis did not establish a causal relationship between UFs and the four types of psychological distress. Even after adjusting for confounders like body mass index (BMI), smoking, alcohol consumption, and number of live births in the MVMR, the causal link between MDD and UFs remained significant (OR = 1.217, 95% CI = 1.039-1.425, P = 0.015).

CONCLUSIONS

Our study presents evidence supporting the causal relationship between genetic susceptibility to MDD and the incidence of UFs. These findings highlight the significance of addressing psychological health issues, particularly depression, in both the prevention and treatment of UFs.

Patient experiences of hydrodistension as a treatment for frozen shoulder: A longitudinal qualitative study

BACKGROUND

Frozen shoulder is a condition associated with severe shoulder pain and loss of function impacting on a persons' physical and mental health. Hydrodistension treatment that has been widely adopted within the UK National Health Service for the condition. However, evidence of clinical effectiveness and understanding of the patient experiences of this treatment are lacking. This study explored the experiences of people with a frozen shoulder who received hydrodistension treatment.

METHODS

A qualitative design with repeat semi-structured interviews was used to explore participants' experiences of hydrodistension treatment. Participants were interviewed 2-4 weeks and again at 8-10 weeks after treatment. Interviews were audio-recorded and transcribed verbatim. Findings were analysed using an inductive thematic analysis framework. The study is reported in accordance with the consolidated criteria for reporting qualitative (COREQ) research.

RESULTS

15 participants were interviewed online or over the phone. Three themes were identified: 'Preparing for and having a hydrodistension', 'Physiotherapy after hydrodistension', and 'Outcome of hydrodistension '. Participants believed hydrodistension would benefit them, was well tolerated by many, and the effects were apparent to most within the first week. Physiotherapy still seemed to be valued to support recovery beyond this timepoint, despite these early effects. Some participant's experienced harms including severe procedural pain and blood sugar dysregulation.

CONCLUSION

This is the first study to investigate the experiences of people who undergo hydrodistension for frozen shoulder. Hydrodistension appears an acceptable treatment to participants with a frozen shoulder, acceptability is enhanced through adequate shared decision making. Further high-quality research is required to understand the comparative effectiveness of hydrodistension as a treatment for frozen shoulder, including adverse events, and the benefit of treatment by a physiotherapist after hydrodistension.

Gene association analysis to determine the causal relationship between immune-mediated inflammatory diseases and frozen shoulder

Multiple studies have indicated a potential correlation between immune-mediated inflammatory diseases (IMIDs) and Frozen shoulder (FS). To explore the genetic causal relationship between IMIDs and FS using 2-sample Mendelian randomization (MR) analysis. Genome-wide association study (GWAS) summary data for FS were obtained from Green's study, while data for 10 IMIDs were sourced from the FinnGen Consortium. The MR analysis was performed using inverse variance weighting, MR Egger, and weighted median methods. IVW, as the primary MR analysis technique, was complemented with other sensitivity analyses to validate the robustness of the results. Additionally, reverse MR analysis was further conducted to investigate the presence of reverse causal relationships. In the forward MR analysis, genetically determined 4 IMIDs are causally associated with FS: rheumatoid arthritis (odds ratio [OR] (95% confidence interval [95% CI]) = 1.05 [1.02-1.09], P < .01); type 1 diabetes (OR [95% CI] = 1.06 [1.03-1.09], P < .01); hypothyroidism (OR [95% CI] = 1.07 [1.01-1.14], P = .02); and Celiac disease (OR [95% CI] = 1.02 [1.01-1.04], P = .01). However, no causal relationship was found between 6 IMIDs (autoimmune hyperthyroidism, Crohn disease, ulcerative colitis, psoriasis, sicca syndrome and systemic lupus erythematosus) and FS. Sensitivity analyses did not detect any heterogeneity or horizontal pleiotropy. In the reverse MR analysis, no causal relationship was observed between FS and IMIDs. In conclusion, this MR study suggests a potential causal relationship between rheumatoid arthritis, type 1 diabetes, hypothyroidism, and Celiac disease in the onset and development of FS. Nevertheless, more basic and clinical research will be needed in the future to support our findings.

Unveiling potential therapeutic targets for diabetes-induced frozen shoulder through Mendelian randomization analysis of the human plasma proteome

INTRODUCTION

This study aimed to assess the causal relationship between diabetes and frozen shoulder by investigating the target proteins associated with diabetes and frozen shoulder in the human plasma proteome through Mendelian randomization (MR) and to reveal the corresponding pathological mechanisms.

RESEARCH DESIGN AND METHODS

We employed the MR approach for the purposes of establishing: (1) the causal link between diabetes and frozen shoulder; (2) the plasma causal proteins associated with frozen shoulder; (3) the plasma target proteins associated with diabetes; and (4) the causal relationship between diabetes target proteins and frozen shoulder causal proteins. The MR results were validated and consolidated through colocalization analysis and protein-protein interaction network.

RESULTS

Our MR analysis demonstrated a significant causal relationship between diabetes and frozen shoulder. We found that the plasma levels of four proteins were correlated with frozen shoulder at the Bonferroni significance level (p<3.03E-5). According to colocalization analysis, parathyroid hormone-related protein (PTHLH) was moderately correlated with the genetic variance of frozen shoulder (posterior probability=0.68), while secreted frizzled-related protein 4 was highly correlated with the genetic variance of frozen shoulder (posterior probability=0.97). Additionally, nine plasma proteins were activated during diabetes-associated pathologies. Subsequent MR analysis of nine diabetic target proteins with four frozen shoulder causal proteins indicated that insulin receptor subunit alpha, interleukin-6 receptor subunit alpha, interleukin-1 receptor accessory protein, glutathione peroxidase 7, and PTHLH might contribute to the onset and progression of frozen shoulder induced by diabetes.

CONCLUSIONS

Our study identified a causal relationship between diabetes and frozen shoulder, highlighting the pathological pathways through which diabetes influences frozen shoulder.

An Updated Overview of Risk Factors for Shoulder Stiffness

A painful reduction in shoulder mobility, known as "shoulder stiffness", can occur both as a primary idiopathic condition and as a secondary condition, for example, following surgical procedures. Various factors can contribute to the development of primary shoulder stiffness. In this review we summarize the pathophysiological mechanisms, genetic influences, endocrine disorders, metabolic conditions, as well as other diseases and medical-therapeutic approaches that might have an impact on the development of primary shoulder stiffness.

A single cell atlas of frozen shoulder capsule identifies features associated with inflammatory fibrosis resolution

Frozen shoulder is a spontaneously self-resolving chronic inflammatory fibrotic human disease, which distinguishes the condition from most fibrotic diseases that are progressive and irreversible. Using single-cell analysis, we identify pro-inflammatory MERTKlowCD48+ macrophages and MERTK + LYVE1 + MRC1+ macrophages enriched for negative regulators of inflammation which co-exist in frozen shoulder capsule tissues. Micro-cultures of patient-derived cells identify integrin-mediated cell-matrix interactions between MERTK+ macrophages and pro-resolving DKK3+ and POSTN+ fibroblasts, suggesting that matrix remodelling plays a role in frozen shoulder resolution. Cross-tissue analysis reveals a shared gene expression cassette between shoulder capsule MERTK+ macrophages and a respective population enriched in synovial tissues of rheumatoid arthritis patients in disease remission, supporting the concept that MERTK+ macrophages mediate resolution of inflammation and fibrosis. Single-cell transcriptomic profiling and spatial analysis of human foetal shoulder tissues identify MERTK + LYVE1 + MRC1+ macrophages and DKK3+ and POSTN+ fibroblast populations analogous to those in frozen shoulder, suggesting that the template to resolve fibrosis is established during shoulder development. Crosstalk between MerTK+ macrophages and pro-resolving DKK3+ and POSTN+ fibroblasts could facilitate resolution of frozen shoulder, providing a basis for potential therapeutic resolution of persistent fibrotic diseases.

Hyperglycaemia is a causal risk factor for upper limb pathologies

BACKGROUND

Diabetes (regardless of type) and obesity are associated with a range of musculoskeletal disorders. The causal mechanisms driving these associations are unknown for many upper limb pathologies. We used genetic techniques to test the causal link between glycemia, obesity and musculoskeletal conditions.

METHODS

In the UK Biobank's unrelated European cohort (N = 379 708) we performed mendelian randomisation (MR) analyses to test for a causal effect of long-term high glycaemia and adiposity on four musculoskeletal pathologies: frozen shoulder, Dupuytren's disease, carpal tunnel syndrome and trigger finger. We also performed single-gene MR using rare variants in the GCK gene.

RESULTS

Using MR, we found evidence that long-term high glycaemia has a causal role in the aetiology of upper limb conditions. A 10-mmol/mol increase in genetically predicted haemoglobin A1C (HbA1c) was associated with frozen shoulder: odds ratio (OR) = 1.50 [95% confidence interval (CI), 1.20-1.88], Dupuytren's disease: OR = 1.17 (95% CI, 1.01-1.35), trigger finger: OR = 1.30 (95% CI, 1.09-1.55) and carpal tunnel syndrome: OR = 1.20 (95% CI, 1.09-1.33). Carriers of GCK mutations have increased odds of frozen shoulder: OR = 7.16 (95% CI, 2.93-17.51) and carpal tunnel syndrome: OR = 2.86 (95% CI, 1.50-5.44) but not Dupuytren's disease or trigger finger. We found evidence that an increase in genetically predicted body mass index (BMI) of 5 kg/m2 was associated with carpal tunnel syndrome: OR = 1.13 (95% CI, 1.10-1.16) and associated negatively with Dupuytren's disease: OR = 0.94 (95% CI, 0.90-0.98), but no evidence of association with frozen shoulder or trigger finger. Trigger finger (OR 1.96 (95% CI, 1.42-2.69) P = 3.6e-05) and carpal tunnel syndrome [OR 1.63 (95% CI, 1.36-1.95) P = 8.5e-08] are associated with genetically predicted unfavourable adiposity increase of one standard deviation of body fat.

CONCLUSIONS

Our study consistently demonstrates a causal role of long-term high glycaemia in the aetiology of upper limb musculoskeletal conditions. Clinicians treating diabetes patients should be aware of these complications in clinic, specifically those managing the care of GCK mutation carriers. Upper limb musculoskeletal conditions should be considered diabetes complications.

Type 2 diabetes and fasting glycemic traits are causal factors of frozen shoulder: a 2-sample Mendelian randomization analysis

BACKGROUND

The causal relationship between type 2 diabetes (T2D) and frozen shoulder is unclear. This study aims to explore the genetic causal association between T2D and glycemic traits (fasting glucose [FG], fasting insulin [FI], glycated hemoglobin [HbA1c], and 2-hour postprandial glucose [2hGlu]) on frozen shoulder.

METHODS

Using 2-sample Mendelian randomization (MR), we analyzed nonconfounded estimates of the effects of T2D and glycemic traits on frozen shoulder. Single-nucleotide polymorphisms (SNPs) strongly associated (P < 5 × 10-8) with exposures from genome-wide association studies (GWAS) were identified. We employed fixed effect mode inverse variance weighting (IVW-FE), random effect mode IVW (IVW-MRE), MR-Egger, and weighted median to assess the association of exposures and outcome. Sensitivity analysis was conducted to test for heterogeneity and multidirectionality bias in MR.

RESULTS

We found a significant genetic causal correlation between T2D (IVW-MRE P = .007, odds ratio [OR] 1.093, 95% confidence interval [CI] 1.03-1.16), FG (IVW-FE P < .001, OR 1.455, 95% CI 1.173-1.806), and frozen shoulder, but no evidence for causal correlation between FI, HbA1c, and 2hGlu and frozen shoulder. Although there was certain heterogeneity, sensitivity analysis reveals no deviation from the MR assumptions.

CONCLUSION

This study supports a genetic causal relationship between T2D and FG and frozen shoulder.

A genome-wide association meta-analysis implicates Hedgehog and Notch signaling in Dupuytren's disease

Dupuytren's disease (DD) is a highly heritable fibrotic disorder of the hand with incompletely understood etiology. A number of genetic loci, including Wnt signaling members, have been previously identified. Our overall aim was to identify novel genetic loci, to prioritize genes within the loci for functional studies, and to assess genetic correlation with associated disorders. We performed a meta-analysis of six DD genome-wide association studies from three European countries and extensive bioinformatic follow-up analyses. Leveraging 11,320 cases and 47,023 controls, we identified 85 genome-wide significant single nucleotide polymorphisms in 56 loci, of which 11 were novel, explaining 13.3-38.1% of disease variance. Gene prioritization implicated the Hedgehog and Notch signaling pathways. We also identified a significant genetic correlation with frozen shoulder. The pathways identified highlight the potential for new therapeutic targets and provide a basis for additional mechanistic studies for a common disorder that can severely impact hand function.

Integrating External Controls by Regression Calibration for Genome-Wide Association Study

Genome-wide association studies (GWAS) have successfully revealed many disease-associated genetic variants. For a case-control study, the adequate power of an association test can be achieved with a large sample size, although genotyping large samples is expensive. A cost-effective strategy to boost power is to integrate external control samples with publicly available genotyped data. However, the naive integration of external controls may inflate the type I error rates if ignoring the systematic differences (batch effect) between studies, such as the differences in sequencing platforms, genotype-calling procedures, population stratification, and so forth. To account for the batch effect, we propose an approach by integrating External Controls into the Association Test by Regression Calibration (iECAT-RC) in case-control association studies. Extensive simulation studies show that iECAT-RC not only can control type I error rates but also can boost statistical power in all models. We also apply iECAT-RC to the UK Biobank data for M72 Fibroblastic disorders by considering genotype calling as the batch effect. Four SNPs associated with fibroblastic disorders have been detected by iECAT-RC and the other two comparison methods, iECAT-Score and Internal. However, our method has a higher probability of identifying these significant SNPs in the scenario of an unbalanced case-control association study.

Big data, big consortia, and pain: UK Biobank, PAINSTORM, and DOLORisk

Chronic pain (CP) is a common and often debilitating disorder that has major social and economic impacts. A subset of patients develop CP that significantly interferes with their activities of daily living and requires a high level of healthcare support. The challenge for treating physicians is in preventing the onset of refractory CP or effectively managing existing pain. To be able to do this, it is necessary to understand the risk factors, both genetic and environmental, for the onset of CP and response to treatment, as well as the pathogenesis of the disorder, which is highly heterogenous. However, studies of CP, particularly pain with neuropathic characteristics, have been hindered by a lack of consensus on phenotyping and data collection, making comparisons difficult. Furthermore, existing cohorts have suffered from small sample sizes meaning that analyses, especially genome-wide association studies, are insufficiently powered. The key to overcoming these issues is through the creation of large consortia such as DOLORisk and PAINSTORM and biorepositories, such as UK Biobank, where a common approach can be taken to CP phenotyping, which allows harmonisation across different cohorts and in turn increased study power. This review describes the approach that was used for studying neuropathic pain in DOLORisk and how this has informed current projects such as PAINSTORM, the rephenotyping of UK Biobank, and other endeavours. Moreover, an overview is provided of the outputs from these studies and the lessons learnt for future projects.

Exploring the potential relationship between frozen shoulder and Dupuytren's disease through bioinformatics analysis and machine learning

Background

Frozen shoulder (FS) and Dupuytren's disease (DD) are two closely related diseases, but the mechanism of their interaction is unknown. Our study sought to elucidate the molecular mechanism of these two diseases through shared gene and protein interactions.

Methods

GSE75152 and GSE140731 data were downloaded from the Gene Expression Omnibus (GEO) database, and shared genes between FS and DD were selected by using R packages. Then, we used Cytoscape software and the STRING database to produce a protein-protein interaction (PPI) network. Important interaction networks and hub genes were selected through MCODE and cytoHubba algorithms. To explore the potential mechanisms of the development of the two diseases, the hub genes were further enriched by GO and KEGG analyses. We predicted the transcription factors (TFs) of hub genes with Transcriptional Regulatory Relationships Unraveled by Sentence-based Text mining (TRRUST). Moreover, we identified candidate genes for FS with DD with cytoHubba and machine learning algorithms. Finally, we analyzed the role of immunocyte infiltration in FS and constructed the relationship between candidate genes and immunocytes in FS.

Results

We identified a total of 321 shared genes. The results of GO and KEGG enrichment of shared genes showed that extracellular matrix and collagen fibril tissue play a certain role in the occurrence and development of disease. According to the importance of genes, we constructed the key PPI network of shared genes and the top 15 hub genes for FS with DD. Then, we predicted that five TFs are related to the hub genes and are highly expressed in the FS group. Machine learning results show that the candidate genes POSTN and COL11A1 may be key for FS with DD. Finally, immune cell infiltration revealed the disorder of immunocytes in FS patients, and expression of candidate genes can affect immunocyte infiltration.

Conclusion

We identified a PPI network, 15 hub genes, and two immune-related candidate genes (POSTN and COL11A1) using bioinformatics analysis and machine learning algorithms. These genes have the potential to serve as diagnostic genes for FS in DD patients. Furthermore, our study reveals disorder of immunocytes in FS.

Causal relationship between ischemic stroke and its subtypes and frozen shoulder: a two-sample Mendelian randomization analysis

Background

Previous epidemiological and other studies have shown an association between ischemic stroke (IS) and frozen shoulder (FS). However, the causal relationship between them remains unclear. Therefore, the present study aimed to investigate the causal relationship between IS and FS using a two-sample Mendelian randomization method.

Methods

Our research was divided into two stages: discovery and replication. The data were extracted from publicly available genome-wide association studies (GWAS). We selected a large sample of IS (n = 440, 328) and its subtypes (large-artery atherosclerotic stroke (LAS), cardioembolic stroke (CES), and stroke caused by small-vessel disease (SVS) and lacunar stroke (n = 254, 959) as exposure data. Additionally, we selected a large sample of FS as outcome data (n = 451, 099). Inverse variance weighting (IVW) was applied as the primary analysis method. The weighted median, MR-Egger, simple model, and weighted model were used as complementary analysis methods to assess causal effects. Moreover, heterogeneity was analyzed using Cochran's Q-test with IVW and MR-Egger. The MR-Egger intercept and MR-PRESSO analysis methods were used for pleiotropy testing. The stability of the results was also assessed using a leave-one-out analysis.

Results

In the discovery stage, the IVW approach revealed an odds ratio (OR) of 1.207 with a 95% confidence interval (CI) of 1.027-1.417 and a P-value of 0.022. This suggests a causal association between IS levels and an increased risk of FS. In the subtype studies of IS, the findings were negative. However, during the replication stage, a significant causal link was found between selected lacunar strokes and FS with an OR of 1.252, a 95% CI of 1.105-1.419, and a P-value of 0.0004. All studies had no pleiotropy or heterogeneity, and the findings were robust.

Conclusions

Our study confirmed the causal relationship between any IS level and increased risk of FS. Furthermore, the same results were obtained in the replication stage with lacunar stroke as an exposure factor. However, there was no direct causal relationship between the subtypes of IS and FS. Our study provides theoretical support for shoulder care for patients with IS.

Prognostic factors associated with improvements in patient-reported outcomes in idiopathic adhesive capsulitis

Background

The purpose of this study was to identify prognostic factors that are associated with improvements in patient-reported outcomes measures (PROMs) related to upper extremity function and pain in those suffering from idiopathic adhesive capsulitis.

Methods

All patients treated conservatively for primary idiopathic adhesive capsulitis were identified from our institutional database between 2019 and 2021. Exclusion criteria included any patients treated surgically, follow-up less than one year, or incomplete survey results. PROMs including Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity Computer Adaptive Test Version 2.0 (P-UE), Pain Interference (P-Interference), Pain Intensity (P-Intensity), and visual analog scale (VAS) pain scores. They were obtained at initial consultation and at one year to assess patient-perceived impact of their condition. Multiple linear and multivariable logistic regressions were performed to identify factors associated with improvement in patient-perceived pain and shoulder function using final PROM scores and difference in PROM scores from initial consultation. An independent t-test was used to compare baseline and one-year minimum follow-up PROMs. Odds ratios and their 95% confidence intervals were calculated for each factor; a P value of < .05 was considered statistically significant.

Results

A total of 56 patients (40 females and 16 males) were enrolled in the study with an average age of 54.7 ± 7.7 years. A significant improvement (P < .001) was demonstrated at one-year minimum outcomes for P-UE, P-Interference, P-Intensity, and VAS scores. With respect to comorbid conditions, hypothyroidism [P-UE (β: 9.57, P = .006)] was associated with greater improvements in PROMs, while hyperlipidemia [P-UE (β: -4.13, P = .01) and P-Intensity (β: 2.40, P = .02)] and anxiety [P-UE (β: -4.13, P = .03)] were associated with poorer reported changes in PROMs. Female sex [P-UE (β: 4.03, P = .007) and P-Interference (β: -2.65, P = .04)] and employment in manual labor professions [P-Interference (β: -3.07, P = .01), P-Intensity (β: -2.92, P = .006), and VAS (β: -0.66, P = .03)] were associated with significantly better patient-perceived outcomes. Hispanic heritage was associated with higher reported changes of P-Intensity (β: 8.45, P = .004) and VAS (β: 2.65, P = .002).

Conclusion

Patient-perceived improvements in PROMIS score during the natural history of adhesive capsulitis are likely multifactorial, with anxiety, hyperlipidemia, increased body mass index, and Hispanic heritage associated with reduced improvement in PROMIS scores.

Genome-Wide Association Study of Adhesive Capsulitis Suggests Significant Genetic Risk Factors

BACKGROUND

Adhesive capsulitis of the shoulder involves loss of passive range of motion with associated pain and can develop spontaneously, with no obvious injury or inciting event. The pathomechanism of this disorder remains to be elucidated, but known risk factors for adhesive capsulitis include diabetes, female sex, and thyroid dysfunction. Additionally, transcriptional profiling and pedigree analyses have suggested a role for genetics. Identification of elements of genetic risk for adhesive capsulitis using population-based techniques can provide the basis for guiding both the personalized treatment of patients based on their genetic profiles and the development of new treatments by identification of the pathomechanism.

METHODS

A genome-wide association study (GWAS) was conducted using the U.K. Biobank (a collection of approximately 500,000 patients with genetic data and associated ICD-10 [International Classification of Diseases, 10th Revision] codes), comparing 2,142 patients with the ICD-10 code for adhesive capsulitis (M750) to those without. Separate GWASs were conducted controlling for 2 of the known risk factors of adhesive capsulitis-hypothyroidism and diabetes. Logistic regression analysis was conducted controlling for factors including sex, thyroid dysfunction, diabetes, shoulder dislocation, smoking, and genetics.

RESULTS

Three loci of significance were identified: rs34315830 (in WNT7B; odds ratio [OR] = 1.28; 95% confidence interval [CI], 1.22 to 1.39), rs2965196 (in MAU2; OR = 1.67; 95% CI, 1.39 to 2.00), and rs1912256 (in POU1F1; OR = 1.22; 95% CI, 1.14 to 1.31). These loci retained significance when controlling for thyroid dysfunction and diabetes. The OR for total genetic risk was 5.81 (95% CI, 4.08 to 8.31), compared with 1.70 (95% CI, 1.18 to 2.36) for hypothyroidism and 4.23 (95% CI, 2.32 to 7.05) for diabetes.

CONCLUSIONS

The total genetic risk associated with adhesive capsulitis was significant and similar to the risks associated with hypothyroidism and diabetes. Identification of WNT7B, POU1F1, and MAU2 implicates the Wnt pathway and cell proliferation response in the pathomechanism of adhesive capsulitis.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Applying a genetic risk score for prostate cancer to men with lower urinary tract symptoms in primary care to predict prostate cancer diagnosis: a cohort study in the UK Biobank

BACKGROUND

Prostate cancer is highly heritable, with >250 common variants associated in genome-wide association studies. It commonly presents with non-specific lower urinary tract symptoms that are frequently associated with benign conditions.

METHODS

Cohort study using UK Biobank data linked to primary care records. Participants were men with a record showing a general practice consultation for a lower urinary tract symptom. The outcome measure was prostate cancer diagnosis within 2 years of consultation. The predictor was a genetic risk score of 269 genetic variants for prostate cancer.

RESULTS

A genetic risk score (GRS) is associated with prostate cancer in symptomatic men (OR per SD increase = 2.12 [1.86-2.41] P = 3.5e-30). An integrated risk model including age and GRS applied to symptomatic men predicted prostate cancer (AUC 0.768 [0.739-0.796]). Prostate cancer incidence was 8.1% (6.7-9.7) in the highest risk quintile. In the lowest quintile, prostate cancer incidence was <1%.

CONCLUSIONS

This study is the first to apply GRS in primary care to improve the triage of symptomatic patients. Men with the lowest genetic risk of developing prostate cancer could safely avoid invasive investigation, whilst those identified with the greatest risk could be fast-tracked for further investigation. These results show that a GRS has potential application to improve the diagnostic pathway of symptomatic patients in primary care.

A retrospective study of ultrasound-guided intervention for frozen shoulder in the frozen stage

Background

To investigate the clinical value of ultrasound (US)-guided intervention for frozen shoulder (FS) in the frozen stage.

Methods

This study included 40 patients who had primary FS in the frozen stage and were evaluated by US. These 40 patients have all received conservative treatment elsewhere, and no satisfactory results have been achieved, with no improvement in active and passive movement angles, and no improvement in scores within 3 months. Therefore, their previous treatment was set as comparison. All patients underwent US-guided shoulder joint capsule distension by injection of sterilized water. Of these participants, 22 patients with scapulohumeral periarthritis received a compound betamethasone injection, and 14 patients with thickened coracohumeral ligaments (CHLs) underwent acupotomy lysis, and the remaining 4 patients had no extra treatments. The Constant-Murley score (CMS) was evaluated before and after the operation and analysed for each patient.

Results

Before treatment, the indices for the thickening of the subaxillary joint capsule, subacromial bursa (with or without effusion), long head of the biceps brachii tendon (LHBBT) and CHL were 40, 22, 16 and 14, respectively. After treatment, all the indices were significantly decreased (all P < 0.010) except for that of the LHBBT (P = 0.123). The patients' CMSs improved, with the median total CMS increasing from 59 points (interquartile range: 53–64 points) to 86 points (interquartile range: 78–90 points) (P < 0.010). While the internal rotation (Ir) of the shoulder joint did not improve (FDRs < 0.50), abduction, forward flexion (Ff) and external rotation (Er) improved significantly (all FDRs = 1.00).

Conclusion

Compared with conservative treatment, US-guided intervention for FS in the frozen stage is highly effective and of great clinical value.

Frozen shoulder

Frozen shoulder is a common debilitating disorder characterized by shoulder pain and progressive loss of shoulder movement. Frozen shoulder is frequently associated with other systemic conditions or occurs following periods of immobilization, and has a protracted clinical course, which can be frustrating for patients as well as health-care professionals. Frozen shoulder is characterized by fibroproliferative tissue fibrosis, whereby fibroblasts, producing predominantly type I and type III collagen, transform into myofibroblasts (a smooth muscle phenotype), which is accompanied by inflammation, neoangiogenesis and neoinnervation, resulting in shoulder capsular fibrotic contractures and the associated clinical stiffness. Diagnosis is heavily based on physical examination and can be difficult depending on the stage of disease or if concomitant shoulder pathology is present. Management consists of physiotherapy, therapeutic modalities such as steroid injections, anti-inflammatory medications, hydrodilation and surgical interventions; however, their effectiveness remains unclear. Facilitating translational science should aid in development of novel therapies to improve outcomes among individuals with this debilitating condition.

Risk Factors for the Onset of Frozen Shoulder in Middle-Aged and Elderly Subjects Within 1 Year of Discharge From a Hospitalization That Involved Intravenous Infusion: A Prospective Cohort Study

AIM

To investigate the incidence of frozen shoulder and risk factors for the onset of frozen shoulder in middle-aged and elderly subjects within 1 year of discharge from a hospitalization that involved intravenous infusion in Zhangjiagang Second People's Hospital.

METHODS

A total of 1,900 subjects who were discharged from a hospitalization that involved intravenous infusion in the hospital between May 2020 and September 2020 met the inclusion criteria for this study: 950 subjects had a mean daily duration of intravenous infusion ≤ 2 h (low exposure) and 950 subjects had a mean daily duration of intravenous infusion ≥3 h (high exposure). Subjects were followed up by telephone at 6 months ± 1 week and 12 months ± 1 week after discharge the incidence of frozen shoulder.

RESULTS

The cumulative incidence rate of frozen shoulder within 1 year of discharge was 5.2%. Multivariate logistic regression analysis revealed the risk of frozen shoulder was higher in subjects with a mean daily duration of intravenous infusion ≥3 h compared to ≤ 2 h (OR = 3.082, 95% CI 1.919-4.949, P < 0.001); subjects hospitalized for 11-30 days had a higher risk of frozen shoulder compared to those hospitalized for 10 days or less (OR = 6.836, 95%CI 4.363-10.709, P < 0.001); subjects who were overweight/ obese (BMI ≥ 25 kg/m²) had a higher risk of frozen shoulder compared to those of normal weight (BMI 18.5-24.9 kg/m²) (OR = 2.166, 95%CI 1.376-3.410, P = 0.001); subjects in the 56-70-year-old age group had a higher risk of developing frozen shoulder compared to those in the 40-55-year-old age group (OR = 1.977, 95%CI 1.154-3.387, P = 0.013); diabetes increased the risk of frozen shoulder (OR = 3.009, 95%CI 1.826-4.959, P < 0.001). The 71-85 years old age group and hypertension were statistically significant in univariate analysis but not in multivariate analysis (P > 0.05).

CONCLUSION

Compared with middle-aged and elderly in the general population, middle-aged and elderly subjects who received intravenous infusion during a hospitalization had a higher cumulative incidence rate of frozen shoulder within 1 year after discharge. Independent risk factors for the onset of frozen shoulder included mean daily duration of intravenous infusion ≥3 h, length of hospital stay 11-30 days, BMI ≥ 25 kg/m², age 56-70 years, and diabetes.