Associations of Metabolic Syndrome and Its Components with the Risk of Incident Knee Osteoarthritis Leading to Hospitalization: A 32-Year Follow-up Study

Risk factors for the development of knee osteoarthritis across the lifespan: A systematic review and meta-analysis

OBJECTIVE

To identify and quantify risk factors for incident knee osteoarthritis (KOA) across the lifespan.

METHODS

This systematic review and meta-analysis identified eligible studies from seven electronic databases and three registries. Longitudinal cohort studies or randomised controlled trials evaluating participants who developed incident symptomatic and/or radiographic KOA were included. Two independent reviewers completed data screening and extraction. Estimates were pooled using a random effects model and reported as odds ratio (OR), hazard ratio, or risk ratio and corresponding 95% confidence intervals (95% CI). Grading of Recommendations, Assessment, Development and Evaluation was used to determine the certainty of evidence. Population attributable fractions were calculated, including risk factors significantly associated with radiographic KOA based on the pooled meta-analysis and where we could determine communality scores using existing clinical datasets.

RESULTS

We identified 131 studies evaluating > 150 risk factors. Previous knee injury, older age and high bone mineral density were associated with an increased risk of incident radiographic KOA based on the pooled analysis [OR (95% CI): 2.67 (1.41, 5.05), 1.15 (1.00, 1.33) and 1.82 (1.12, 2.94), respectively], with moderate-to-high certainty. Two risk factors (overweight/obesity and previous knee injury) accounted for 14% of incident radiographic KOA. Other modifiable risk factors, including occupational physical activity, also contribute to radiographic or symptomatic KOA.

CONCLUSION

Novel strategies addressing known modifiable risk factors including overweight/obesity, knee injuries and occupational physical activity are needed to reduce overall burden of KOA.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO ID: CRD42023391187.

Evaluation of the causal relationship between 28 circulating biomarkers and osteoarthritis : a bidirectional Mendelian randomization study

Aims

Circulating biochemistry markers are commonly used to monitor and detect disease-induced dysfunctions including osteoarthritis (OA). However, the causal nature of this relationship is nevertheless largely unknown, due to unmeasured confounding factors from observational studies. We aimed to reveal the causal relationship between 28 circulating biochemistry markers and OA pathogenesis.

Methods

We conducted a comprehensive bidirectional two-sample Mendelian randomization (MR) study between 28 circulating biomarkers and six OA types, using large-scale genome-wide association study (GWAS) summary statistics data from a UK Biobank cohort (n = 450,243) and the latest OA meta-analysis (n = 826,690). We replicated the significant results of low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) in an independent large GWAS dataset obtained from the Global Lipids Genetics Consortium (GLGC) (n > 800,000).

Results

Using 73 to 792 instrumental variables for biomarkers, this large MR analysis identified 11 causal associations at the Bonferroni corrected significance level of 2.98 × 10-4, involving seven biomarkers and five OA types. LDL-C (odds ratio (OR) per SD increase 0.90, 95% CI 0.86 to 0.93), apolipoprotein B (OR 0.86, 95% CI 0.82 to 0.91), TC (OR 0.90, 95% CI 0.86 to 0.94), calcium (OR 0.82, 95% CI 0.75 to 0.90), and glucose (OR 0.81, 95% CI 0.73 to 0.89) are causally associated with a reduced risk of OA, while phosphate (OR 1.18, 95% CI 1.08 to 1.30) and aspartate aminotransferase (OR 1.15, 95% CI 1.07 to 1.24) are causally associated with an increased risk. Analysis of GLGC summary statistics successfully replicated LDL-C (OR 0.93, 95% CI 0.90 to 0.96) and TC (OR 0.92, 95% CI 0.89 to 0.95).

Conclusion

This comprehensive bidirectional MR analysis provides new insights into the prevention and treatment of OA, as well as understanding the biological mechanism underlying OA pathogenesis.

Genetic proxies for therapy of insulin drug targets and risk of osteoarthritis: a drug-target Mendelian randomization analysis

BACKGROUND

The potential effects of insulin therapy on osteoarthritis (OA) risk are poorly understood. This study aimed to explore the causal relationship between insulin therapy and OA.

METHODS

Mendelian randomization (MR) analysis was performed to examine the association between genetically proxied inhibition of insulin targets and the risk of overall, hip (HOA) and knee OA (KOA). We then performed univariable MR using summary statistics regarding insulin target genes derived from the DrugBank database. Data related to blood glucose reduction levels were used as a proxy for insulin levels. Two phenotypes, type 2 diabetes, and glycosylated hemoglobin levels, were selected as positive controls to confirm the direction and validity of the proxies. The OA datasets were derived from the UK Biobank cohort. Multivariable MR was adjusted for body mass index, sedentary behavior, cigarette smoking, frequency of alcohol intake, age, and genetic sex.

RESULTS

Genetically proxied insulin therapy was associated with an increased risk of overall OA [odds ratio (OR):1.2595; 95% confidence interval (CI):1.0810-1.4675] and HOA (OR:1.4218; 95%CI:1.1240-1.7985), which remained consistent across multiple MR methods. After adjusting for confounders, we found evidence supporting a significant causal link with a higher risk of overall OA and HOA. A further two-step MR analysis revealed no significant mediation effects from the six mediators in the associations.

CONCLUSION

There was a causal association between genetically proxied insulin therapy and a higher risk of OA, especially HOA.

Is there a genetic relationship between blood glucose and osteoarthritis? A mendelian randomization study

OBJECTIVE

The relationship between blood glucose levels and osteoarthritis (OA) is unclear. This study aimed to investigate the genetic causal relationship between blood glucose-related traits and OA.

METHODS

We first performed univariate Mendelian randomization (UVMR) analyses using published genome-wide association study (GWAS) datasets with fasting glucose (FG), 2 h-glucose post-challenge glucose (2hGlu), and glycosylated hemoglobin (HbA1c) as exposures, and hip osteoarthritis (HOA) and knee osteoarthritis (KOA) as outcomes; then, we performed inverse analyses of them. We used Inverse-variance weighted (IVW) analysis as the primary analysis, and sensitivity analyses were performed. Moreover, we performed multivariate Mendelian randomization (MVMR) to estimate the independent effect of exposure on outcome after adjusting for body mass index (BMI). Summarized data for blood glucose-related traits were obtained from the MAGIC Consortium study of the glucose trait genome and for OA from the UK Biobank and arcOGEN. Summarized data for BMI were obtained from the GIANT Consortium meta-analysis of individuals of European ancestry. A two-sided p value < 0.05 in UVMR was considered suggestive of significance when p < 0.0167 (Bonferroni correction p = 0.05/3 exposures) was considered statistically significant.

RESULTS

We found significant negative genetic causality of FG for HOA and KOA, and these associations remained significant after we adjusted for the effect of BMI [odds ratios (ORs) of 0.829 (0.687-0.999, p = 0.049) and 0.741 (0.570-0.964, p = 0.025)]. HbA1c also had an independent negative genetic causal effect on HOA after adjustment for BMI [0.665 (0.463-0.954, p = 0.027)]. At the same time, there was no evidence of reverse genetic causality of OA on blood glucose-related traits.

CONCLUSION

We further elucidated the relationship between blood glucose-related traits and OA by adjusting for the effect of BMI from a genetic causal perspective. This study provides new insights to further clarify the relationship between blood glucose levels and OA, as well as the pathogenesis, etiology and genetics of OA.

Causal link between metabolic related factors and osteoarthritis: a Mendelian randomization investigation

Introduction

Metabolic syndrome (MetS) is significantly associated with osteoarthritis (OA), especially in MetS patients with blood glucose abnormalities, such as elevated fasting blood glucose (FG), which may increase OA risk. Dietary modifications, especially the intake of polyunsaturated fatty acids (PUFAs), are regarded as a potential means of preventing MetS and its complications. However, regarding the effects of FG, Omega-3s, and Omega-6s on OA, the research conclusions are conflicting, which is attributed to the complexity of the pathogenesis of OA. Therefore, it is imperative to thoroughly evaluate multiple factors to fully understand their role in OA, which needs further exploration and clarification.

Methods

Two-sample univariable Mendelian randomization (UVMR) and multivariable Mendelian randomization (MVMR) were employed to examine the causal effect of metabolic related factors on hip OA (HOA) or knee OA (KOA). The exposure and outcome datasets were obtained from Open GWAS IEU. All cases were independent European ancestry data. Three MR methods were performed to estimate the causal effect: inverse-variance weighting (IVW), weighted median method (WMM), and MR-Egger regression. Additionally, the intercept analysis in MR-Egger regression is used to estimate pleiotropy, and the IVW method and MR-Egger regression are used to test the heterogeneity.

Results

The UVMR analysis revealed a causal relationship between FG and HOA. By MVMR analysis, the study discovered a significant link between FG (OR = 0.79, 95%CI: 0.64∼0.99, p = 0.036) and KOA after accounting for body mass index (BMI), age, and sex hormone-binding globulin (SHBG). However, no causal effects of FG on HOA were seen. Omega-3s and Omega-6s did not have a causal influence on HOA or KOA. No significant evidence of pleiotropy was identified.

Discussion

The MR investigation showed a protective effect of FG on KOA development but no causal relationship between FG and HOA. No causal effect of Omega-3s and Omega-6s on HOA and KOA was observed. Shared genetic overlaps might also exist between BMI and age, SHBG and PUFAs for OA development. This finding offers a novel insight into the treatment and prevention of KOA from glucose metabolism perspective. The FG cutoff value should be explored in the future, and consideration should be given to demonstrating the study in populations other than Europeans.

Evidence on risk factors for knee osteoarthritis in middle-older aged: a systematic review and meta analysis

PURPOSE

This review was made to identify the risk factors for knee osteoarthritis (KOA) in middle-older aged (≥ 40 years), and to provide the newest evidence for the prevention of KOA.

METHOD

Cohort study and case-control study of the risk factors of KOA was included from Pubmed, Web of Science, Ovid Technologies, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP), Wanfang Database, SinoMed from their inceptions to July 2023. Two authors independently screened the literature and extracted data. Assessment of quality was implemented according to Agency for Healthcare Research and Quality (AHRQ) and Newcastle-Ottawa Quality Assessment Scale. Meta-analysis was performed using RevMan 5.3 software.

RESULTS

3597 papers were identified from the seven databases and 29 papers containing 60,354 participants were included in this review. Meta-analysis was performed for 14 risk factors, and 7 of these were statistical significance (P < 0.05). The risk factors which were analyzed in this review included trauma history in knee (1.37 [95% CI 1.03-1.82], P = 0.030), body mass index (BMI) ≥ 24 kg/m2 (1.30 [95% CI 1.09-1.56], P = 0.004), gender (female) (1.04 [95% CI 1.00-1.09], P = 0.030), age ≥ 40 (1.02 [95% CI 1.01-1.03], P = 0.007), more exercise (0.75 [95% CI 0.62-0.91], P = 0.003), a high school education background (0.49 [95% CI 0.30-0.79], P = 0.003) and an university education background (0.22 [95% CI 0.06-0.86], P = 0.030).

CONCLUSION

The risk factors analyzed in this review included trauma history in knee, overweight or obesity, gender (female), age ≥ 40 and the protective factors included more exercise and a high school or an university education background.

Metabolic syndrome and the likelihood of knee pain and functional disability: evidence from a large middle eastern population-based study

OBJECTIVES

Metabolic Syndrome (MetS) has been associated with knee osteoarthritis (KOA) in animal studies, but epidemiologic evidence of the association remains controversial. We investigated the association between MetS and knee pain and functional disability, the hallmarks of KOA, in a Middle Eastern population with high reported MetS rates.

METHODS

A population-based study of adult individuals was conducted between 01/2016 and 03/2019. Data collected included age, sex, blood pressure, body mass index (BMI), waist circumference (WC), and comprehensive metabolic panel blood tests. Knee symptoms were assessed using The Western Ontario and McMaster Arthritis index (WOMAC) The Adult Treatment Panel III criteria was applied to determine if participants had MetS. Multivariable regression was used to determine the association of MetS, and its components, with the WOMAC total and subscale scores.

RESULTS

Of 6,000 participants enrolled, 15.5% had MetS. The multivariate regression demonstrated that participants with MetS had significantly higher WOMAC total and subscale scores after adjusting for demographic variables; however, these associations were not significant after adjusting for BMI. Multivariate regression examining the association between MetS components and the WOMAC scores showed sex-based significant differences with WOMAC scores; however, the differences were not larger than the minimally clinical important differences.

CONCLUSIONS

This study demonstrated that after adjustment for BMI, neither MetS nor its individual parameters were associated with worse knee symptoms. As such, the association between MetS and worse knee symptoms requires further study.

Metformin use and associated risk of total joint replacement in patients with type 2 diabetes: a population-based matched cohort study

BACKGROUND

It is uncertain whether metformin use is associated with reduced risk of joint replacement in patients with type 2 diabetes mellitus. We aimed to establish whether metformin use was associated with a reduced risk of total knee replacement (TKR) or total hip replacement (THR) among these patients.

METHODS

We selected patients with type 2 diabetes mellitus that was diagnosed between 2000 and 2012 from the Taiwan National Health Insurance Research Database. We used prescription time-distribution matching and propensity-score matching to balance potential confounders between metformin users and nonusers. We assessed the risks of TKR or THR using Cox proportional hazards regression.

RESULTS

We included 20 347 participants who were not treated with metformin and 20 347 who were treated with metformin, for a total of 40 694 participants (mean age 63 yr, standard deviation 11 yr; 49.8% were women) after prescription time-distribution matching. Compared with participants who did not use metformin, those who used metformin had lower risks of TKR or THR (adjusted hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.60-0.81 for TKR or THR; adjusted HR 0.71, 95% CI 0.61-0.84 for TKR; adjusted HR 0.61, 95% CI 0.41-0.92 for THR) after adjustment for covariates. Propensity-score matching analyses (10 163 participants not treated with metformin v. 10 163 treated with metformin) and sensitivity analyses using inverse probability of treatment weighting and competing risk regression showed similar results.

INTERPRETATION

Metformin use in patients with type 2 diabetes mellitus was associated with a significantly reduced risk of total joint replacement. Randomized controlled clinical trials in patients with osteoarthritis are warranted to determine whether metformin is effective in decreasing the need for joint replacement.

Development and Validation of a Novel Nomogram to Predict the Risk of Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) has been a complex disorder resulted from genetic and environmental risk factors. The aim of this study was to identify the risk factors associated with IVDD in orthopaedic patients and develop a prediction model for predicting the risk of IVDD. A total of 309 patients were retrospectively included in the study and randomly divided into the training group and the validation group. The least absolute shrinkage and selection operator regression (LASSO) and the univariate logistic regression analysis were used to optimize factors selection for the IVDD risk model. Multivariable logistic regression analysis was used to establish a predicting nomogram model incorporating the factors. In addition, discrimination, calibration, and clinical usefulness of the nomogram model were evaluated via the C-index, receiver operating characteristic (ROC) curve, calibration plot, and decision curve analysis (DCA). Then, based on the results above, the relationship between IVDD and angiotensin II (AngII) level in peripheral blood was examined prospectively. The predictors of the nomogram include age, sex, hypertension, diabetes, gout, working posture, and exercising hours per week. The C-index values of the training and validation groups were 0.916 (95% CI, 0.876-0.956) and 0.949 (95% CI, 0.909-0.989), respectively, which indicated that the model displayed good discrimination. In addition, the area under the curve (AUC) values of the ROC curve of the training and the validation group were 0.815 (95% CI, 0.759-0.870) and 0.805 (95% CI, 0.718-0.892), respectively, revealing the satisfactory discrimination performance of the model. The prospective investigation showed that the average AngII level in the degenerated group (97.62 ± 44.02 pg/mL) was significantly higher than that in the nondegenerated group (52.91 ± 9.01 pg/mL) (p < 0.001). This present study explored the risk factors for IVDD and established a prediction model, which would effectively predict the risk of IVDD. In addition, based on the prediction model, AngII was revealed to be a potentially auxiliary clinical diagnostic marker for IVDD.

Metabolic syndrome and the incidence of knee osteoarthritis: A meta-analysis of prospective cohort studies

Background

Cross-sectional studies suggest an association between metabolic syndrome (MetS) and knee osteoarthritis (KOA). We performed a meta-analysis to evaluate whether MetS is an independent risk factor for KOA.

Methods

Prospective cohort studies evaluating the association between MetS and KOA in general population were retrieved from PubMed and Embase. Only studies with multivariate analyses were included. Data were pooled with a random-effect model, which is considered to incorporate heterogeneity among the included studies.

Results

Five studies including 94,965 participants were included, with 18,990 people with MetS (20.0%). With a mean follow-up duration of 14.5 years, 2,447 KOA cases occurred. Pooled results showed that MetS was not significant associated with an increased risk of KOA after controlling of factors including body mass index (adjusted risk ratio [RR]: 1.06, 95% CI: 0.92~1.23, p = 0.40; I² = 33%). Subgroup analysis showed that MetS was independently associated with an increased risk of severe KOA that needed total knee arthroplasty (RR = 1.16, 95% CI: 1.03~1.30, p = 0.02), but not total symptomatic KOA (RR = 0.84, 95% CI: 0.65~1.08, p = 0.18). Stratified analyses suggested that MetS was independently associated with an increased risk of KOA in women (RR = 1.23, 95% CI: 1.03~1.47, p = 0.02), but not in men (RR = 0.90, 95% CI: 0.70~1.14, p = 0.37).

Conclusions

Current evidence from prospective cohort studies did not support MetS was an independent risk factor of overall KOA in general population. However, MetS may be associated with an increased risk of severe KOA in general population, or overall KOA risk in women.