Impact of parity on pelvic floor morphology and function: A retrospective study.

To analyze the effect of parity on pelvic floor morphology and function during the postpartum period. A total of 971 participants, who attended the Fujian Maternity and Child Health Hospital (Fuzhou, China) between December 2019 and August 2021, were included. All participants were assessed using the modified Oxford scale (MOS), pelvic floor surface electromyography, and 3-dimensional pelvic floor ultrasound to assess pelvic floor morphology and function. Multivariate analysis revealed no differences among primipara, deuteripara, and tertipara in pre-baseline rest, phasic contraction, endurance contraction, post-baseline rest, and MOS, except for tonic contraction (P = .020), the amplitude of which was lower in primipara than in deuteripara in post hoc comparison (P = .008). Differences in bladder neck presentation and bladder neck descent were statistically significant in multivariate analysis (P = .002, P = .001, respectively), with the value of bladder neck presentation in primiparas being greater than that of deuteriparas and tertipara (P = .002, P = .008, respectively), and the value of bladder neck descent was lower than that of deuteripara and tertipara in further post hoc comparisons (P = .002, P = .003, respectively). Functional impairment was not statistically associated with parity according to the MOS score or surface electromyography. However, parity was significantly correlated with descent of the bladder neck, and most of the effects appeared to occur during the first delivery.

A scientometrics analysis and visualisation of diabetic foot research from 1955 to 2022.

Diabetic foot (DF) has become a serious health problem in modern society, and it has been a hotspot of research for a long time. However, little scientometric analysis has been carried out on DF. In the present study, we analysed 8633 literature reports on DF in the Web of Science Core Collection from database inception until April 23, 2022. VOSviewer (Centre for Science and Technology Studies at Leiden University, Leiden, the Netherlands) and CiteSpace (College of Computing and Informatics, Drexel University, Philadelphia, United States) were employed to address high-impact countries and institutions, journals, references, research hotspots, and key research fields in DF research. Our analysis findings indicated that publications on DF have increased markedly since 2016 and were primarily published in the United States of America. The recent studies focus on the amniotic membrane, foot ulcers, osteomyelitis, and diabetic wound healing. The five keyword clusters, which included DF ulcer and wound healing therapies, management and guidelines, neuropathy and plantar pressure, amputation and ischemia, and DF infection and osteomyelitis, are helpful for enhancing prevention, standardising treatment, avoiding complications, and improving prognosis. These findings indicated a method for future therapies and research in DF.

TYRO protein tyrosine kinase-binding protein predicts favorable overall survival in osteosarcoma and correlates with antitumor immunity.

To explore the prognostic significance and underlying mechanism of TYRO protein tyrosine kinase-binding protein (TYROBP) in osteosarcoma. Firstly, the expression of TYROBP was analyzed using the t test. The Kaplan-Meier plotter analysis and a receiver operating characteristic curve were performed to evaluate the influence of TYROBP on overall survival (OS). Further, Cox regression analysis was conducted to predict the independent prognostic factors for OS of osteosarcoma patients, and a nomogram was constructed. Then, the relationship between TYROBP and clinicopathological characteristics was determined using statistical methods. Enrichment analyses were conducted to evaluate the biological functions of TYROBP. Finally, the ESTIMATE algorithm was used to assess the association of TYROBP with immune cell infiltration. TYROBP was significantly increased in osteosarcoma (all P < .001). However, the high expression of TYROBP was related to better OS in osteosarcoma patients. Cox regression analysis showed that TYROBP was an independent prognostic factor for predicting OS (P = .005), especially in patients of the male sex, age <18 years, metastasis, and tumor site leg/foot (all P < .05). Besides, TYROBP mRNA expression was significantly associated with the tumor site (P < .01) but had no remarkable relationship with age, gender, and metastasis status (all P > .05). Functional annotation and gene set enrichment analysis (GSEA) revealed that TYROBP was mainly involved in immune-related pathways. Importantly, TYROBP positively correlated with immune scores (P < .001, R = .87). TYROBP served as an independent prognostic biomarker for OS in osteosarcoma. High TYROBP expression might prolong the survival of osteosarcoma patients mainly through promoting antitumor immunity.

Sperm parameters and anti-Müllerian hormone remain stable with Helicobacter pylori infection: a cross-sectional study.

BACKGROUND AND AIMS: It has been reported that Helicobacter pylori (HP) infection was more prevalent in infertile populations. HP infection could lead to decreased sperm parameters, and treating the HP infection could improve the quality of sperm. However, studies investigating the relationship between infertility and HP infection are still limited, and more evidence is required. Therefore, we performed the present study to investigate the impact of HP infection on sperm quality in males and on ovarian reserve in females. METHODS: A total of 16,522 patients who visited the Second Hospital of Zhejiang University from January 2016 to June 2019 due to abdominal discomfort and underwent a 13/14C-urea breath HP test were included in this retrospective cross-sectional study. Among them, 565 had performed sperm analysis or ovarian reserve tests in the past three months and were involved for further analyses. Sperm parameters were examined with a computer-assisted sperm analysis system, and serum anti-Müllerian hormone (AMH) and sex hormones were tested with an electrochemiluminescence method. RESULTS: Among 363 patients who underwent the sperm test, 136 (37.47%) had HP infection. Among 202 patients who underwent the AMH test, 55 (27.23%) had HP infection. There was no difference in sperm concentration and motility between the HP+ and HP- groups (P > 0.05). Further subgroup analyses stratified into 5-year age groups confirmed that there was no significant difference in sperm parameters (P > 0.05). When pooled with previously published data, no significant difference in sperm concentration or motility was found (P > 0.05). Meanwhile, this study found that the serum AMH level was similar between the HP+ and HP- groups (P > 0.05). Further subgroup analyses confirmed that there was no significant difference in serum AMH level (P > 0.05). CONCLUSIONS: There were no differences in sperm parameters and AMH levels based on history of HP infection among Chinese patients.

Role of anti-Müllerian hormone and testosterone in follicular growth: a cross-sectional study.

BACKGROUND: Anti-Müllerian hormone (AMH) is now considered the best serum biomarker of ovarian reserve, while basal sex hormones are classic markers used for assessing ovarian reserve. The interaction between AMH and sex hormones are complicated and not sufficiently addressed. In this study, we took diminished ovarian reserve (DOR) and polycystic ovarian syndrome (PCOS) as two extremes of ovarian reserve (deficient and excessive respectively) to investigate the role of AMH and sex hormones in follicular growth. METHODS: A retrospective cross-sectional survey was performed. The patients assessed AMH and basal sex hormones in the Second Hospital of Zhejiang University from April 2016 to March 2019 were involved in this study. Serum AMH and sex hormone concentrations were tested with electrochemiluminescence method. Stepwise linear regression and binary logistic regression was used to determine the predictors of AMH level and to explore the involved factors determining DOR and PCOS. RESULTS: In the present study, we found that age and follicle-stimulating hormone (FSH) were main negative correlation factors, and luteinizing hormone (LH) and testosterone (T) were main positive factors of AMH. In DOR group, age, FSH and estradiol (E2) increased and T decreased, while in PCOS group, LH and T increased. Binary logistic regression found that age, weight, FSH, E2, and T were the significant factors which independently predicted the likelihood of DOR, and that age, body mass index (BMI), AMH, LH, and T predicted the likelihood of PCOS. CONCLUSIONS: Our study demonstrated that age, FSH, and T were factors that most closely correlated with AMH level, and T was involved in both DOR and PCOS. Since DOR and PCOS are manifested with insufficient AMH and excessive AMH respectively, it is suggested that total testosterone correlated with AMH closely and plays an important role in follicular growth. More attention should be given to testosterone level during controlled ovarian hyperstimulation (COH) process.

Overproduced bone marrow neutrophils in collagen-induced arthritis are primed for NETosis: An ignored pathological cell involving inflammatory arthritis.

OBJECTIVES: Bone marrow edema is a universal manifestation of rheumatoid arthritis (RA), and its pathological essence is a bone marrow lesion (BML) formed by various bone marrow (BM) immune cells. Neutrophils play an important role in inflammatory arthritis, but the role and mechanism of neutrophils in BML are not clear. MATERIALS AND METHODS: Granulocyte colony-stimulating factor (G-CSF) -/- mice and wild type (WT) C57BL/6 mice were immunized for collagen-induced arthritis (CIA). Histological scores of arthritis were evaluated. Immunohistochemistry staining with anti-Ly6G was conducted. Neutrophil extracellular traps (NETs) in joint sections were determined by immunofluorescence staining. BM neutrophils were isolated for flow cytometry and NETosis induction in vitro. RESULTS: Histological study showed significant neutrophil infiltrations in BML of CIA mice. Inhibition of BM neutrophil production by G-CSF knock out can obstruct the induction of BML and CIA. In addition to abundant infiltrated NETs intra-articular, remarkable NETosis primed BM neutrophils were infiltrated in BML of CIA mice, which was positively related to bone erosion. Neutrophils derived from G-CSF-/- mice have diminished ability of NETs formation in vitro, while G-CSF induction can enhance its capacity of NETs formation. CONCLUSIONS: We propose for the first time that the overproduced BM neutrophils in CIA mice are primed for NETosis in a G-CSF dependent manner, and these pathogenic cells may have an important role in inflammatory arthritis. Blocking this pathological process could be a potential strategy for the treatment of RA.

A Modified 2-Stage Treatment for AO/OTA 43-C1 Pilon Fractures Accompanied by Distal Fibular and Posterior Lip of the Distal Tibia Fracture.

The management of pilon fractures remains challenging owing to the high-energy axial loading mechanism that produces comminution of the articular surface, displacement of tibia metaphysis, and severe soft tissue injury. How to preserve the vitality of soft tissue and achieve anatomic reduction has become a timely issue. We report and evaluate the effect of a modified staging treatment for AO Foundation/Orthopaedic Trauma Association (AO/OTA) 43C1 pilon fracture accompanied by distal fibular and posterior lip of the distal tibia fracture. We performed a modified 2-stage treatment of type C1 pilon fracture with distal fibular and posterior malleolar fractures. In the first stage, the posterolateral incision was used for simultaneous reduction of fibula and posterior malleolus, and the tibia was fixed with an external fixator. In the second stage, the external fixator was removed, and the medial malleolus and tibia were fixed after the edema of soft tissue had subsided. The following data were collected: Foot and Ankle Outcome Score (FAOS), American Orthopaedic Foot & Ankle Society (AOFAS) score, Short Form 36 (SF-36) score, Burwell-Charnley fracture reduction score, and postoperative complications. Twenty-seven patients were monitored for an average of 31.70 ± 7.38 months. The Burwell-Charnley fracture reduction scores had anatomic and fair ratings of 92.59%. SF-36 physical component score was 42.94 ± 12.47 and mental component score was 48.73 ± 9.79. Score data from the multiple scales of FAOS included pain, 88.79 ± 8.59; activities of daily living, 91.89 ± 7.50; quality of life, 90.26 ± 10.52; sports, 87.93 ± 11.64; and symptoms, 85.32 ± 8.65. The AOFAS ankle-hindfoot scores were 87.30 ± 13.45. Complications were reported in 5 patients (18.52%). Our study provides a good alternative to the existing protocol for type C1 pilon fractures with distal fibular and posterior lip of the distal tibia fracture and effectively reduces soft tissue complications.

Circulating microRNA let­7e is decreased in knee osteoarthritis, accompanied by elevated apoptosis and reduced autophagy.

Knee osteoarthritis (KOA) is a major cause of leg disability in the elderly population. Recently, the expression levels of circulating microRNA (miRNA) let­7e have been reported to be significantly reduced in KOA. The aims of the present study were to assess the feasibility of let­7e as a serum marker for detecting KOA and to explore the underlying mechanisms of its involvement. Based on previous studies and bioinformatics analysis, let­7e may regulate apoptosis and autophagy of articular chondrocytes. A total of 10 patients with KOA and 10 patients with trauma without KOA were recruited to examine the levels of let­7e in peripheral blood. Subsequently, KOA rat models were established, and the levels of let­7e in the cartilage and serum were examined, the expression of apoptotic proteins and autophagy­related proteins in the cartilage were investigated, and apoptotic and autophagic activities of primary cultured chondrocytes were also detected. In patients with KOA, let­7e levels in the peripheral serum were significantly decreased compared with the control group, and this result was confirmed in the peripheral serum and cartilage of KOA rats. In addition, the expression levels of proteins involved in the apoptotic pathway were increased in the cartilage of KOA rats, and apoptotic activity was increased. The expression of autophagy­related proteins beclin 1 and microtubule associated protein 1 light chain 3 ß (LC3B) II/LC3BI in the articular cartilage of KOA rats was lower compared with the controls, and autophagy was decreased. Si­Miao­San (SMS) treatment restored the expression of let­7e and reversed the changes in apoptosis and autophagy. Therefore, the present study provided additional evidence that circulating let­7e may be a potential serum biomarker for the diagnosis and treatment of KOA. Elevated apoptosis levels and decreased autophagy levels of cartilage tissue are involved in KOA, and treatment with SMS may reverse these effects.

Construction of implantation failure related lncRNA-mRNA network and identification of lncRNA biomarkers for predicting endometrial receptivity.

Insufficient endometrial receptivity is a major factor leading to implantation failure (IF), and the traditional way of morphological observation of endometrium cannot determine the condition of receptivity sufficiently. Considering that long-noncoding RNAs (lncRNAs) regulate endometrial receptivity and competing endogenous RNA (ceRNA) mechanism works in plenty of biological processes, ceRNA is likely to function in the pathology of IF. In the present study, we aim to construct an implantation failure related lncRNA-mRNA network (IFLMN), and to identify the key lncRNAs as the candidates for predicting endometrial receptivity. The global background network was constructed based on the presumed lncRNA-miRNA and miRNA-mRNA pairs obtained from lncRNASNP and miRTarBase. Differentially expressed genes (DEGs) of IF were calculated using the data of GSE26787, and then re-annotated as differentially expressed mRNAs (DEMs) and lncRNAs (DELs). IFLMN was constructed by hypergeometric test, including 255 lncRNA-mRNA pairs, 10 lncRNAs, and 212 mRNAs. Topological analysis determined the key lncRNAs with the highest centroid. Functional enrichment analyses were performed by unsupervised clustering, GO classification, KEGG pathway, and co-expression module analyses, achieving six key lncRNAs and their ceRNA sub-networks, which were involved in immunological activity, growth factor binding, vascular proliferation, apoptosis, and steroid biosynthesis in uterus and prepared endometrium for embryo implantation. Sixteen endometrial samples were collected during mid-luteal phase, including 8 recurrent implantation failure (RIF) or recurrent miscarriage (RM) women and 8 controls who conceived successfully. Quantitative real-time PCR was performed to compare the expression of the above six lncRNAs, which validated that the expression of all these lncRNAs was significantly elevated in endometrium of RIF/RM patients. Further studies are needed to investigate the underlying mechanism, and the lncRNAs may be developed into predictive biomarkers for endometrial receptivity.

The risk factors of vertebral refracture after kyphoplasty in patients with osteoporotic vertebral compression fractures: a study protocol for a prospective cohort study.

BACKGROUND: Percutaneous kyphoplasty (PKP) is the first-line treatment for osteoporotic vertebral compression fractures (OVCFs) that can immediately relieve pain and allow the quick recovery of lost mobility. However, some studies reported that after PKP, the incidence of vertebral refracture, particularly adjacent vertebral fracture (AVF), was high. Our previous meta-analysis suggested that the risks for vertebral refracture and AVF did not increase after percutaneous vertebral augmentation in OVCF patients. Despite the negative results of our meta-analysis, there is still significant evidence regarding the relationship between kyphoplasty and AVF, so a new prospective cohort study is warranted. In addition, in our previous retrospective study, we found that advanced age, female sex and low oestradiol (E2) concentrations might be related to the occurrence of postoperative vertebral refracture after PKP. To sufficiently evaluate the probable factors involved in the occurrence of postoperative vertebral refracture, we designed this prospective study. METHODS: This is a prospective cohort study of patients admitted for PKP to treat painful OVCFs. The baseline data, including demographic information, lifestyle, bone metabolic status, sex hormone and sex hormone-binding globulin (SHBG) levels, and clinical characteristics will be collected at the time of enrolment. Surgical features of PKP will be recorded on the operation day. Lifestyle, bone metabolic status, sex hormone levels, and SHBG levels will be assessed during the follow-up period at 1 m, 3 m, 12 m, and 24 m postoperatively. Patients suffering from acutely aggravated back pain will be referred to an orthopaedist, and refractured vertebrae will be confirmed by magnetic resonance imaging and computed tomography. The primary outcome will be the incidence of vertebral refracture. Multivariate analyses will be carried out to evaluate the variables that are independently correlated with vertebral refracture. DISCUSSION: To evaluate the risk of postoperative refracture preoperatively and to identify the surgical points related to postoperative refracture, this study will explore the risk factors related to vertebral refracture after PKP. The results may provide new information about defining OVCF patients suitable for PKP treatment. TRIAL REGISTRATION: ChiCTR-ROC-17011562 . Registered on July 4th, 2017.

Association between tumor necrosis factor alpha rs1800629 polymorphism and risk of osteoarthritis in a Chinese population.

Osteoarthritis (OA) is the most common degenerative disease affecting articular cartilage. Some studies indicate that tumor necrosis factor alpha (TNF-α) gene rs1800629 polymorphism was associated with OA risk among Caucasian populations. To examine the role of this candidate gene in Asian populations, we conducted a hospital-based case-control study involving 257 knee OA patients and 305 controls in a Chinese population. Genotyping was performed using a custom-by-design 48-Plex single nucleotide polymorphism (SNP) Scan™ kit. Our study indicated that the AA genotype of TNF-α rs1800629 polymorphism was associated with increased risk of OA. Subsequently, we conducted a meta-analysis and found that rs1800629 polymorphism increased the risk of OA in the recessive and homozygous models. Stratification analysis of ethnicity also obtained a significant association among Asian populations. In conclusion, TNF-α rs1800629 polymorphism confers susceptibility to OA, especially among Asians. Larger studies with more diverse ethnic populations are needed to confirm these results.

Association between tumor necrosis factor alpha rs1800629 polymorphism and risk of osteoarthritis in a Chinese population

Osteoarthritis (OA) is the most common degenerative disease affecting articular cartilage. Some studies indicate that tumor necrosis factor alpha (TNF-α) gene rs1800629 polymorphism was associated with OA risk among Caucasian populations. To examine the role of this candidate gene in Asian populations, we conducted a hospital-based case-control study involving 257 knee OA patients and 305 controls in a Chinese population. Genotyping was performed using a custom-by-design 48-Plex single nucleotide polymorphism (SNP) Scan™ kit. Our study indicated that the AA genotype of TNF-α rs1800629 polymorphism was associated with increased risk of OA. Subsequently, we conducted a meta-analysis and found that rs1800629 polymorphism increased the risk of OA in the recessive and homozygous models. Stratification analysis of ethnicity also obtained a significant association among Asian populations. In conclusion, TNF-α rs1800629 polymorphism confers susceptibility to OA, especially among Asians. Larger studies with more diverse ethnic populations are needed to confirm these results.

Comparison of radiofrequency kyphoplasty (RFK) and balloon kyphoplasty (BKP) in the treatment of vertebral compression fractures: A meta-analysis.

BACKGROUND: Balloon kyphoplasty (BKP) is a widely adopted minimally invasive treatment for vertebral compression fractures (VCFs), but leakage of cement is a main complication of BKP. A novel vertebral augmentation technique radiofrequency kyphoplasty (RFK) with high viscosity cement was developed in 2009. Here, we aim to evaluate whether RFK can relieve symptoms efficiently and reduce cement leakage. METHODS: A literature search was performed using Pubmed, Embase, and Cochrane CENTRAL until September 30, 2016. Both randomized controlled trial (RCT) and non-RCT studies comparing RFK and BKP were included. The main outcomes included pain relief (VAS), functionality improvement (ODI), operation time, reduction of deformity (vertebral height and kyphosis angle), and incidence of cement leakage. The origin of heterogeneity was further explored by subgroup stratification. RESULTS: A total of 6 studies involving 833 patients with VCFs were included. The reduction of VAS score in the RFK group was 3.96 points more than that in the BKP group (P  =  .0007) postoperatively, and the improvement persisted until 12 months after the surgery (P < .00001). The operation time was shorter in RFK group than that in BKP group (P  =  .01). The increase of anterior vertebral height shortly after the operation was 0.53 mm greater in RFK group (P  =  .01). The decrease of kyphotic angle after RFK was 0.63° and 0.92° greater than that after BKP, both immediately and 6 months after operation (P  =  .002 and P < .00001, respectively). There was no significant difference between the incidence of cement leakage after RFK and BKP (P  =  .06). Further subgroup analysis stratified by study design indicated that the incidence of leakage decreased 15% in RFK than BPK (P < .00001) in non-RCT subgroup, but RFK and BKP treatments were equivalent in the RCT studies (P  =  .86). CONCLUSION: RFK appears to be more effective and safer than BKP in the present meta-analysis. The incidence of cement leakage diverges in RCT and non-RCT studies, so large-sample multicentered RCT studies are required to validate this new surgery system.

IGFBP1 Involved in the Decreased Birth Weight Due to Fetal High Estrogen Exposure in Mice.

Our previous study indicated that maternal high-estrogen environment in the first trimester is correlated with increased risks of low birth weight (LBW) and adult diseases. The present study aimed to establish an animal model to confirm such an effect in mice, and to further explore the mechanism involved. A mouse model with high estradiol (E2) exposure during early pregnancy was established, and the birth weight, growth after birth, and expression levels of insulin-like growth factor-binding protein 1 (IGFBP1) of pups were examined. Meanwhile, IGFBP1 expression after treatment of E2 was examined in a HepG2 hepatoma cell line. We found that after exposure to a high-E2 environment the weight of the pups decreased significantly, not only before but also after birth. Meanwhile, both mRNA and protein expressions of IGFBP1 were elevated in placenta and liver tissues. Furthermore, the level of IGFBP1 in the HepG2 cell line was elevated by the treatment of E2, whereas this effect was blocked by estrogen receptor antagonist ICI 182780. In summary, maternal high estrogen up-regulates expression of IGFBP1 in placenta and fetal livers, which contributes to LBW and decreases body weight in offspring.

The association between polymorphism of INSR and polycystic ovary syndrome: a meta-analysis.

Polycystic ovary syndrome (PCOS) is the most common gynecological endocrine disorder. The genetic background is believed to play a crucial role in the pathogenesis of PCOS. In recent years, the role of insulin receptor (INSR) polymorphisms in PCOS predisposition has attracted much attention. We performed a meta-analysis to investigate the association between the single nucleotide polymorphisms (SNPs) of INSR and PCOS. Published literature from Pubmed, Embase, and Cochrane CENTRAL was retrieved up until 7 August 2014. A total of 20 case-control studies including 23,845 controls and 17,460 PCOS cases with an average Newcastle-Ottawa quality assessment scale (NOS) score of 6.75 were analyzed. Ninety-eight SNPs distributed in 23 exons and the flanking regions of INSR were investigated, among which 17 SNPs were found to be associated with PCOS. Three SNPs detected in more than three studies were selected for further analyses. Twelve studies including 1158 controls and 1264 PCOS cases entered the analysis of rs1799817, but no significant association was found for every genotype (p > 0.05). Further subgroup stratification by ethnicity and weight did not lead to discovery of significant correlation (p > 0.05). For rs2059806, four studies including 442 controls and 524 PCOS cases were qualified for meta-analysis, and no significant association with PCOS was found for any genotype (p > 0.05). Four studies including 12,830 controls and 11,683 PCOS cases investigated the correlation between rs2059807 and PCOS, and five of the six cohorts indicated a significant impact. Our current meta-analysis suggests no significant correlation between rs1799817/rs2059806 SNPs and susceptibility of PCOS, while rs2059807 could be a promising candidate SNP that might be involved in the susceptibility of PCOS.

Role of mtDNA haplogroups in the prevalence of osteoarthritis in different geographic populations: a meta-analysis.

BACKGROUND: Osteoarthritis (OA) is the most common form of arthritis and has become an increasingly important public-health problem. However, the pathogenesis of OA is still unclear. In recent years, its correlation with mtDNA haplogroups attracts much attention. We aimed to perform a meta-analysis to investigate the association between mtDNA haplogroups and OA. METHODS: Published English or Chinese literature from PubMed, Web of Science, SDOS, and CNKI was retrieved up until April 15, 2014. Case-control or cohort studies that detected the frequency of mtDNA haplogroups in OA patients and controls were included. The quality of the included studies was evaluated by the Newcastle-Ottawa Scale (NOS) assessment. A meta-analysis was conducted to calculate pooled odds ratio (OR) with 95% confidence interval (CI) through the random or fixed effect model, which was selected based on the between-study heterogeneity assessed by Q test and I2 test. Subgroup analysis was performed to explore the origin of heterogeneity. RESULTS: A total of 6 case-control studies (10590 cases and 7161 controls) with an average NOS score of 6.9 were involved. For the analysis between mtDNA haplogroup J and OA, random model was selected due to high heterogeneity. No significant association was found initially (OR = 0.73, 95%CI: 0.52-1.03), however, once any study from UK population was removed the association emerged. Further subgroup analysis demonstrated that there was a significant association in Spain population (OR = 0.57, 95%CI: 0.46-0.71), but not in UK population. Also, subgroup analysis revealed that there was a significant correlation between cluster TJ and OA in Spain population (OR = 0.70, 95%CI: 0.58-0.84), although not in UK population. No significant correlation was found between haplogroup T/cluster HV/cluster KU and OA. CONCLUSIONS: Our current meta-analysis suggests that mtDNA haplogroup J and cluster TJ correlate with the risk of OA in Spanish population, but the associations in other populations require further investigation.