title: Role of mtDNA haplogroups in the prevalence of osteoarthritis in different geographic populations: a meta-analysis.
abstract: 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.
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhejiang Chinese Medicine University, Hangzhou, Zhejiang, China.
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Shen
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhejiang Chinese Medicine University, Hangzhou, Zhejiang, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Feng
authors.affiliation: Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Feng
mesh_terms: D000368:Aged; D004272:DNA, Mitochondrial / Q000235:genetics*; D005828:Genetics, Population; D005843:Geography; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D008875:Middle Aged; D010003:Osteoarthritis / Q000235:genetics; D015995:Prevalence; D017594:Publication Bias; D012307:Risk Factors
chemical_list: D004272:DNA, Mitochondrial