title: Leptin and leptin receptor gene polymorphisms in obstructive sleep apnea: a HuGE review and meta-analysis.
abstract: BACKGROUND
  Several epidemiological studies have been conducted to examine the association between leptin and leptin receptor (LEPR) gene polymorphisms and risk of obstructive sleep apnea (OSA). However, the results remain conflicting rather than conclusive.
  
  
  OBJECTIVE
  The aim of this study was to investigate associations of leptin and LEPR polymorphisms and risk of OSA.
  
  
  METHODS
  We carried out a search in MEDLINE, EMBASE, and Chinese National Knowledge Infrastructure (CNKI) databases for relevant studies. Data were extracted using a standardized form and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the association.
  
  
  RESULTS
  Overall, no statistically significant association of OSA risk and polymorphisms of Gln233Arg, Lys109Arg, Lys656Asn, 19A/G, Pro1019Arg, and 2548G/A was found. However, in the stratified analysis by ethnicity, Gln233Arg polymorphism was associated with a significantly decreased risk of OSA in European (homozygote comparison: OR = 0.35, 95% CI = 0.14-0.85, P = 0.02), but not for Asian population.
  
  
  CONCLUSIONS
  Our study suggested that leptin and LEPR polymorphisms had no association with OSA risk in all examined patients, whereas there was an association between Gln233Arg polymorphism and OSA risk in Europeans.
authors.affiliation: Department of Respiratory Medicine, Affiliated Hospital of School of Medicine, Ningbo University, Ningbo, 315020, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Lv
authors.forename: Lin
authors.initials: L
authors.lastname: Tan
authors.forename: Yanping
authors.initials: Y
authors.lastname: Wu
authors.forename: Chao
authors.initials: C
authors.lastname: Cao
authors.forename: Zaichun
authors.initials: Z
authors.lastname: Deng
mesh_terms: D000483:Alleles; D001208:Asia; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D005060:Europe; D006801:Humans; D020738:Leptin / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D054411:Receptors, Leptin / Q000235:genetics*; D012306:Risk; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology / Q000235:genetics*; D013223:Statistics as Topic
chemical_list: C515448:LEPR protein, human; D020738:Leptin; D054411:Receptors, Leptin