title: Association of leptin gene -2548 G/A polymorphism with obesity: a meta-analysis.
abstract: BACKGROUND
  A common single-nucleotide polymorphism identified in the 5'-untranslated region of the leptin gene (LEP -2548 G/A polymorphism) may be associated with obesity, but the existing research findings are inconsistent, so we conducted this meta-analysis.
  
  
  METHODS
  Medline, Embase and ISI Web of Science databases were searched to identify relevant studies. Meta-analysis of the total and subgroup populations was conducted using allelic, additive, dominant and recessive models, and odds ratios and their 95% confidence intervals were calculated in a fixed-effect model if no heterogeneity (evaluated as I(2) statistic) existed. Otherwise, a random-effects model was adopted. Subgroup analysis was performed by ethnicity. Meta-regression and the HETRED analysis were used to explore the potential sources of between-study heterogeneity. Egger's test and influence analysis were conducted to evaluate the publication bias and study power, respectively.
  
  
  RESULTS
  The final selection enrolled 9 studies, including 2,988 subjects (1,372 obese subjects and 1,616 controls). No significant association was identified between the LEP -2548 G/A polymorphism and obesity for all genetic models in the overall population and Caucasians. We found a significant association with allelic, additive and dominant models for subjects of mixed race from South America. Notwithstanding, this significance should be treated cautiously for it is based on a rather small sample (788 involved subjects).
  
  
  CONCLUSIONS
  In total, the combined analysis of data from current and published studies suggested that the LEP -2548 G/A polymorphism does not contribute to the development of obesity, despite the fact that a significant association exists in a small subgroup from South America. Further studies are needed to elucidate the relationship. .
authors.affiliation: Department of Nutrition and Food Hygiene, Zhejiang Academy of Medical Sciences, Hangzhou, PR China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Lin-Hong
authors.initials: LH
authors.lastname: Yuan
authors.forename: Yun
authors.initials: Y
authors.lastname: Xiao
authors.forename: Ming-yang
authors.initials: MY
authors.lastname: Lu
authors.forename: Li-jing
authors.initials: LJ
authors.lastname: Zhang
authors.forename: Yin
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000483:Alleles; D016208:Databases, Factual; D005006:Ethnicity / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D020738:Leptin / Q000235:genetics*; D009765:Obesity / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors
chemical_list: D020738:Leptin