title: The Association between Leptin Level and Breast Cancer: A Meta-Analysis.
abstract: Contradictory results have been reported regarding the association between leptin level and breast cancer. Therefore, a meta-analysis was performed to investigate this issue.
  
  
  
  Published literature from PubMed and the Chinese National Knowledge Infrastructure (CNKI) Database was retrieved. This study was performed based on different cases and control groups. The combined effect ([Formula: see text]) with 95% confidence interval (CI) was calculated using fixed-effects or random-effects model analysis.
  
  
  
  Overall, the mean serum leptin level of case groups was significantly higher than that of control groups. A) For 9 studies comparing breast cancer cases and healthy controls the combined effect [Formula: see text] was 0.58 with 95% CI (0.48, 0.68). B) For 4 studies comparing premenopausal breast cancer cases and healthy controls the [Formula: see text] was 0.32 (0.12, 0.52). C) For 5 studies comparing postmenopausal cases and healthy controls the [Formula: see text] was 0.65 (0.46, 0.84). D) For 4 studies comparing breast cancer cases and breast benign controls the [Formula: see text] was 0.38 (0.17, 0.59). E) For 2 studies comparing premenopausal breast cancer cases and breast benign controls the [Formula: see text] was 0.33 (-0.25, 0.91). F) For 6 studies comparing postmenopausal breast cancer cases and breast benign controls the [Formula: see text] was 0.39 (0.19, 0.60). G) For 4 studies comparing lymph node metastasis positive cases and negative controls the [Formula: see text] was 0.72 (0.45, 1.00). H) For 3 studies comparing breast benign cases and healthy controls the [Formula: see text] was 0.71 (0.41, 1.01).
  
  
  
  This meta-analysis suggests that leptin level plays a role in breast cancer and has potential for development as a diagnostic tool.
authors.affiliation: Department of Epidemiology and Statistics, School of Public Health, Hebei Medical University, Hebei, Shijiazhuang, China.
authors.forename: Jingping
authors.initials: J
authors.lastname: Niu
authors.forename: Le
authors.initials: L
authors.lastname: Jiang
authors.forename: Weiheng
authors.initials: W
authors.lastname: Guo
authors.forename: Liang
authors.initials: L
authors.lastname: Shao
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Liqin
authors.initials: L
authors.lastname: Wang
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood / Q000175:diagnosis*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008207:Lymphatic Metastasis; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; D020738:Leptin