title: Meta-analysis: circulating adiponectin levels and risk of colorectal cancer and adenoma.
abstract: OBJECTIVE
  To provide a systematic review with a meta-analysis for addressing the association between circulating adiponectin levels and the risk of colorectal cancer and adenoma.
  
  
  METHODS
  Multiple electronic sources including MEDLINE, EMBASE and the Science Citation Index Expanded databases were searched to identify relevant studies for this systematic review. All existing observational studies that examined the relationship between circulating adiponectin and colorectal cancer or adenoma were included. Weighted mean difference and 95% confidence intervals (CI) were estimated and pooled using meta-analysis methods.
  
  
  RESULTS
  Overall 13 case control or nested case control studies met the inclusion criteria. A total of 6175 participants and 3015 cases of colorectal cancer and adenoma were included in this meta-analysis. The weighted mean difference (95% CI) were -1.084 µg/mL (-1.836, -0.331), P = 0.005 in colorectal cancer and -1.43 µg/mL (-2.231, -0.628), P = 0.000 in adenoma. In men, a 2% decreased risk of colorectal neoplasm for a 1 µg/mL increment in adiponectin levels was observed (OR = 0.98, 95% CI 0.96-0.99) whereas among women there is no evidence of such a trend (OR = 0.99, 95% CI 0.97-1.01).
  
  
  CONCLUSIONS
  Patients with colorectal cancer and adenoma demonstrated markedly lower adiponectin values than controls, yet there was significant heterogeneity among studies. A negative dose response relationship between levels of adiponectin and the risk of colorectal neoplasm was observed in men.
authors.affiliation: Department of Gastroenterology, Renji Hospital, Shanghai Jiaotong University School of Medicine Shanghai Institute of Digestive Disease, Shanghai, China.
authors.forename: Xi Tao
authors.initials: XT
authors.lastname: Xu
authors.forename: Qi
authors.initials: Q
authors.lastname: Xu
authors.forename: Jin Lu
authors.initials: JL
authors.lastname: Tong
authors.forename: Ming Ming
authors.initials: MM
authors.lastname: Zhu
authors.forename: Mei Lan
authors.initials: ML
authors.lastname: Huang
authors.forename: Zhi Hua
authors.initials: ZH
authors.lastname: Ran
authors.forename: Shu Dong
authors.initials: SD
authors.lastname: Xiao
mesh_terms: D000236:Adenoma / Q000097:blood / Q000453:epidemiology*; D052242:Adiponectin / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000097:blood / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D052242:Adiponectin; D015415:Biomarkers