title: Type 2 diabetes and gender differences in liver cancer by considering different confounding factors: a meta-analysis of cohort studies.
abstract: Questions remain uncertainty regarding the gender differences in the relationship between type 2 diabetes (T2DM) and liver cancer risk. By considering several confounding factors, we aimed to identify this issue according to a meta-analysis of cohort studies.
  
  
  
  We searched EMBASE and MEDLINE for studies on the association between T2DM and risk of liver cancer up to November 30, 2014. A random-effects model was performed to calculate summary relative risks (SRRs) with corresponding 95% confidence intervals (CIs).
  
  
  
  A total of 24 cohort studies (including more than 20,000 liver cancer cases) were recruited. T2DM was associated with an elevated liver cancer incidence in both men (SRR = 2.16; 95% CI, 1.74-2.69) and women (SRR = 1.85; 95% CI, 1.40-2.44). Stratified analyses showed that the risk associations were significantly stronger in non-Asian than those in Asian for both men and women. Both tobacco smoking and body mass index were significant confounding factors for the T2DM-liver cancer association in men, whereas alcohol use was not the case. The SRR estimates of liver cancer mortality with T2DM were statistically significant in both men and women (men: SRR = 2.26; 95% CI, 1.60-3.19 and women: SRR = 2.01; 95% CI, 1.45-2.74).
  
  
  
  Results of this meta-analysis indicate that the T2DM-liver cancer correlation is confounded by smoking and body mass index in both men and women. Results also suggest a significantly stronger T2DM-liver cancer correlation in non-Asian than that in Asian for both men and women.
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, People's Republic of China.
authors.forename: Yuqin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, People's Republic of China.
authors.forename: Baochan
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, People's Republic of China.
authors.forename: Shiyan
authors.initials: S
authors.lastname: Yan
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Shen
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, People's Republic of China.
authors.forename: Haixia
authors.initials: H
authors.lastname: Cao
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, People's Republic of China.
authors.forename: Jiangao
authors.initials: J
authors.lastname: Fan
authors.affiliation: Department of Gynaecology and Obstetrics, Xinhua Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, People's Republic of China. Electronic address: zhangrr_dr@126.com.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of General Surgery, Xinhua Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, People's Republic of China. Electronic address: Jung0011@126.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Gu
mesh_terms: D015992:Body Mass Index; D015331:Cohort Studies; D015897:Comorbidity; D015986:Confounding Factors, Epidemiologic; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008113:Liver Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D011379:Prognosis; D018570:Risk Assessment; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology*; D016019:Survival Analysis
keywords: Cohort study; Liver cancer; Meta-analysis; Type 2 diabetes