title: Prediabetes and the risk of cancer: a meta-analysis.
abstract: OBJECTIVE
  The results from prospective cohort studies of prediabetes (impaired fasting glucose and/or impaired glucose tolerance) and risk of cancer are controversial. We conducted a meta-analysis to evaluate the risk of cancer in association with impaired fasting glucose and impaired glucose tolerance.
  
  
  METHODS
  The PubMed, EMBASE and Cochrane Library databases were searched for prospective cohort studies with data on prediabetes and cancer. Two independent reviewers assessed the reports and extracted the data. Prospective studies were included if they reported adjusted RRs with 95% CIs for the association between cancer and prediabetes. Subgroup analyses were conducted according to endpoint, age, sex, ethnicity, duration of follow-up and study characteristics.
  
  
  RESULTS
  Data from 891,426 participants were derived from 16 prospective cohort studies. Prediabetes was associated with an increased risk of cancer overall (RR 1.15; 95% CI 1.06, 1.23). The results were consistent across cancer endpoint, age, duration of follow-up and ethnicity. There was no significant difference for the risk of cancer with different definitions of prediabetes. In a site-specific cancer analysis, prediabetes was significantly associated with increased risks of cancer of the stomach/colorectum, liver, pancreas, breast and endometrium (all p < 0.05), but not associated with cancer of the bronchus/lung, prostate, ovary, kidney or bladder. The risks of site-specific cancer were significantly different (p = 0.01) and were highest for liver, endometrial and stomach/colorectal cancer.
  
  
  CONCLUSIONS
  Overall, prediabetes was associated with an increased risk of cancer, especially liver, endometrial and stomach/colorectal cancer.
authors.affiliation: Clinical Medicine Research Center, The First People's Hospital of Shunde, Penglai Road, Daliang Town, Shunde District, Foshan, 528300, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Huang
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Cai
authors.forename: Miaozhen
authors.initials: M
authors.lastname: Qiu
authors.forename: Peisong
authors.initials: P
authors.lastname: Chen
authors.forename: Hongfeng
authors.initials: H
authors.lastname: Tang
authors.forename: Yunzhao
authors.initials: Y
authors.lastname: Hu
authors.forename: Yuli
authors.initials: Y
authors.lastname: Huang
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D011236:Prediabetic State / Q000150:complications* / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors