title: Effect of Carotene and Lycopene on the Risk of Prostate Cancer: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies.
abstract: BACKGROUND
  Many epidemiologic studies have investigated the association between carotenoids intake and risk of Prostate cancer (PCa). However, results have been inconclusive.
  
  
  METHODS
  We conducted a systematic review and dose-response meta-analysis of dietary intake or blood concentrations of carotenoids in relation to PCa risk. We summarized the data from 34 eligible studies (10 cohort, 11 nested case-control and 13 case-control studies) and estimated summary Risk Ratios (RRs) and 95% confidence intervals (CIs) using random-effects models.
  
  
  RESULTS
  Neither dietary β-carotene intake nor its blood levels was associated with reduced PCa risk. Dietary α-carotene intake and lycopene consumption (both dietary intake and its blood levels) were all associated with reduced risk of PCa (RR for dietary α-carotene intake: 0.87, 95%CI: 0.76-0.99; RR for dietary lycopene intake: 0.86, 95%CI: 0.75-0.98; RR for blood lycopene levels: 0.81, 95%CI: 0.69-0.96). However, neither blood α-carotene levels nor blood lycopene levels could reduce the risk of advanced PCa. Dose-response analysis indicated that risk of PCa was reduced by 2% per 0.2mg/day (95%CI: 0.96-0.99) increment of dietary α-carotene intake or 3% per 1mg/day (95%CI: 0.94-0.99) increment of dietary lycopene intake.
  
  
  CONCLUSIONS
  α-carotene and lycopene, but not β-carotene, were inversely associated with the risk of PCa. However, both α-carotene and lycopene could not lower the risk of advanced PCa.
authors.affiliation: Department of Clinical Laboratory, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, No.301 Middle Yanchang Road, Zhabei District, Shanghai 200072, China.
authors.forename: Yulan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Oncology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, No.301 Middle Yanchang Road, Zhabei District, Shanghai 200072, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Cui
authors.affiliation: Department of Oncology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, No.301 Middle Yanchang Road, Zhabei District, Shanghai 200072, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Department of Oncology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, No.301 Middle Yanchang Road, Zhabei District, Shanghai 200072, China.
authors.forename: Juemin
authors.initials: J
authors.lastname: Fang
authors.affiliation: Department of Oncology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, No.301 Middle Yanchang Road, Zhabei District, Shanghai 200072, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Xu
mesh_terms: D002338:Carotenoids / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D000077276:Lycopene; D008297:Male; D064887:Observational Studies as Topic; D011471:Prostatic Neoplasms / Q000453:epidemiology*; D012306:Risk
chemical_list: D002338:Carotenoids; D000077276:Lycopene