title: One-Carbon Metabolic Factors and Risk of Renal Cell Cancer: A Meta-Analysis.
abstract: BACKGROUND
  Nutrients related to one-carbon metabolism were previously shown to be significantly associated with the risk of cancer. The aim of this meta-analysis was to evaluate potential relationships between one-carbon metabolic factors and renal cell cancer (RCC) risk.
  
  
  METHODS
  PubMed, EMBASE, and Cochrane Library databases were searched through March 2015 for observational studies of quantitative RCC risk estimates in relation to one-carbon metabolic factors. The relative risks (RRs) with 95% confidence intervals (CIs) measured the relationship between one-carbon metabolic factors and RCC risk using a random-effects model.
  
  
  RESULTS
  Of the 463 citations and abstracts identified by database search, seven cohorts from five observational studies reported data on 133,995 individuals, and included 2,441 RCC cases. Comparing the highest with the lowest category, the pooled RRs of RCC were 0.72 (95%CI: 0.52-1.00; P = 0.048) for vitamin B12. In addition, an increase in folic acid supplementation of 100 μg/day was associated with a 3% lower risk of RCC (RR, 0.97; 95%CI: 0.93-1.00; P = 0.048). Similarly, an increase of 5 nmol/L of vitamin B2 was associated with a reduced risk of RCC 0.94 (95%CI: 0.89-1.00; P = 0.045). Sensitivity analyses suggested that a higher serum vitamin B6 might contribute to a reduced risk of RCC (RR, 0.83; 95%CI: 0.77-0.89; P < 0.001).
  
  
  CONCLUSIONS
  Higher levels of serum vitamin B2, B6, B12, and folic acid supplementation lowered the risk of RCC among the study participants.
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Bijing
authors.initials: B
authors.lastname: Mao
authors.affiliation: Department of Epidemiology, College of Preventive Medicine, Third Military Medical University, Chongqing, 400038, China.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Li
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Chen
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Ding
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lei
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Li
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Jiang
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Cancer Center, Institute of Surgical Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Ge
authors.initials: G
authors.lastname: Wang
mesh_terms: D015415:Biomarkers; D002244:Carbon / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism*; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism*; D008297:Male; D016017:Odds Ratio; D012306:Risk
chemical_list: D015415:Biomarkers; D002244:Carbon