title: High red blood cell folate is associated with an increased risk of death among adults with diabetes, a 15-year follow-up of a national cohort.
abstract: OBJECTIVE
  To describe the mortality and fatality of diabetes and assess their relationship with the level of red blood cell (RBC) folate.
  
  
  RESULTS
  We analyzed the data of 526 adults with diabetes who participated in the National Health and Nutrition Examination Survey (1991-1994) as the baseline examination, and were followed up through December 31, 2006. Estimates of the hazard ratios (HRs) of selected death causes for individuals with different levels of RBC folate were obtained from Cox proportional hazards regression. A total of 295 deaths were recorded by the end of a 15-year follow-up with a mortality rate of 58.48 per 1000 person year (py). Diabetes was listed as a contributing cause for 136 deaths, accounting for 46.1% of the total deaths with a fatality rate 26.96 per 1000 py. Mortality rate for all-cause in the group with upper quartile of RBC folate was almost twice as high as that among the group with lower quartile, 82.75 vs. 44.10 per 1000 py. After adjusting for covariates, including serum concentration of vitamin B12, cotinine, homocysteine and the history of cardio-cerebral vascular diseases assessed at the baseline, the HRs for dying from any causes were 1.00 (reference), 1.82 (95% CI = 1.25-2.66) and 2.10 (1.37-3.20) among diabetic adults with lower, intermediate, and upper quartiles of RBC folate.
  
  
  CONCLUSIONS
  Diabetes was listed as a contributing cause for less than half of the deaths among adults with diabetes after 15+ years of follow-up; high RBC folate concentration was associated with an elevated risk of death among adults with diabetes.
authors.affiliation: Department of Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA 30460, USA.
authors.forename: B
authors.initials: B
authors.lastname: Kyte
authors.affiliation: Department of Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA 30460, USA.
authors.forename: E
authors.initials: E
authors.lastname: Ifebi
authors.affiliation: Department of Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA 30460, USA.
authors.forename: S
authors.initials: S
authors.lastname: Shrestha
authors.affiliation: Department of Environmental Health Sciences, Jiann-Ping Hsu College of Public Health, Georgia Southern University, GA 30460, USA.
authors.forename: S
authors.initials: S
authors.lastname: Charles
authors.affiliation: Veterans Affairs Medical Center - Augusta, GA 30904, USA.
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA 30460, USA. Electronic address: jianzhang@georgiasouthern.edu.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000368:Aged; D002423:Cause of Death; D002561:Cerebrovascular Disorders / Q000097:blood / Q000401:mortality; D015331:Cohort Studies; D003367:Cotinine / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000401:mortality*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000737:chemistry*; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000097:blood*; D005500:Follow-Up Studies; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D016016:Proportional Hazards Models; D012307:Risk Factors; D012959:Socioeconomic Factors; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D006710:Homocysteine; D005492:Folic Acid; D003367:Cotinine; D014805:Vitamin B 12
keywords: Diabetes; Fatality; Folate; Mortality; Red blood cell