title: Serum folate levels and fatality among diabetic adults: A 15-y follow-up study of a national cohort.
abstract: OBJECTIVE
  Folate is involved in carbohydrate metabolism, a process that can have clinical implications regarding diabetes management. The aim of this study was to assess the relationship between serum folate and fatality among adults with diabetes.
  
  
  METHODS
  A retrospective cohort study was conducted with 532 adults with diabetes who participated in Phase II of NHANES III (National Health and Nutrition Examination Survey III; 1991-1994). This study served as baseline and was linked to the National Death Index database for a 15-y (1991-2006) follow-up study. Estimates of hazard ratios (HRs) for all-cause and cancer-related deaths, cardiovascular disease (CVD), and diabetes for individuals with different serum folate levels were obtained from Cox proportional hazards regression.
  
  
  RESULTS
  The mean age of adults with diabetes and detected serum folate at baseline was 63.2 y (SD 13.8 y). During follow-up, diabetes was listed as a contributor for 138 of 299 deaths. For all-cause deaths, the fatality rate of the upper quartile (74.30/1000 person-years [PY]) was almost twofold higher than the lower quartile (41.75/1000 PY) of serum folate levels. After adjusting for several covariates, including serum vitamin B12, cotinine, homocysteine and CVD history at baseline; the HRs for all-cause fatalities were 1.00 (reference), 1.62 (95% confidence interval [CI], 1.06-2.47) and 1.76 (95% CI, 1.09-2.83) among adults with diabetes in the lower, intermediate, and upper quartiles of serum folate levels, respectively.
  
  
  CONCLUSIONS
  Results indicate that high serum folate concentrations are associated with an increased fatality risk among adults with diabetes. Further studies are warranted to determine the mechanism(s) of this phenomenon.
authors.affiliation: Departments of Environmental Health Sciences and Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA. Electronic address: evansafriyiegyawu@georgiasouthern.edu.
authors.forename: Evans
authors.initials: E
authors.lastname: Afriyie-Gyawu
authors.affiliation: Departments of Environmental Health Sciences and Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA.
authors.forename: Emeka
authors.initials: E
authors.lastname: Ifebi
authors.affiliation: Department of Fisheries & Aquatic Resources Management, Faculty of Renewable Natural Resources, University for Development Studies, Tamale, Ghana.
authors.forename: Akwasi
authors.initials: A
authors.lastname: Ampofo-Yeboah
authors.affiliation: Departments of Environmental Health Sciences and Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA.
authors.forename: Brittany
authors.initials: B
authors.lastname: Kyte
authors.affiliation: Departments of Environmental Health Sciences and Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA.
authors.forename: Sambridhi
authors.initials: S
authors.lastname: Shrestha
authors.affiliation: Departments of Environmental Health Sciences and Epidemiology, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000097:blood / Q000401:mortality*; D003367:Cotinine / Q000097:blood; D003920:Diabetes Mellitus / Q000097:blood / Q000401:mortality*; D005260:Female; D005492:Folic Acid / Q000097:blood*; D005500:Follow-Up Studies; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood / Q000401:mortality*; D009749:Nutrition Surveys; D016016:Proportional Hazards Models; D012189:Retrospective Studies; 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; Diabetic adults; Fatality; Folic acid; Retrospective cohort study; Serum folate