title: Intake and Biomarkers of Folate and Risk of Cancer Morbidity in Older Adults, NHANES 1999-2002 with Medicare Linkage.
abstract: BACKGROUND
  After the 1998 mandatory folic acid fortification of enriched cereal-grain products in the U.S., safety concerns were raised that excess consumption of folic acid and high blood folate biomarkers detected in adults may increase the risk of certain types of cancer.
  
  
  METHODS
  Baseline data from about 1400 participants in the National Health and Nutrition Examination Survey (NHANES) 1999-2002, aged ≥ 57 years were linked to Medicare and mortality files through December 31, 2007. Using cox proportional hazards regression models, we assessed associations between dietary folate equivalents, folate biomarkers, the presence of unmetabolized folic acid and, overall cancer incidence.
  
  
  RESULTS
  With 8,114 person-years of follow-up (median follow-up, 6.3 years), about 125 cancer cases were identified. After adjusting for confounders, the hazard ratios of the highest quartile versus the second quartile of RBC folate and dietary folate equivalents were 0.54 (95% CI: 0.31-0.93) and 0.54 (95% CI: 0.30-0.95), respectively. Additionally, serum and RBC folate as continuous variables were inversely and significantly associated with cancer incidence (p<0.01). No significant associations were observed between the presence of unmetabolized folic acid, intake of naturally-occurring food folate or folic acid separately, and cancer incidence.
  
  
  CONCLUSIONS
  High total folate intake and biomarkers in older adults appear to be protective against cancer in post-folic acid fortification years. This study does not show a negative impact of current level of folic acid fortification on cancer risk. As this is one of the few studies to examine the association between unmetabolized folic acid and cancer outcome, a study including a larger nationwide representative sample of the U.S. population is needed.
authors: University of Maryland, Department of Nutrition and Food Science, College Park, Maryland, United States of America.
authors: Jing
authors: J
authors: Hu
authors: Office of Nutrition, Labeling and Dietary Supplements, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, College Park, Maryland, United States of America.
authors: WenYen
authors: W
authors: Juan
authors: University of Maryland, Department of Nutrition and Food Science, College Park, Maryland, United States of America.
authors: Nadine R
authors: NR
authors: Sahyoun
mesh_terms: D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology; D000886:Anthropometry; D015415:Biomarkers; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood; D005527:Food, Fortified; D006801:Humans; D015994:Incidence; D008019:Life Style; D008297:Male; D006278:Medicare; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D009749:Nutrition Surveys; D016016:Proportional Hazards Models; D012306:Risk; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors; D014481:United States
chemical_list: D015415:Biomarkers; D005492:Folic Acid