title: Use of folic acid-containing supplements after a diagnosis of colorectal cancer in the Colon Cancer Family Registry.
abstract: BACKGROUND
  Supplement use among cancer patients is high, and folic acid intake in particular may adversely affect the progression of colorectal cancer. Few studies have evaluated the use of folic acid-containing supplements (FAS) and its predictors in colorectal cancer patients.
  
  
  OBJECTIVE
  To assess the use of FAS, change in use, and its predictors after colorectal cancer diagnosis.
  
  
  METHODS
  We used logistic regression models to investigate predictors of FAS use and its initiation after colorectal cancer diagnosis in 1,092 patients recruited through the Colon Cancer Family Registry.
  
  
  RESULTS
  The prevalence of FAS use was 35.4% before and 55.1% after colorectal cancer diagnosis (P = 0.004). Women were more likely than men to use FAS after diagnosis [odds ratio (OR), 1.47; 95% confidence interval (95% CI), 1.14-1.89], as were those consuming more fruit (P(trend) < 0.0001) or vegetables (P(trend) = 0.001), and U.S. residents (P < 0.0001). Less likely to use FAS after diagnosis were nonwhite patients (OR, 0.66; 95% CI, 0.45-0.97), current smokers (OR, 0.67; 95% CI, 0.46-0.96), and those with higher meat intake (P(trend) = 0.03). Predictors of FAS initiation after diagnosis were generally similar to those of FAS use after diagnosis, although associations with race and vegetable intake were weaker and those with exercise stronger.
  
  
  CONCLUSIONS
  Our analysis showed substantial increases in the use of FAS after diagnosis with colorectal cancer, with use or initiation more likely among women, Caucasians, U.S. residents, and those with a health-promoting life-style.
  
  
  CONCLUSIONS
  Studies of cancer prognosis that rely on prediagnostic exposure information may result in substantial misclassification.
authors.affiliation: National Center for Tumor Diseases Heidelberg, Division of Preventive Oncology, German Cancer Research Center, Im Neuenheimer Feld 581, Heidelberg, Germany.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Holmes
authors.forename: Yingye
authors.initials: Y
authors.lastname: Zheng
authors.forename: John A
authors.initials: JA
authors.lastname: Baron
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.forename: Gail
authors.initials: G
authors.lastname: McKeown-Eyssen
authors.forename: Polly A
authors.initials: PA
authors.lastname: Newcomb
authors.forename: Mariana C
authors.initials: MC
authors.lastname: Stern
authors.forename: Robert W
authors.initials: RW
authors.lastname: Haile
authors.forename: William M
authors.initials: WM
authors.lastname: Grady
authors.forename: John D
authors.initials: JD
authors.lastname: Potter
authors.forename: Loic
authors.initials: L
authors.lastname: Le Marchand
authors.forename: Peter T
authors.initials: PT
authors.lastname: Campbell
authors.forename: Jane C
authors.initials: JC
authors.lastname: Figueiredo
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Limburg
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jenkins
authors.forename: John L
authors.initials: JL
authors.lastname: Hopper
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Ulrich
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000188:drug therapy*; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D005192:Family Health; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D005500:Follow-Up Studies; D015438:Health Behavior; D006801:Humans; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D011379:Prognosis; D012042:Registries; D012737:Sex Factors; D011795:Surveys and Questionnaires
chemical_list: D000970:Antineoplastic Agents; D005492:Folic Acid