title: Risk factors for rectal cancer and methylenetetrahydrofolate reductase polymorphisms in a population in Northeast Thailand.
abstract: OBJECTIVE
  Polymorphisms in methylenetetrahydrofolate reductase (MTHFR) are known to be associated with predisposition for certain cancers. This study aimed to evaluate the effects of lifestyle factors, family history and genetic polymorphisms in MTHFR C677T and A1298C on rectal cancer risk and possible interactions with lifestyle factors in Northeast Thailand.
  
  
  METHODS
  A hospital-based case-control study was conducted during 2002-2006 with recruitment of 112 rectal cancer cases and 242 non-rectal cancer patient controls. Information was collected using a structured-questionnaire. Blood samples were obtained for assay of MTHFR C677T and A1298C genotypes by polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) techniques. Associations between lifestyle factors, family history and genetic polymorphisms v.s. rectal cancer risk were assessed using logistic regression analysis.
  
  
  RESULTS
  Subjects with frequent and occasional constipation had a higher risk (OR adj.=14.64; 95%CI=4.28-50.04 and OR adj.=2.15; 95%CI=1.14-4.06), along with those who reported ever having hemorrhoids (OR adj.=2.82; 95%CI=1.36-5.84) or a family history of cancer (OR adj.=1.90; 95%CI=1.06-3.39). Consumption of a high level of pork was also associated with risk (OR adj.=1.82; 95%CI=1.05-3.15). Interactions were not observed between MTHFR and other risk factors.
  
  
  CONCLUSIONS
  This study suggested that the risk factors for rectal cancer in the Thai population are bowel habits, having had hemorrhoids, a family history of cancer and pork consumption.
authors.affiliation: Department of Epidemiology, Faculty of Public Health, Khon Kaen University, Thailand. supannee@kku.ac.th
authors.forename: Supannee
authors.initials: S
authors.lastname: Promthet
authors.forename: Chamsai
authors.initials: C
authors.lastname: Pientong
authors.forename: Tipaya
authors.initials: T
authors.lastname: Ekalaksananan
authors.forename: Nopparat
authors.initials: N
authors.lastname: Songserm
authors.forename: Kirati
authors.initials: K
authors.lastname: Poomphakwaen
authors.forename: Peechanika
authors.initials: P
authors.lastname: Chopjitt
authors.forename: Surapon
authors.initials: S
authors.lastname: Wiangnon
authors.forename: Shinkan
authors.initials: S
authors.lastname: Tokudome
mesh_terms: D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011379:Prognosis; D012004:Rectal Neoplasms / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D013785:Thailand / Q000453:epidemiology
chemical_list: C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)