title: Native American ancestry affects the risk for gene methylation in the lungs of Hispanic smokers from New Mexico.
abstract: BACKGROUND
  Gene promoter methylation detected in sputum predicts lung cancer risk in smokers. Compared with non-Hispanic whites (NHW), Hispanics have a lower age-standardized incidence for lung cancer.
  
  
  OBJECTIVE
  This study compared the methylation prevalence in sputum of NHWs with Hispanics using the Lovelace Smokers cohort (n = 1998) and evaluated the effect of Native American ancestry (NAA) and diet on biomarkers for lung cancer risk.
  
  
  METHODS
  Genetic ancestry was estimated using 48 ancestry markers. Diet was assessed by the Harvard University Dietary Assessment questionnaire. Methylation of 12 genes was measured in sputum using methylation-specific polymerase chain reaction. The association between NAA and risk for methylation was assessed using generalized estimating equations. The ethnic difference in the association between pack-years and risk for lung cancer was assessed in the New Mexico lung cancer study.
  
  
  RESULTS
  Overall Hispanics had a significantly increased risk for methylation across the 12 genes analyzed (odds ratio, 1.18; P = 0.007). However, the risk was reduced by 32% (P = 0.032) in Hispanics with high versus low NAA. In the New Mexico lung cancer study, Hispanic non-small cell lung cancer cases have significantly lower pack-years than NHW counterparts (P = 0.007). Furthermore, compared with NHW smokers, Hispanic smokers had a more rapidly increasing risk for lung cancer as a function of pack-years (P = 0.058).
  
  
  CONCLUSIONS
  NAA may be an important risk modifier for methylation in Hispanic smokers. Smoking intensity may have a greater impact on risk for lung cancer in Hispanics compared with NHWs.
authors.affiliation: 1 Lung Cancer Program, Lovelace Respiratory Research Institute, Albuquerque, New Mexico.
authors.forename: Shuguang
authors.initials: S
authors.lastname: Leng
authors.forename: Yushi
authors.initials: Y
authors.lastname: Liu
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Thomas
authors.forename: W James
authors.initials: WJ
authors.lastname: Gauderman
authors.forename: Maria A
authors.initials: MA
authors.lastname: Picchi
authors.forename: Shannon E
authors.initials: SE
authors.lastname: Bruse
authors.forename: Xiequn
authors.initials: X
authors.lastname: Zhang
authors.forename: Kristina G
authors.initials: KG
authors.lastname: Flores
authors.forename: David
authors.initials: D
authors.lastname: Van Den Berg
authors.forename: Christine A
authors.initials: CA
authors.lastname: Stidley
authors.forename: Frank D
authors.initials: FD
authors.lastname: Gilliland
authors.forename: Steven A
authors.initials: SA
authors.lastname: Belinsky
mesh_terms: D000368:Aged; D044467:American Indian or Alaska Native / Q000235:genetics*; D002289:Carcinoma, Non-Small-Cell Lung / Q000208:ethnology* / Q000235:genetics; D015331:Cohort Studies; D019175:DNA Methylation / Q000502:physiology*; D004032:Diet; D005260:Female; D005492:Folic Acid / Q000502:physiology; D006630:Hispanic or Latino / Q000235:genetics*; D006801:Humans; D008137:Longitudinal Studies; D008175:Lung Neoplasms / Q000208:ethnology* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009516:New Mexico; D011401:Promoter Regions, Genetic / Q000502:physiology; D012307:Risk Factors; D012907:Smoking / Q000208:ethnology* / Q000235:genetics; D013183:Sputum / Q000737:chemistry
chemical_list: D005492:Folic Acid
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