title: Native American ancestry, lung function, and COPD in Costa Ricans.
abstract: BACKGROUND
  Whether Native American ancestry (NAA) is associated with COPD or lung function in a racially admixed Hispanic population is unknown.
  
  
  METHODS
  We recruited 578 Costa Ricans with and without COPD into a hybrid case-control/family-based cohort, including 316 members of families of index case subjects. All participants completed questionnaires and spirometry and gave a blood sample for DNA extraction. Genome-wide genotyping was conducted with the Illumina Human610-Quad and HumanOmniExpress BeadChip kits (Illumina Inc), and individual ancestral proportions were estimated from these genotypic data and reference panels. For unrelated individuals, linear or logistic regression was used for the analysis of NAA and COPD (GOLD [Global Initiative for Chronic Obstructive Lung Disease] stage II or greater) or lung function. For extended families, linear mixed models and generalized estimating equations were used for the analysis. All models were adjusted for age, sex, educational level, and smoking behavior; models for FEV1 were also adjusted for height.
  
  
  RESULTS
  The average proportion of European, Native American, and African ancestry among participants was 62%, 35%, and 3%, respectively. After adjustment for current smoking and other covariates, NAA was inversely associated with COPD (OR per 10% increment, 0.55; 95% CI, 0.41-0.75) but positively associated with FEV1, FVC, and FEV1/FVC. After additional adjustment for pack-years of smoking, the association between NAA and COPD or lung function measures was slightly attenuated. We found that about 31% of the estimated effect of NAA on COPD is mediated by pack-years of smoking.
  
  
  CONCLUSIONS
  NAA is inversely associated with COPD but positively associated with FEV1 or FVC in Costa Ricans. Ancestral effects on smoking behavior partly explain the findings for COPD but not for FEV1 or FVC.
authors.affiliation: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA.
authors.forename: John M
authors.initials: JM
authors.lastname: Brehm
authors.affiliation: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA.
authors.forename: Nadia
authors.initials: N
authors.lastname: Boutaoui
authors.affiliation: Division of Pediatric Pulmonology, Hospital Nacional de Niños, San José, Costa Rica.
authors.forename: Manuel
authors.initials: M
authors.lastname: Soto-Quiros
authors.affiliation: Division of Pediatric Pulmonology, Hospital Nacional de Niños, San José, Costa Rica.
authors.forename: Lydiana
authors.initials: L
authors.lastname: Avila
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, MA.
authors.forename: Bartolome R
authors.initials: BR
authors.lastname: Celli
authors.affiliation: Lovelace Respiratory Research Institute, Albuquerque, NM.
authors.forename: Shannon
authors.initials: S
authors.lastname: Bruse
authors.affiliation: Lovelace Respiratory Research Institute, Albuquerque, NM.
authors.forename: Yohannes
authors.initials: Y
authors.lastname: Tesfaigzi
authors.affiliation: Division of Pulmonary Medicine, Allergy and Immunology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Celedón
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003364:Costa Rica; D005260:Female; D005541:Forced Expiratory Volume; D005838:Genotype; D006630:Hispanic or Latino / Q000235:genetics*; D006801:Humans; D007198:Indians, North American / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics* / Q000503:physiopathology*; D012907:Smoking / Q000235:genetics / Q000503:physiopathology; D014797:Vital Capacity