African ancestry and lung function in Puerto Rican children

Background Puerto Rican and African American subjects share a significant proportion of African ancestry. Recent findings suggest that African ancestry influences lung function in African American adults. Objective We sought to examine whether a greater proportion of African ancestry is associated with lower FEV1 and forced vital capacity (FVC) in Puerto Rican children independently of socioeconomic status, health care access, or key environmental/lifestyle factors. Methods We performed a cross-sectional case-control study of 943 Puerto Rican children aged 6 to 14 years with (n = 520) and without (n = 423) asthma (defined as physician-diagnosed asthma and wheeze in the prior year) living in Hartford, Connecticut (n = 383), and San Juan, Puerto Rico (n = 560). We estimated the percentage of African racial ancestry in study participants using genome-wide genotypic data. We tested whether African ancestry is associated with FEV1 and FVC using linear regression. Multivariate models were adjusted for indicators of socioeconomic status and health care and selected environmental/lifestyle exposures. Results After adjustment for household income and other covariates, each 20% increment in African ancestry was significantly associated with lower prebronchodilator FEV1 (−105 mL; 95% CI, −159 to −51 mL; P < .001) and FVC (−133 mL; 95% CI, −197 to −69 mL; P < .001) and postbronchodilator FEV1 (−152 mL; 95% CI, −210 to −94 mL; P < .001) and FVC (−145 mL; 95% CI, −211 to −79 mL; P < .001) in children with asthma. Similar but weaker associations were found for prebronchodilator and postbronchodilator FEV1 (change for each 20% increment in African ancestry, −78 mL; 95% CI, −131 to −25 mL; P = .004) and for postbronchodilator FVC among children without asthma. Conclusions Genetic factors, environmental/lifestyle factors, or both correlated with African ancestry might influence childhood lung function in Puerto Rican subjects.