Genetics of Asthma Susceptibility to Pollution (GASP)
The GASP study, conducted between 2012 and 2014, was a case-control plus longitudinal follow-up study enrolling 666 children 9-19 years of age with current or previous asthma and 571 children without asthma living in the peri-urban communities of Pampas de San Juan de Miraflores and Villa El Salvador in Lima, Peru. At baseline, we conducted severity assessments (NAEPP-3 and Asthma Control Test), anthropometric measurements, and a comprehensive questionnaire including information on socioeconomic status, other demographic variables, asthma family history, and exposure history. In addition, all children received pre- and post-bronchidlator spirometry (lung function) testing, exhaled nitric oxide testing, and blood draws at baseline. Sera were analyzed for total and antigen-specific IgE concentrations, as well as micronutrient (vitamin D, folate, zinc) concentrations. Children with asthma were followed up for a 6-9 month period on a bimonthly basis, during which we measured healthcare utilization and asthma control (Asthma Control Test). We also performed pre- and post-bronchodilator spirometry on children with asthma quarterly during follow-up. Finally, allergen testing in the household and gravimetric and real-time pollutant (PM2.5, black carbon, NO2) concentrations were measured in a subset of households, and inverse distance weighting methods were used to estimate household exposures to pollutants for each participating household.