1. Sean N Parker Center for Allergy and Asthma Research, Division of Pulmonary and Critical Care Medicine and Division of Allergy, Immunology and Rheumatology, Stanford University, Stanford, CA, USA
2. Department for Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
3. Department of Medicine, Stanford University, Palo Alto, CA, USA
4. Institute of Health Research and Policy, University of Illinois at Chicago, Chicago, IL, USA
5. Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
6. Department of Allergy, Asthma and Immunology, Kaiser Permanente San Francisco, San Francisco, CA, USA
7. Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA