1. Center for Occupational and Environmental Health, University of California, Irvine, CA 92617, USA
2. Office of Public Health Studies, Thompson School of Social Work & Public Health, University of Hawaii, Mānoa, Honolulu, HI 96822, USA
3. Department of Environmental Health Sciences, Fielding School of Public Health, University of California Los Angeles, Los Angeles, CA 90095, USA
4. School of Nursing, University of California, Los Angeles, CA 90095, USA
5. Discipline of Chiropractic, School of Health, Medical and Applied Sciences, CQUniversity, Brisbane, QLD 4000, Australia
6. Department of Clinical Education, Canadian Memorial Chiropractic College, Toronto, ON M2H 3J1, Canada
7. Employer Based Integrated Primary Care Health Centers, Stanford Health Care, National University of Health Sciences, San Diego, CA 92121, USA
8. Department of Neurology, University of California, Irvine, CA 92868, USA