About the Authors

Randall S Stafford

To whom correspondence should be addressed. E-mail: rstafford@stanford.edu

Affiliation Program on Prevention Outcomes and Practices, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, United States of America

Veronica Monti

Affiliation Program on Prevention Outcomes and Practices, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, United States of America

Jun Ma

Affiliation Program on Prevention Outcomes and Practices, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

RSS obtained study funding. RSS and JM designed the study. RSS, VM, and JM analyzed the data and contributed to writing the paper.