Author Contributions: Dr Hong had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Hong, Atlas, Chang, Subramanian, Barry, Grant.
Acquisition of data: Hong, Atlas, Ashburner.
Analysis and interpretation of data: Hong, Atlas, Chang, Subramanian, Ashburner, Grant.
Drafting of the manuscript: Hong, Grant.
Critical revision of the manuscript for important intellectual content: Hong, Atlas, Chang, Subramanian, Ashburner, Barry, Grant.
Statistical analysis: Hong, Chang, Subramanian, Ashburner.
Obtained funding: Grant.
Administrative, technical, or material support: Hong, Atlas, Ashburner.
Study supervision: Atlas, Subramanian, Grant.
Financial Disclosures: None reported.
Funding/Support: Dr Hong is supported by National Research Service Award grant T32 HP12706 from the National Institutes of Health. Dr Grant is supported by career development grant NIDDK K23 DK067452 from the National Institutes of Health. Dr Atlas is supported by grant R18 HS018161 from the Agency for Healthcare Research and Quality. Dr Subramanian is supported by career development grant NHLBI K25 HL081275 from the National Institutes of Health.
Role of the Sponsor: The National Institutes of Health did not participate in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.
Additional Contributions: Timothy Ferris, MD, MPH, the medical director of the Massachusetts General Physicians Organization and associate professor of medicine at Harvard Medical School, provided helpful discussions on the manuscript. Dr Ferris did not receive any compensation for his contribution. Guoping Huang from the Harvard University Center for Geographic Analysis helped us create the US Census block group data on socioeconomic status using geo-codes. The Harvard University Center for Geographic Analysis was paid a small fee for these services.