Published online: December 19, 2011 (doi:10.1001/jama.2011.1949).
Author Contributions: Dr Wilkinson 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: Wilkinson, Silverstein.
Acquisition of data: Wilkinson, Fahey, Suther.
Analysis and interpretation of data: Wilkinson, Fahey, Cabral, Silverstein.
Drafting of the manuscript: Wilkinson, Fahey, Suther, Cabral, Silverstein.
Critical revision of the manuscript for important intellectual content: Cabral, Silverstein.
Statistical analysis: Wilkinson, Cabral, Silverstein.
Administrative, technical or material support: Wilkinson, Fahey, Suther.
Study supervision: Wilkinson, Silverstein.
Obtained funding: Wilkinson, Silverstein.
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: The Joel and Barbara Alpert Endowment for the Children of the City and Boston University School of Medicine provided funding for the study.
Role of the Sponsors: The Joel and Barbara Alpert Endowment for the Children of the City and Boston University School of Medicine did not play any role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.
Additional Contributions: We thank Christine Shields, RN, who contributed greatly to the data collection as a paid research assistant. (Ms Shields is now with South Shore Home and Health Resources, Braintree, Massachusetts.)