Published Online: December 16, 2013. doi:10.1001/jamainternmed.2013.12765.
Study concept and design: Both authors.
Acquisition of data: Grey.
Analysis and interpretation of data: Both authors.
Drafting of the manuscript: Grey.
Critical revision of the manuscript for important intellectual content: Bolland.
Conflict of Interest Disclosures: None reported.
Funding/Support: The Health Research Council of New Zealand.
Role of the Sponsor: The Health Research Council of New Zealand had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.