Published Online: June 17, 2013. doi:10.1001/jamainternmed.2013.6835.
Study concept and design: All authors.
Acquisition of data: Kohlmann, Gierk, Hümmelgen.
Analysis and interpretation of data: Kohlmann, Gierk, Hümmelgen, Löwe.
Drafting of the manuscript: Kohlmann, Gierk, Hümmelgen, Löwe.
Critical revision of the manuscript for important intellectual content: Kohlmann, Gierk, Hümmelgen, Blankenberg.
Statistical analysis: Kohlmann, Gierk.
Obtained funding: Löwe.
Administrative, technical, or material support: Kohlmann, Gierk, Hümmelgen.
Study supervision: Hümmelgen, Blankenberg, Löwe.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by grant 01-GX-1004 from the German Ministry of Education and Science.
Additional Contributions: Alexandra Murray, PhD, provided helpful comments and suggestions on earlier drafts of this Research Letter. Dr Murray did not receive any compensation for her work.