Author Contributions: Dr Stephansson 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: Stephansson, Kieler, Haglund, Artama, Engeland, Gissler, Nørgaard, Valdimardóttir.
Acquisition of data: Kieler, Haglund, Engeland, Furu, Gissler, Nørgaard, Nielsen, Zoega, Valdimardóttir.
Analysis and interpretation of data: Stephansson, Kieler, Haglund, Engeland, Nørgaard, Zoega, Valdimardóttir.
Drafting of the manuscript: Stephansson, Valdimardóttir.
Critical revision of the manuscript for important intellectual content: Stephansson, Kieler, Haglund, Artama, Engeland, Furu, Gissler, Nørgaard, Nielsen, Zoega, Valdimardóttir.
Statistical analysis: Haglund.
Obtained funding: Kieler.
Administrative, technical, or material support: Kieler, Haglund, Artama, Nørgaard, Zoega.
Study supervision: Kieler, Nørgaard.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: This study was funded by the Swedish Pharmacy Company and by the authors' affiliations. Olof Stephansson was supported by a postdoctorate scholarship from the Swedish Society of Medicine.
Disclaimer: The Swedish Pharmacy Company was not involved in the design and conduct of the study; collection, management, analysis, or interpretation of the data; and preparation, review, or approval of the manuscript.
This article was corrected for errors on April 9, 2013.