Author Contributions: Dr Michaëlsson 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: Sennerby, Melhus, Michaëlsson.
Acquisition of data: Melhus, Pedersen, Michaëlsson.
Analysis and interpretation of data: Sennerby, Melhus, Gedeborg, Byberg, Garmo, Ahlbom, Pedersen, Michaëlsson.
Drafting of the manuscript: Sennerby, Michaëlsson.
Critical revision of the manuscript for important intellectual content: Sennerby, Melhus, Gedeborg, Byberg, Garmo, Ahlbom, Pedersen, Michaëlsson.
Statistical analysis: Gedeborg, Byberg, Garmo, Ahlbom, Michaëlsson.
Obtained funding: Melhus, Pedersen, Michaëlsson.
Administrative, technical, or material support: Sennerby, Pedersen, Michaëlsson.
Study supervision: Pedersen, Michaëlsson.
Financial Disclosures: None reported.
Funding/Support: This work was supported by grant AG 08754 from the National Institutes of Health and another from the Swedish Research Council.
Role of the Sponsor: The funding organizations had no 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.