Author Contributions: Dr Cnattingius 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: Cnattingius, Ekbom, Granath, Lambe.
Acquisition of data: Cnattingius, Lambe.
Analysis and interpretation of data: Cnattingius, Torrång, Ekbom, Granath, Petersson, Lambe.
Drafting of the manuscript: Cnattingius.
Critical revision of the manuscript for important intellectual content: Torrång, Ekbom, Granath, Petersson, Lambe.
Statistical analysis: Torrång, Granath, Petersson.
Obtained funding: Cnattingius, Ekbom, Granath, Lambe.
Administrative, technical, or material support: Cnattingius, Petersson, Lambe.
Study supervision: Cnattingius.
Financial Disclosures: None reported.
Funding/Support: This study was financially supported through a grant from the US Army Breast Cancer Research Program (DAMD 17-03-01-0741).
Role of the Sponsor: The US Department of Defense Breast Cancer Research Program had no role in, or control over, study design, collection, analysis, interpretation of data, or the writing of this report.
Acknowledgment: We thank Lorelei A. Mucci, ScD, Department of Epidemiology, Harvard School of Public Health, Boston, Mass, for providing invaluable comments to the manuscript.