Author Contributions: Dr Greene 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. Drs Gadalla and Lund contributed equally to this study.
Study concept and design: Gadalla, Lund, Pfeiffer, Mueller, Moxley, Kristinsson, Hilbert, Landgren, Melbye, Greene.
Acquisition of data: Gadalla, Lund, Kristinsson, Greene.
Analysis and interpretation of data: Gadalla, Lund, Pfeiffer, Gørtz, Mueller, Moxley, Kristinsson, Bjorkholm, Shebl, Hilbert, Landgren, Wohlfahrt, Melbye, Greene.
Drafting of the manuscript: Gadalla, Lund, Pfeiffer, Mueller, Landgren, Greene.
Critical revision of the manuscript for important intellectual content: Gadalla, Lund, Gørtz, Mueller, Moxley, Kristinsson, Bjorkholm, Shebl, Hilbert, Landgren, Wohlfahrt, Melbye, Greene.
Statistical analysis: Gadalla, Pfeiffer, Gørtz, Shebl, Landgren.
Obtained funding: Greene.
Administrative, technical, or material support: Gadalla, Lund, Mueller, Kristinsson, Bjorkholm, Hilbert, Melbye, Greene.
Study supervision: Moxley, Bjorkholm, Wohlfahrt, Melbye, Greene.
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 research was supported by grants from the Swedish Cancer Society, Stockholm County Council, Karolinska Institutet Foundations, Danish Medical Research Council, Intramural Research Program of the US National Cancer Institute (including contract N02CP31003-3 to Westat), University of Rochester Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center (NIH/U54/NS048843), National Registry of Myotonic Dystrophy and Facioscapulohumeral Muscular Dystrophy Patients and Family Members (NIH/N01-AR-50-227450), and Clinical and Translational Science Institute and Clinical Research Center (NIH UL1 RR024160; National Center for Research Resources).
Role of the Sponsor:The funding agencies had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.
Additional Contributions: We thank Shiva Ayobi, National Board of Health and Welfare, Stockholm, Sweden, and Emily Steplowski, BS, and Joseph Barker, BS, Information Management Services, Silver Spring, Maryland, for important contributions to the development of this database; Gerda Engholm, CandStat, and Hans Storm, MD, Danish Cancer Society, for their valuable advice on combining the Danish and Swedish cancer data; and Margaret A. Tucker, MD, Human Genetics Program, National Cancer Institute, for her critical review of the manuscript and her valuable comments. None of the individuals received compensation for their contributions.