Author Contributions: Dr Van Someren 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: Riemersma-van der Lek, Swaab, Hoogendijk, Van Someren.
Acquisition of data: Riemersma-van der Lek, Hol, Van Someren.
Analysis and interpretation of data: Riemersma-van der Lek, Swaab, Twisk, Hol, Van Someren.
Drafting of the manuscript: Riemersma-van der Lek, Hol, Van Someren.
Critical revision of the manuscript for important intellectual content: Riemersma-van der Lek, Swaab, Twisk, Hol, Hoogendijk, Van Someren.
Statistical analysis: Twisk, Van Someren.
Obtained funding: Riemersma-van der Lek, Swaab, Van Someren.
Administrative, technical, or material support: Swaab, Hol, Hoogendijk, Van Someren.
Study supervision: Swaab, Hoogendijk, Van Someren.
Financial Disclosures: None reported.
Funding/Support: Financial and material support were provided by the Netherlands Organization for Health Research, the Hague, by grants 0028-300-30 and 907-00-012; the Netherlands Organisation for Scientific Research, the Hague, by grants 016.025.041 and 051.04.010; the Stichting De Drie Lichten, Leiden; Stichting RVVZ; Zeist by grant 01-220; Japan Foundation for Aging and Health; Hersenstichting Nederland by grant 11F04-2.47; Internationale Stichting Alzheimer Onderzoek by grant 05511. Philips Lighting BV, Braun, and Cambridge Neurotechnology supplied material for this study at reduced cost.
Role of the Sponsor: None of the sponsors or funders had any involvement in the design or conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review or approval of the manuscript.
Additional Contributions: We thank the inhabitants and staff of the participating homes for the elderly. Renske van Hutten, MSc, Annemarie Kalis, MSc, and Rene den Haan, MSc, provided neuropsychological assessments, Jacqueline Sluijs, BSc, provided the assessment of the apolipoprotein E genotype, Joop van Heerikhuize, BSc, participated in the randomization and distribution of tablets, Jenneke Kruisbrink, PhD, provided library assistance, and Tini Eikelboom, MSc, and Wilma Verweij, MSc, corrected the English spelling and grammar; all are from the Netherlands Institute for Neuroscience, Amsterdam. The following persons provided advice on the protocol: Marcel Smits, MD, PhD (Centre for Sleep-Wake disorders and Chronobiology, Hospital Gelderse Vallei, Ede, the Netherlands) and Elsbeth Nagtegaal, PhD (Meander Medical Center, Department of Pharmacy, Amersfoort, the Netherlands). The following persons provided advice on multilevel analysis: Hans Berkhof, PhD (Department of Clinical Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, the Netherlands) and Min Yang, PhD (Centre for Statistics at Queen Mary University of London, London, England). Debra Skene, PhD (Neuroendocrinology Research Group, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, England) provided critical reading of the manuscript and useful comments. None of the acknowledged persons received any compensation.