Author Contributions: Dr Dawe 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: Dawe, Cameron, Yule, Ibbotson, and Ferguson. Acquisition of data: Dawe, Cameron, Yule, and Ibbotson. Analysis and interpretation of data: Dawe, Ibbotson, Moseley, and Ferguson. Drafting of the manuscript: Dawe. Critical revision of the manuscript for important intellectual content: Dawe, Cameron, Yule, Ibbotson, Moseley, and Ferguson. Statistical analysis: Dawe. Administrative, technical, and material support: Moseley. Study supervision: Dawe, Ibbotson, and Ferguson.