Author Contributions:Study concept and design: Shete, Bondy, and Houlston. Acquisition of data: Liu, Robertson, and Bondy. Analysis and interpretation of data: Liu, Shete, and Hosking. Drafting of the manuscript: Liu, Bondy, and Houlston. Critical revision of the manuscript for important intellectual content: Shete, Hosking, Robertson, and Bondy. Statistical analysis: Liu, Hosking, and Bondy. Obtained funding: Bondy. Administrative, technical, and material support: Robertson, Bondy, and Houlston. Study supervision: Shete and Bondy.