Author Contributions: Dr R. Chen has 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: R. Chen. Acquisition of data: R. Chen and Hu. Analysis and interpretation of data: R. Chen, Zhang, Y. Chen, Hu, and Wilson. Drafting of the manuscript: R. Chen. Critical revision of the manuscript for important intellectual content: Zhang, Y. Chen, Hu, and Wilson. Statistical analysis: R. Chen and Zhang. Obtained funding: R. Chen. Administrative, technical, and material support: Zhang and Hu. Study supervision: R. Chen, Y. Chen, Hu, and Wilson.
Financial Disclosure: None reported.
Funding/Support: This study was funded by research grants from the Alzheimer's Research Trust and the BUPA Foundation, United Kingdom. With support from the Strategic Research Development Fund at the University of Wolverhampton, Dr Zhang visited the United Kingdom to carry out postdoctoral research under the supervision of Dr R. Chen.
Role of the Sponsors: The sponsors of the study had no role in study design, data analysis, data interpretation, or writing of the report.
Disclaimer: The opinions expressed in this report are not necessarily those of the funders.
Additional Contributions: We thank the participants and all who were involved in the survey in the 4-province study.