Author Contributions
Conceived and designed the study: Desheng Zhai, Shi Wu Wen, Ravi
Retnakaran. Participated in data collection and analysis: Ying Zhao, Na
Wang, Mingcan Li, Yuan Yuan, Ruiling Zhang. Wrote the first draft of the
manuscript: Ying Zhao. All authors contributed to refinement of the
study protocol and contributed to, and approved, the final manuscript.
Author R. Zhang and D. Zhai have full access to all of the data in the
study and take responsibility for the integrity of the data and the
accuracy of the data analysis.