Ethics Approval and Informed Consent
All the participants provided written informed consent. The Research Ethics Review Board of the National Center for Health Statistics approved the NHANES III (https://www.cdc.gov/nchs/nhanes/irba98.htm). Data and materials produced by the US Centers for Disease Control and Prevention (CDC) are in the public domain and can be used without permission.
Acknowledgment
We wish to thank NHANES program for their effort on data collection and sharing. Yangang Wang and Hongwei Ji are senior authors.
Disclosure
The authors report no conflicts of interest in this work.