Study design and setting
This study was based on a randomized, double-masked, placebo-controlled, and cross-over trial which comprised 2 phases in mainland China. The detailed design and methods have been described previously in phase 1 [The study adhered to the tenets of the Declaration of Helsinki and was approved by the Ethics Committee of Beijing Tongren Hospital. All participants provided written informed consent after agreeing to enrollment. The trial was registered on the Chinese Clinical Trial Registry (