Xi et al. [13] revealed that EGCG also notably induced cyclin D1, β-catenin and Wnt protein expression in mice with secondary osteoporosis, and inhibited peroxisome proliferator-activated receptor γ protein expression; in general, EGCG showed a protective effect on a mouse model of secondary osteoporosis through the Wnt/β-catenin signaling pathway. This evidence concerns the gene CCND1 and osteoporosis.