CYP27A1 and breast cancer: The present meta-analysis has suggested that Taichi exercise may be effective in attenuating BMD loss (e.g., lumbar spine, proximal femur neck and trochanter, and total hip) and improving bone biomarkers (BAP and CTX: C-terminal telopeptide of type I collagen) in special populations, including middle-aged and older adults, perimenopausal and postmenopausal women, people with osteoarthritis, breast cancer survivors, and people with osteoporosis.