A randomized, prospective study of the effects of Tai Chi Chun exercise on bone mineral density in postmenopausal women

Objective: To evaluate the potential benefits of programmed Tai Chi Chun (TCC) exercise on the weight-bearing bones of early postmenopausal women. Design: Age-matched and randomized prospective intervention. Setting: University medical school. Participants: One hundred thirty-two healthy postmenopausal women (mean age, 54.+/-3.5y) within 10 years of menopause onset were recruited and randomized into the TCC exercise group (n=67) or the sedentary control group (n=65). Intervention: Supervised TCC exercise was performed by the TCC group for 45 minutes a day, 5 days a week, for 12 months; control subjects retained a sedentary life style. Main Outcome Measures: Bone mineral density (BMD) was measured in the lumbar spine and proximal femur by using dual-energy x-ray absorptiometry and in the distal tibia by using multislice peripheral quantitative computed tomography (pQCT). All BMD measurements were repeated after 12 months in both groups. Fracture rate was also documented. Results: Baseline measurements showed homogeneity in age, anthropometric variables, and menstruation status between the TCC and control groups. Exactly 81.6% of the subjects in the TCC group and 83.1% of subjects in the control group completed the 12-month follow-up study. BMD measurements revealed a general bone loss in both TCC and sedentary control subjects at all measured skeletal sites, but with a reportedly slower rate in the TCC group. A significant 2.6- to 3.6-fold retardation of bone loss (P<.01) was found in both trabecular and cortical compartments of the distal tibia in the TCC group as compared with the controls, as measured by pQCT. A total of 4 fracture cases were documented during follow-up, including 3 subjects in the control group and I in the TCC group. Conclusions: This is the first prospective and randomized study to show that a programmed TCC exercise intervention is beneficial for retarding bone loss in weight-bearing bones in early postmenopausal women. Long-term follow-up is needed to substantiate the role of TCC exercise in the prevention of osteoporosis and its related fracture.