Green Tea and Tai Chi for Bone Health

This is a 24-week, randomized, and placebo-controlled intervention trial to investigate the effects of green tea polyphenols (GTP) and Tai Chi (TC) on relevant primary and secondary endpoints in postmenopausal women with osteopenia. Women at least 2 years after menopause, with osteopenia, will be recruited primarily from local senior independent/assisted living facilities, municipal senior community centers, and obstetrics and gynecology clinics. After screening, qualified participants will be matched for age and will be randomly assigned to one of the four treatment groups: placebo, GTP, placebo+TC, and GTP+TC. During the 24-week intervention, all participants will be provided with calcium and vitamin D daily. The participants in the placebo group will receive medicinal starch for 24 weeks. The GTP participants will receive GTP for 24 weeks. The placebo+TC participants will receive both placebo and TC treatments for 24 weeks. The GTP+TC participants will receive both GTP and TC treatments for 24 weeks. Participants will receive the primary and secondary outcome measures at baseline, 4, 12, and 24 weeks. The primary outcome measures are concentrations of bone biomarkers. The secondary outcome measure is a biomarker of oxidative stress DNA damage. Additional secondary outcome is muscle strength/physical function. Investigators evaluating the endpoints will be blinded to intervention allocation.