Classic yin and yang tonic formula for osteopenia: study protocol for a randomized controlled trial

We propose a multicenter double-blind randomized placebo-controlled trial to evaluate the efficacy and safety of the Classic Yin and Yang Tonic Formula for the treatment of osteopenia. Participants aged 55 to 75 with low bone mineral density (T-score between -1 and -2.5) and kidney deficiency in TCM will be included and randomly allocated into two groups: treatment group and control group. Participants in the treatment group will be treated with Classic Yin and Yang Tonic Granule, while the controlled group will receive placebo. Primary outcome measure will be BMD of the lumbar spine and proximal femur using dual-energy X-ray absorptiometry. Secondary outcomes will include pain intensity measured with visual analogue scales, quality of life, serum markers of bone metabolism, indices of Neuro-endocrino-immune network and safety.If the Classic Yin and Yang Tonic Formula can increase bone mass without adverse effects, it may be a novel strategy for the treatment of osteoporosis. Furthermore, the mechanism of the Chinese medical formula for osteoporosis will be partially elucidated.This study is registered at ClinicalTrials.gov, NCT01271647.Osteoporosis is a growing problem worldwide, with the greatest burden resulting from fractures. Nevertheless, the majority of fractures in adults occur in those with "osteopenia" (bone mineral density (BMD) only moderately lower than young normal individuals). Thus, there has been an interest in developing approaches to prevent bone loss. The agents currently approved for treatment and/or prevention of osteopenia include bisphosphonates, hormone replacement therapy with estrogen or combination estrogen/progesterone preparations, calcitonin, raloxifene, and parathyroid hormone as well. But short- and long-term consequences (adverse effects) of these therapies continue to be discovered. The adverse outcomes include cancer, and cardiac, dermatologic, gastrointestinal, gynecologic, immunologic, metabolic, musculoskeletal, neurological, p