Use of complementary health approaches among children aged 4-17 years in the United States: national health interview survey, 2007-2012

This report presents national estimates of the use of complementary health approaches among children aged 4-17 years in the United States.
... tai chi, or qi gong were the most commonly used complementary health approaches in both 2007 and 2012. 

Effects of Tai Chi on exercise capacity and health-related quality of life in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis

Tai Chi is a traditional Chinese mind-body exercise that has been widely practiced in the People's Republic of China for many centuries. This exercise has also been applied as a training modality in pulmonary rehabilitation programs for stable chronic obstructive pulmonary disease (COPD). 

Preliminary evidence suggests that Tai Chi has beneficial effects on exercise capacity and HRQoL in COPD patients. This exercise can be recommended as an effective alternative training modality in pulmonary rehabilitation programs.

Health benefits of qigong or tai chi for cancer patients: a systematic review and meta-analyses

Mind-body interventions are widely used by cancer patients to reduce symptoms and cope better with disease- and treatment-related symptoms. 
In the last decade, many clinical controlled trials of qigong/tai chi as a cancer treatment have emerged. This study aimed to quantitatively evaluate the effects of qigong/tai chi on the health-related outcomes of cancer patients.

The effects of mind-body therapies on the immune system: meta-analysis

Mind-body therapies reduce markers of inflammation and influence virus-specific immune responses to vaccination despite minimal evidence suggesting effects on resting anti-viral or enumerative measures.