Effects of Tai Chi or Conventional Exercise on Central Obesity in Middle-Aged and Older Adults : A Three-Group Randomized Controlled Trial Author: Parco M Siu1, Angus P Yu1, Edwin C Chin1, Doris S Yu1, Stanley S Hui2, Jean Woo2, Daniel Y Fong1, Gao X Wei3, Michael R Irwin4 Affiliation: <sup>1</sup> The University of Hong Kong, Pokfulam, Hong Kong, China (P.M.S., A.P.Y., E.C.C., D.S.Y., D.Y.F.). <sup>2</sup> The Chinese University of Hong Kong, Shatin, Hong Kong, China (S.S.H., J.W.). <sup>3</sup> Chinese Academy of Sciences, Beijing, China (G.X.W.). <sup>4</sup> University of California, Los Angeles, Los Angeles, California (M.R.I.). Conference/Journal: Ann Intern Med Date published: 2021 Jun 1 Other: Special Notes: doi: 10.7326/M20-7014. , Word Count: 301 Background: Central obesity is a major manifestation of metabolic syndrome, which is a common health problem in middle-aged and older adults. Objective: To examine the therapeutic efficacy of tai chi for management of central obesity. Design: Randomized, controlled, assessor-blinded trial. (ClinicalTrials.gov: NCT03107741). Setting: A single research site in Hong Kong between 27 February 2016 and 28 February 2019. Participants: Adults aged 50 years or older with central obesity. Intervention: 543 participants were randomly assigned in a 1:1:1 ratio to a control group with no exercise intervention (n = 181), conventional exercise consisting of aerobic exercise and strength training (EX group) (n = 181), and a tai chi group (TC group) (n = 181). Interventions lasted 12 weeks. Measurements: Outcomes were assessed at baseline, week 12, and week 38. The primary outcome was waist circumference (WC). Secondary outcomes were body weight; body mass index; high-density lipoprotein cholesterol (HDL-C), triglyceride, and fasting plasma glucose levels; blood pressure; and incidence of remission of central obesity. Results: The adjusted mean difference in WC from baseline to week 12 in the control group was 0.8 cm (95% CI, -4.1 to 5.7 cm). Both intervention groups showed reductions in WC relative to control (adjusted mean differences: TC group vs. control, -1.8 cm [CI, -2.3 to -1.4 cm]; P < 0.001; EX group vs. control: -1.3 cm [CI, -1.8 to -0.9 cm]; P < 0.001); both intervention groups also showed reductions in body weight (P < 0.05) and attenuation of the decrease in HDL-C level relative to the control group. The favorable changes in WC and body weight were maintained in both the TC and EX groups, whereas the beneficial effect on HDL-C was only maintained in the TC group at week 38. Limitations: High attrition and no dietary intervention. Conclusion: Tai chi is an effective approach to reduce WC in adults with central obesity aged 50 years or older. Primary funding source: Health and Medical Research Fund. PMID: 34058100 DOI: 10.7326/M20-7014