A Mechanistic Randomized Controlled Trial on the Cardiovascular Effect of Berberine

Objectives: to assess the effect of berberine on a set of well-established CVD risk factors, including lipids, systolic and diastolic blood pressure, coagulation factors, fasting glucose, insulin, adiposity (body mass index (BMI) and waist-hip ratio (WHR)) and the mediation via testosterone and/or sex hormone binding globulin using a mechanistic, parallel RCT. Study design: a mechanistic, randomized, double-blind, placebo-controlled, parallel trial in 84 Chinese men in Hong Kong. Interventions: the eligible participants will be randomized to take berberine (500 mg orally twice a day) or placebo for 12 weeks. Blood samples will be taken at baseline, 8-week and 12-week intervention. Data analysis and expected results: the investigators will use an intention to treat analysis, with multiple imputation for missing data. The investigators will compare the baseline characteristics of participants in the two arms using analysis of variance. The investigators will assess the effects of berberine on changes in CVD risk factors using analysis of variance, and the mediation using causal mediation analysis. Compared to the placebo group, the participants receiving berberine are expected to have lower burden of cardiovascular disease risk factors at the end of the intervention. These effects may be mediated or partly mediated by lowering testosterone.