Statistical analysis
All data were double entered by two specialist nurses. A third‐party statistician conducted all analyses. Per‐protocol (PP) analyses were performed by excluding the participants who dropped out of the study or failed to comply with the study protocol. The ITT analyses were performed using all participants according to their original grouping, regardless of whether they complied with the intervention protocol or not (e.g., missing at follow‐up assessments and dropouts). For the participants missing follow‐up assessments or dropped out, their last measurement during follow‐up was recorded as the data at the endpoint. SPSS 18.0 was used for data analysis. Continuous variables were presented as mean ± standard deviation (SD) or median and range, according to distribution, as determined by the Kolmogorov–Smirnov test. Group comparisons were performed by Student's 