Statistical analysis
Statistical analyses were done using SPSS software (version 16; SPSS Inc, Chicago, IL). The normality of the data distribution was assessed by the Kolmogorov–Smirnov test and descriptive indices. The results of quantitative data with normal and non-normal distribution are reported as mean ± SD and median (25th and 75th percentiles), respectively. Frequency (percent) is reported for qualitative data. Due to the non-normal distribution of irisin, logarithmic transformation was performed before the analysis. Comparison of baseline characteristics between the groups was done using the independent sample t-test, Mann–Whitney U test, and chi-squared test. To compare within-group changes before and after the intervention, the paired sample t-test and Wilcoxon signed-rank test were applied. The changes between the two groups after the intervention were compared by analysis of covariance adjusting for the baseline values and other potential confounders. Each variable’s percentage change was obtained by the following formula: [(after mean value - before mean value)/before mean value] 100. All analyses were carried out by the intention-to-treat principle, and 