Spss statistics for macintosh software

Statistical analysis was performed using IBM SPSS Statistics software for Macintosh version 28.0.1.1 (Armonk, NY). Proportion comparison between categorical variables was performed using Fisher's exact test, the Fisher–Freeman–Halton exact test, or the Chi-squared test depending on the number of observations. Comparison between continuous variables was carried out using Mann–Whitney $U$ and Kruskal–Wallis tests (in the case of $>\mathrm{2}$ independent variables). Statistical significance was set at $p<\mathrm{0.05}$ . In case of multiple comparisons, a Bonferroni correction was applied.

Numeric and categorical variables were described as mean [standard deviation (SD)] and frequency (percentage), respectively. We adjusted the prevalence rate of RLS based on the real age and sex distribution of Tehran population according to the national census. Univariate comparisons between the RLS+ and RLS- groups were performed using independent samples t test, Mann-Whitney u test and Pearson Chi square test where appropriate (Table 1). Afterwards, multivariate binary logistic regression models with enter and forward conditional methods were performed with the following steps:
In order to investigate the risk of collinearity between the predictors, we calculated and reported tolerance index, which represents the proportion of variance for each predictor that is not explained by other predictors in the model. The risk for collinearity was considered low if tolerance was >0.4 for each variable in the model.
We used IBM SPSS Statistics for Macintosh software, version 22.0 for all analytical procedures. A two-tailed p-value of <0.05 was considered as the threshold for statistical significant differences or associations.