**Contents** 1. **1-Participant-characteristics-analysis.Rmd** contains R code for all analysis reported in the paper. Results are saved in the files `Participant-characteristics-tables.Rdata` and `Participant-characteristics-plots.Rdata`. 2. **1-Participant-characteristics-analysis.html** is the compiled version of `Participant-characteristics-analysis.Rmd`. It can be viewed in a web browser. It includes all descriptive summaries, meta-analysis results, and plots. 3. **2-Participant-characteristics-tables.Rmd** contains R code for generating the formatted version of the results table in the paper. 4. **2-Participant-characteristics-tables.pdf** is the compiled version of `2-Participant-characteristics-tables.Rmd`. It contains the formatted results table included in the paper. 5. **3-Participant characteristics supplement.Rmd** contains R code for generating the formatted tables and figures reported in the supplementary materials of the paper. 6. **3-Participant characteristics supplement.pdf** is the compiled version of `3-Participant characteristics supplement.Rmd`. It contains the formatted tables and figures included in the supplementary materials of the paper. 7. **Participant-characteristics-tables.Rdata** contains tables of results created in `1-Participant-characteristics-analysis.Rmd`. 8. **Participant-characteristics-figures.Rdata** contains figures created in `1-Participant-characteristics-analysis.Rmd`.