Fig. 2.

The forest plot compares the risk of fatigue (upper panel) and headache (lower panel) between females and males across various studies. Each square represents the RR for a study, with square size indicating the study’s weight in the analysis. Horizontal lines through squares denote the 95% CI. The diamond at the bottom shows the overall pooled RR and its 95% CI, summarizing the combined effect size. A vertical line at RR = 1 indicates no difference in risk between groups. Heterogeneity measures assess variability among study results.