FIGURE 2.

Scatter plots of the association between years of schooling, vitamin B12, and stress and migraine without aura. IVW, inverse variance weighted; MR, Mendelian randomization; SNP, single nucleotide polymorphisms. Annotation: Scatter plots of the migraine-SNP associations (y-axis) versus the exposures-SNP associations (x-axis) were shown, with vertical and horizontal lines showing 95% confidence intervals. The fitted curves among the dots refer to the differential statistical analysis methods. The MR analyses were performed with the inverse variance weighted method, the MR-Egger method, the weighted median method, and the IVW radial method. (A) shows the scatter plot for years of schooling, (B) shows the level of vitamin B12, and (C) shows the stress owing to financial difficulties.