The following is a summary of “Genetic evidence for the causal relationships between migraine, dementia, and longitudinal brain atrophy,” published in the June 2024 issue of Pain by Zhao et al.

While migraines share risk factors and brain changes with dementia, prior studies haven’t proven migraines cause dementia.

Researchers conducted a retrospective study using Mendelian randomization (MR) to explore if genes linked to migraine cause dementia and if brain structural changes play a mediating role.

They gathered genome-wide association study (GWAS) summary statistics for migraine, its subtypes, and four types of dementia (including Alzheimer’s disease (AD), vascular dementia, frontotemporal dementia, and Lewy body dementia). Additionally, GWAS summary statistics were obtained for 7 longitudinal brain measures reflecting structural changes. Using this data, Two-sample MR analyses were conducted to study migraine’s causal effects on dementia and brain structural changes. To investigate the potential mediation of brain structural changes between migraine and dementia, a two-step MR mediation analysis was performed.

The results showed a significant link between genetically predicted migraine and increased AD risk (OR = 1.097, 95% CI = [1.040, 1.158], P=7.03 × 10^-4). Additionally, migraine notably accelerated annual atrophy of the total cortical surface area (-65.588 cm² per year, 95% CI = [-103.112, -28.064], P=6.13 × 10^-3) and thalamic volume (-9.507 cm³ per year, 95% CI = [-15.512, -3.502], P=1.91 × 10^-3). Migraine without aura (MO) subtype elevated AD risk (OR = 1.091, 95% CI = [1.059, 1.123], P=6.95 × 10^-9) and hastened annual atrophy of the total cortical surface area (-31.401 cm² per year, 95% CI = [-43.990, -18.811], P=1.02 × 10^-6). The two-step MR mediation analysis showed that thalamic atrophy partially mediated migraine’s causal effect on AD, explaining 28.2% of the total effect.

Investigators concluded that MR showed migraine increases the risk of AD and pinpointed thalamus shrinkage over time as a possible contributing factor.

Source: thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-024-01801-7