HealthDay News — Migraines have been linked to structural brain changes, particularly in the presence of aura, results of a meta-analysis show.
Migraineurs with aura had white matter brain lesions 68% more often than those without migraine; however, a trend for 34% elevated risk of white matter among migraine patients without aura did not reach significance, Asma Bashir, MD, of the Danish Headache Center at Glostrup Hospital in Copenhagen and colleagues reported in Neurology.
There was also a correlation between infarct-like abnormalities, brain volume changes and migraine, the researchers found, but the cause of such changes and whether they have any clinical significance remains unknown.
“Traditionally, migraine has been considered a benign disorder without long-term consequences for the brain,” the researchers noted.
The meta-analysis included data from six population-based studies and 13 clinic-based studies that evaluated MRI abnormalities in migraineurs from 1989 through 2013. The presence of white matter abnormalities ranged from 4% to 59% across studies.
A pooled analysis of the four studies that reported on white matter abnormalities showed migraine with aura increased the likelihood of such brain changes compared with no-migraine controls (odds ratio 1.68; 95% CI: 1.07-2.65). Odds of white matter lesions among patients with migraine without aura was 1.34 but was not statistically significant (95% CI: 0.96-1.87).
The likelihood for infarct-like brain lesions was 44% for migraineurs both with and without aura across two pooled studies (P=0.04), but the association was not statistically significant compared with controls.
Among the nine studies that examined brain volume, seven showed that migraineurs had reduced grey matter density compared with controls, and another study indicated increased grey matter density in the regions of the brain involved in pain processing among those with migraine and aura.
“Additional longitudinal studies are needed to determine the differential influence of migraine without and with aura, to better characterize the effects of attack frequency and to assess longitudinal changes in brain structure and function,” the researchers concluded.
In a second migraine study published in the same journal, Walter F. Stewart, PhD, from Sutter Health in Concord, Calif., and colleagues found the incidence rate of migraine is inversely related to household income, with prevalence increasing as household income decreased.
They analyzed data from 132,674 females and 124,665 males aged 12 years and older who participated in the American Migraine Prevalence and Prevention Study to examine whether the higher prevalence of migraine in lower household income groups is explained by a higher incidence rate or lower remission rate.
Migraine incidence is higher among lower household income groups, regardless of race and other confounding variables, but household income had no effect on migraine remission rates, the researchers found.
“The higher incidence of migraine in lower household income groups is compatible with the social causation hypothesis,” Stewart and colleagues write. “Once initiated, migraine remission is independent of household income.”