An analysis of 6 studies found an increased risk of dementia for all causes among patients with any headache. However, no association between headache and Alzheimer's disease was found.
Dementia is the most common neurological disease in the elderly and in addition to trying to develop a drug treatment that could significantly delay the progression of the disease, the researchers also focused their efforts on identifying risk factors for dementia in hope that the incidence of dementia can be reduced by effectively preventing and controlling risk factors.
Currently, identified risk factors include obesity, diabetes, hypertension, lipid metabolism disorders, coronary artery disease and heart failure. Now, researchers have indicated that any headache is associated with an increased risk of dementia for all causes. However, the analysis of 6 studies out of 291,549 people found that migraine was not statistically significant associated with an increased risk of Alzheimer's disease.
Overall, the history of any headache was associated with an increased risk of dementia for all causes (relative risk [RR] = 1.24; 95% CI: 1.09-1.41), but there was a considerable heterogeneity between the studies. According to the researchers, neither the analysis of subgroups by sample size nor the design of the study could explain the reason behind the heterogeneity and a sensitivity analysis showed that none of the individual studies had a & # 39; clear influence on the size of the combined effect.
The association between headaches and dementia remains largely unknown, but several mechanisms have been hypothesized to be involved. Headache is a common pain disorder and previous research has found that different brain structures involved in the pain network undergo metamorphic changes during the disease process. The authors noted that these brain regions also play important roles in the memory network.
Another hypothesis comes from the relationship that there is an association of hyperintensity of white matter with an increased risk of dementia. "Incidentally, headaches are said to have an increased risk of white matter hyperintensity," wrote the researchers, who explained that subtle changes in white matter in the brain could help increase the risk of dementia in these patients.
Three of the 6 studies focused specifically on migraine and, after combining the effect of the condition, the researchers found a RR of 1.28 (95% CI: 0.64 to 2.54 ) for dementia for all causes. Only 1 study demonstrated an association between migraine and an increased risk of Alzheimer's disease, showing a RR of 4.22 (95% CI: 1.59-10.42).
"It should be noted that no statistically significant results were found in the aggregate analysis of the association between migraine and dementia for all causes," the researchers wrote. "However, the result of this analysis was based on only 3 studies and 2 were extracted, and as such, should be interpreted with caution."
They added that although current evidence available on migraine and dementia was poor, it could suggest that a possible association could exist and underscores the need for more population-based research on this association.
Wang J, Xu W, Sun S, Yu S, Fan L. Headache and the risk of dementia: a systematic review and meta-analysis of cohort studies [published online October 11, 2018]. J Headache pain. doi: 10.1186 / s10194-018-0925-4.