Age-Related Changes in Headache Days across the Cognitive Spectrum

Is headache a risk factor for dementia? A systematic review and meta-analysis

OBJECTIVE

In this systematic review and meta-analysis, we critically evaluate available evidence regarding the association between primary headaches and subsequent decline of cognitive function and dementia.

BACKGROUND

Recent studies suggested that headache disorders may increase the risk for dementia. However, available studies are conflicting.

METHODS

To identify qualifying studies, we searched scientific databases, including Pubmed, Scopus, Web of Science, Science Direct and BMC, screening for relevant papers. In order to reduce the heterogeneity between different studies, the analyses were further subdivided according to the clinical diagnoses and the study methodologies.

RESULTS

We identified 23 studies investigating the association between primary headaches and the risk of dementia. Of these, 18 met our inclusion criteria for meta-analysis (covering 924.140 individuals). Overall effect-size shows that primary headaches were associated with a small increase in dementia risk (OR = 1,15; CI 95%: 1,03-1,28; p = 0,02). Analyzing subgroups, we found that migraine was associated with both a moderate increased risk of all-cause dementia (OR = 1,26; p = 0,00; 95% CI: 1,13-1,40) as well as a moderate increased risk of Alzheimer's disease (OR = 2,00; p = 0,00; 95% CI: 1,46-2,75). This association was significant in both case-control and retrospective cohort studies but not in prospective studies.

CONCLUSIONS

Our study supports the presence of a link between primary headaches and dementia. However, in the subgroup analysis, only patients with migraine showed a moderate increase risk for all-cause dementia and for Alzheimer's disease. Additional rigorous studies are needed to elucidate the possible role of primary headaches on the risk of developing cognitive impairment and dementia.

Different Aspects of Aging in Migraine

Migraine is a common neurological disease displaying an unusual dependence on age. For most patients, the peak intensity of migraine headaches occurs in 20s and lasts until 40s, but then headache attacks become less intense, occur less frequently and the disease is more responsive to therapy. This relationship is valid in both females and males, although the prevalence of migraine in the former is 2-4 times greater than the latter. Recent concepts present migraine not only as a pathological event, but rather as a part of evolutionary adaptive response to protect organism against consequences of stress-induced brain energy deficit. However, these concepts do not fully explain that unusual dependence of migraine prevalence on age. Many aspects of aging, both molecular/cellular and social/cognitive, are interwound in migraine pathogenesis, but they neither explain why only some persons are affected by migraine, nor suggest any causal relationship. In this narrative/hypothesis review we present information on associations of migraine with chronological aging, brain aging, cellular senescence, stem cell exhaustion as well as social, cognitive, epigenetic, and metabolic aging. We also underline the role of oxidative stress in these associations. We hypothesize that migraine affects only individuals who have inborn, genetic/epigenetic, or acquired (traumas, shocks or complexes) migraine predispositions. These predispositions weakly depend on age and affected individuals are more prone to migraine triggers than others. Although the triggers can be related to many aspects of aging, social aging may play a particularly important role as the prevalence of its associated stress has a similar age-dependence as the prevalence of migraine. Moreover, social aging was shown to be associated with oxidative stress, important in many aspects of aging. In perspective, molecular mechanisms underlying social aging should be further explored and related to migraine with a closer association with migraine predisposition and difference in prevalence by sex.

Is there a link between headache and cognitive disorders? A systematic review

BACKGROUND

The overall prevalence of headaches decreases with age; however headaches remain frequent in aged individuals who are also affected by other disorders such as cognitive decline. Despite the high frequency of both conditions in these persons, the association between headaches and cognitive decline is underexplored, underdiagnosed and poorly understood.

OBJECTIVE

In the present article, we aim to provide a comprehensive review of existing data concerning the link between headache and cognitive decline.

METHODS

We undertook a systematic literature review to report articles that focus on headaches (including all types of headaches) and neurocognitive disorders of degenerative causes.

RESULTS

Only 9 studies have explored the association between headaches and neurocognitive decline. Methods were highly variable from population-based study to short series of patients using either database or questionnaire during consultation. Studies focusing on Familial Alzheimer's Disease revealed a very high prevalence of headaches in mutation carrier patients compared to non-carrier patients.

CONCLUSION

The association between headaches and cognitive decline is underexplored. Future studies are needed to address the pathophysiological mechanisms to improve the treatment of these underestimated headaches.