Arterial hypertension and migraine: comorbidity or something else?

Several studies on patients observed in headache centers show an association between headache, including migraine, and arterial hypertension. As both these pathologies have an elevated prevalence in the general population, their association in the same patient could be casual and does not indicate a real comorbidity. Recent studies undertaken on the general population show results that seem to exclude a comorbidity between the two pathologies. Basal elevated diastolic and systolic pressures are not associated to the emergence of a migraine, whereas for subjects with systolic pressure over 150 mmHg, the risk of developing a nonmigrainous headache is less than 30% compared with normotensive subjects. However, other recent studies suggest that the association between arterial hypertension and migraine consists in the sharing of genetic abnormalities involving the angiotensin-converting enzyme (ACE): a greater availability of angiotensin II, due to a higher activity of ACE, seems to be a pathogenetic mechanism common to arterial hypertension and migraine. The possible pathogenetic role of ACE in migraine and in other headaches seems to be confirmed by several clinical studies that show the efficacy of drugs that inhibit ACE or block angiotensin II receptor. Recent prospective studies have evaluated risk factors for the chronicity of episodic migraine and have shown that arterial hypertension appears to play an important role because a higher incidence of this disease has been observed in patients with episodic migraine transformed into chronic type.