Background: Many antihypertensive drugs are also used as migraine prophylactics, but the relationship between blood pressure and headache is not been well understood. The objective of the present study was to explore the association between blood pressure and headache prevalence, and the effect of antihypertensive medication on this relationship, using both cross-sectional and prospective data from a large population.
Methods: We used data from two large epidemiologic studies, the Nord-Trøndelag Health Survey 1984-1986 (HUNT-1) and 1995-97 (HUNT-2), to evaluate the association between blood pressure (systolic, diastolic, mean arterial, and pulse pressure) and migraine and nonmigrainous headache.
Results: Increasing systolic blood pressure was associated with decreasing prevalence of having nonmigrainous headache or migraine. The most consistent and robust finding, however, was that increasing pulse pressure was linked to decreased prevalence of both nonmigrainous headache and migraine, evident for both sexes in the prospective and cross-sectional analyses. In subjects using antihypertensive medication, this finding was less clear.
Conclusion: Both increased systolic blood pressure and pulse pressure are related to arterial stiffness and may decrease headache prevalence through modulation of the baroreflex arch, which in turn generates hypoalgesia. This is due to a phenomenon called hypertension-associated hypalgesia. Stimulation of the baroreflex arch in response to increased blood pressure is assumed to inhibit pain transmission at both spinal and supraspinal levels, possibly because of an interaction of the centers modulating nociception and cardiovascular reflexes in the brainstem.