Abstract
In order to investigate the comorbidity of migraine and headache associated with sexual activity (HSA), we performed a case-control study based on migraine patients. By means of a questionnaire and a personal interview, 100 migraine patients and 100 control subjects were examined regarding a diagnosis of HSA. In five subjects from the migraine group vs. none from the control group, a diagnosis of HSA could be established (P = 0.021). Previous studies that have demonstrated comorbidity of migraine and HSA were all based on HSA patients. Thus, it can now be concluded that the association between the two headache disorders is bilateral. In addition, the prevalence of HSA in the general population can be estimated to average around at least 0.9%, which concurs with previously published data.
Introduction
Migraine and ‘headache associated with sexual activity’ (HSA) both belong to the group of primary headache disorders as classified by the International Headache Society (IHS). HSA is a headache that is precipitated by sexual activity, with two clinically different subtypes. Type 1 is preorgasmic headache and is described as a dull ache that occurs during sexual activity and increases with sexual excitement. The second type is orgasmic headache, which resembles a sudden severe headache, occurring at orgasm (1).
The comorbidity of migraine and HSA has mainly been investigated from the perspective of HSA patients. Until 1986, 110 cases of HSA had been published, of which 23% had a positive history of migraine (2). In clinical studies, even higher prevalence rates of migraine in HSA patients have been determined, ranging from 25% to 47% (3–5).
The purpose of this study was to investigate the comorbidity of migraine and HSA from the other perspective, i.e. with a case–control study based on migraine patients.
Methods
We included 100 consecutive patients with a diagnosis of migraine with and/or without aura according to the IHS diagnostic criteria who were willing to answer a questionnaire on headaches related to sexual activity. Subjects were recruited from our supraregional headache out-patient clinic. One hundred age- and sex-matched persons who did not suffer from migraine were also enrolled as a control group for this case–control study (staff members and waiting relatives). All subjects were given questionnaires, including a screening question: if the subject had ever suffered from headache in relation to sexual excitement or sexual activity. Persons who answered yes were personally interviewed to give more details about this headache to enable the diagnosis according to the IHS diagnostic criteria to be established and to determine the HSA subtype.
χ2 test (Fisher's exact test, if applicable) was used for statistical analysis. P-values <0.05 were considered to be significant.
Results
Ninety-six migraine patients answered the questionnaire concerning HSA and four refused to answer any further questions regarding this subject. Of the 96 patients who answered the questions, 83 were female and 13 male. Seventy-two subjects suffered from migraine without aura, 24 from migraine with (and without) aura. In five migraine patients a diagnosis of HSA could be established (two female, three male). All were classified as HSA type 2, i.e. orgasmic headache. Of the 100 control subjects who answered the questionnaire, 87 were female and 13 were male. None of the control subjects indicated that they suffered from HSA. The different data in the migraine and control group are listed in Table 1. The difference in HSA prevalence between migraine patients and control subjects was statistically significant (P = 0.021). In addition, the difference between HSA prevalence in male vs. female migraine patients was also significant (P = 0.002). All patients with HSA had migraine without aura, although there was no significant difference compared with the lack of HSA patients with migraine with aura (P = 0.229).
Epidemiological data of migraine patients and control subjects.
Statistical comparison by χ2 test, Fisher's exact test, if applicable, and Mann–Whitney-U-test.
Discussion
To our knowledge, this is the first case–control study to be based on migraine patients and it shows a significant association between migraine and HSA. Other publications to show such a comorbidity were based on HSA patients (2–5). With this study, it can now be concluded that the association is not only unilateral but bilateral.
In addition to the studies that have demonstrated an epidemiological association, some authors have suggested a clinical or pathophysiological relationship between the two headache disorders. In a study on the clinical course of HSA, it was noticed that the presence of concomitant migraine or tension-type headache was significantly associated with the recurrence of periods lasting weeks to months in which HSA occurred, whereas subjects without another primary headache disorder more often suffered from only one HSA period or episode (6).
From the therapeutic perspective, propranolol has been shown to be effective in the prophylaxis of HSA (2) and is also one of the first-line medications in the prophylaxis of migraine (7).
Regarding a possible pathophysiological relationship between the disorders, it has been shown that HSA patients as well as migraine patients have a loss of cognitive habituation as measured by visual event-related potentials (8).
We did not observe any migraine patient with both aura and HSA. However, previous studies had shown that migraine aura does not exclude the presence of HSA (3).
There are scant data on the prevalence of HSA in the general population. In the only population-based epidemiological survey, the lifetime prevalence for HSA was 1% (9). In our sample of migraine patients, approximately 5% suffered from HSA. In a meta-analysis of the lifetime prevalence of migraine in Europe figures vary from 12% to 27.5%, with a mean of 18.5% (10). Based on these data, the prevalence of HSA in the general population can be estimated to average around 0.9%, which is close to the prevalence given by Rasmussen and Olesen (9). Thus, our study confirms the prevalence of HSA in the general population to be around 1% and that it is significantly greater in men than in women. However, this estimate remains very uncertain, because we considered only our sample of migraine patients. It might also be that there exists a selection bias in our sample, with patients not reporting sexual headaches. Thus, the true prevalence of HSA in migraine could even be higher.