Significant differences have been reported between men and women with cluster headache. These sex differences should be taken into consideration at the time of diagnosis and when selecting treatment options. These are the findings of a population-based, questionnaire study conducted in Sweden and published in the journal Neurology.
Researchers sought to describe sex differences in patient demographics, clinical phenotype, treatment, lifestyle, triggers, and chronobiology in a Swedish cluster headache population. Although it has been recognized that cluster headache is considered a male-dominated disorder, it has previously been suggested that females may exhibit a more severe phenotype.
Study participants were diagnosed with cluster headache and subtype by neurologists via the use of structured interviews and clinical interviews, based on criteria of the International Classification of Headache Disorders (ICHD), 3rd edition. All study participants were identified by the screening of medical records between 2014 and 2020, which were requested from hospitals and neurology clinics in Sweden for the International Classification of Diseases (ICD) 10 code G44.0 for cluster headache.
Each of the participants answered a detailed questionnaire with 3 parts, comprising both a checklist and free text items: (1) personal, demographic, and medical information; (2) questions designed to evaluate different aspects of cluster headache; and (3) questions associated with lifestyle.
Currently, among 1484 individuals who have been recruited for inclusion in the Swedish cluster headache biobank, 874 participated in this questionnaire study. Overall, 65.8% (575 of 874) of the participants were men and 34.2% (299 of 874) of them were women. When responding to the questionnaire, 186 of the participants reported to be experiencing a current cluster bout.
Age at the time of questionnaire completion differed slightly between men and women (51.3±13.9 years vs 49.0±15.0 years, respectively; P =.028). Men and women participants did not differ in age at the onset of cluster headache; however, a significantly lower percentage of men compared with women with cluster headache onset at <20 years of age was observed (16.2% vs 23.0%, respectively; odds ratio [OR], 0.64; 95% CI, 0.44-0.92; P =.020).
The researchers found that women were diagnosed with the chronic cluster headache subtype to a significantly greater extent than men (18% vs 9%, respectively; P =.0002). Additionally, women participants reported significantly longer bouts of cluster headache compared with men participants (P =.003) and used prophylactic therapies more often than men (60% vs 48%, respectively; P =.0005). In terms of associated symptoms, women compared with men experienced ptosis (61% vs 47%, respectively; P =.0002) and restlessness significantly more frequently (54% vs 46%, respectively; P =.02).
Further, more women than men reported a positive family history of cluster headache (15 vs 7%, respectively; P =.0002). Women participants also reported diurnal rhythmicity of their attacks more frequently than did men participants (74% vs 63%, respectively; P =.002). Alcohol as a trigger of cluster headache was observed more often in men compared with women (54% vs 48%, respectively; P =01), whereas lack of sleep triggering an attack was more common among women than men (31% vs 20%, respectively; P =.001).
Several limitations of the study warrant mention. All data were self-reported, which may introduce recall bias related to such variables as medication and whether a participant was in or out of a bout. Further, the study did not take into account individuals whose biological sexual characteristics and self-reported sex were not synonymous. Thus, sex bias in diagnosis might possibly contribute to the observed differences in severity.
“The data suggest that females generally may be more gravely affected by cluster headache than males,” the researchers noted. They concluded, “It is therefore of utmost importance for physicians to be aware of these sex differences when working in the clinic and meeting headache patients to be able to give the most effective treatment as fast as possible.”
Fourier C, Ran C, Steinberg A, Sjöstrand C, Waldenlind E, Belin AC. Sex differences in clinical features, treatment, and lifestyle factors in patients with cluster headache. Neurology. Published online December 21, 2022. doi:10.1212/WNL.0000000000201688