The epidemiological data on the prevalence of cluster headache are incomplete. Early data were collected by the Berlin internist and German headache pioneer von Heyck (1976). He assumed that 6% of the population suffers from migraines. Of these 6%, a third consult a doctor about headaches. Based on the information in his practice, he knew that there was about one patient with a cluster headache for every 50 migraine patients. From these numbers, Heyck calculated a prevalence of cluster headaches of around four patients per 10,000 people. Similar figures come from an Italian study in which the prevalence of cluster headaches was estimated based on consultation rates in specialized headache centers. It has been calculated that between one and four people out of 10,000 suffer from cluster headaches.
A single population-based study on the prevalence of cluster headache was conducted in San Marino by Benassi et al. (1986). In the small state's total population of 21,792 residents, there were 15 patients who met the criteria for cluster headache. This results in a prevalence of 0.07%. The transfer of the numbers to other countries should be carried out with caution due to the island situation of the state of San Marino, but overall it appears that one has to assume that there are fewer than one patient with cluster headache for every 1,000 people. This once again confirms the rarity of this form of headache.
Cultural differences
It is not yet sufficiently known whether there are cultural differences in the prevalence of cluster headaches. A Chinese study found extremely low prevalence figures for cluster headaches (0.006%). However, due to methodological peculiarities, the validity of this number must be assessed with caution. Other authors suggest that cluster headache is more common in the American black population than in the white population. Whether this is true has also not been empirically proven.
Gender differences
Various epidemiological studies (see above) provide clear and consistent evidence that cluster headache is the only form of primary headache disease with a clear predominance in men. The different information on the proportion of men within the group of patients with chronic and episodic cluster headaches is between 90% and 70%. However, more recent studies find smaller differences in frequencies between men and women of 3:1.