Gritty images, harsh messages. A woman vomiting blood, a couple in front of a child’s coffin, a man languishing in an operating room, another with a hole in his neck… From the original “Smoking kills” printed on tobacco packets in 2003, it has passed to more specific slogans: “Smoking damages the lungs”, “Smoking can kill the unborn child”, “Smoking causes heart attacks”, “Smoking causes neck and throat cancer”, “Tobacco smoke contains more than 70 carcinogenic substances” … Cigarette smoking is associated with cancer, cardiovascular problems and, ultimately, death, but there is still more. An international genetic study, in which the Vall d’Hebron hospital has participated, concludes that smoking is one of the causes of cluster headache, one of the most intense pains that exists.
The photograph of a person upset by an extreme headache, with the slogan “Smoking causes cluster headaches” could be the new warning to raise awareness among smokers. Multiple factors influence the development of this disease, but tobacco plays a determining role, according to a genetic study aimed at finding the causes. Based on genetic data from 4,777 cluster headache patients and a further 31,575 healthy people, mostly from Europe and East Asia, the work has located eight genome regions associated with cluster headache risk, some of which show that the tobacco plays a key role.
The relationship was clearly suspected, considering that approximately 80% of people with cluster headaches are smokers or have been exposed to tobacco smoke from their parents during childhood. The work promoted by the International Cluster Headache Genetics Consortium, in which 13 countries participate, has confirmed this. Published in the Annals of Neurology , the study proves the cause-effect relationship between smoking and an excruciatingly painful and disabling pathology, also known as the pain of suicide. Although the mechanisms are not known in detail, the researchers indicate that tobacco affects the expression of some genes related to the development of headache. For example, smoking increases the expression of the MERTK gene and decreases that of CFTR, alterations that are also observed in patients with cluster headaches.
According to Patricia Pozo-Rosich, section head of the Neurology service and the Headache unit at the Vall d’Hebron hospital, the finding represents yet another incentive for smokers to decide to take the plunge. “We have considered that it was worth communicating the results because they represent one more reason to quit smoking and that people are aware that tobacco [causing 8 million deaths a year in the world, according to the WHO] not only causes cancer and facilitates cardiovascular disease, but for a person with a genetic risk of having cluster headaches it is the most important causal factor”, explains the doctor, head of the Headache and Neurological Pain group at the Vall d’Hebron Research Institute (VHIR).
Quitting smoking is a disease-modifying factor, says Pozo-Rosich. Patients who do, improve, and for nonsmokers (the minority), “control and management of the disease is more feasible.”
In addition to the role of tobacco, researchers have also analyzed the genetic relationship of cluster headaches with pathologies such as depression, attention deficit hyperactivity disorder (ADHD), defiant behaviour, migraine or musculoskeletal pain.
Cluster headache is an extraordinarily disabling disease, a primary headache originating from a genetic predisposition associated with lifestyle (smoking). It is considered a rare disease, with a prevalence of 0.1% of the adult population, and mainly affects men (three men for every woman), especially smokers, although not in all cases. “Many times the impact of hormones at the beginning of puberty triggers the development of the disease,” says Pozo-Rosich.
“It is called a cluster because it occurs with episodes that are grouped at certain times of the year. They last between half an hour and two hours and you can have between one and eight episodes a day, between three weeks and three months. In some people it becomes chronic. The episodes occur mostly at night, waking the person up, and if it is called suicide pain, it is because it is extraordinarily intense. The patient always describes it as ‘as if a knife was stuck in my eye’”.
Alberto Herrero, an affected person who last year had an electrode implanted in his brain as a last resort to control the disease, thus described its effects in statements to La Vanguardia: “It seems that they are burning your eye and they are trying to take it out. And your mouth, head, neck, nose, hurts all at once. It is unbearable. And if someone wants to help you, you reject them, you speak badly to them without meaning to. “No wonder they call it a suicide headache or suicide headache, because it’s unbearable and you want to be done with it all.”
The 16 research groups (including the one in Vall d’Hebron) integrated into the International Consortium, in parallel with the pharmaceutical industry, will continue to work in search of new therapeutic targets, with the difficulty of developing clinical trials due to the scarcity of those affected. The United States has approved a monoclonal antibody that has been shown to be effective in a study, but in Europe it can only be administered as compassionate use, since parallel trials are required for its approval.
