This just in: the first study to systematically evaluate cluster headache in individuals never exposed to tobacco smoke versus those who have been exposed.
People with cluster headache who have never been exposed to tobacco may have a different type of headache syndrome than those with cluster headache who have been exposed to tobacco, either through a personal history of smoking or through secondhand smoke.1A recent study found that those exposed to tobacco smoke may have a worse headache syndrome, and more headache-related disability than those who were never exposed to tobacco.
“The nonexposed subtype appears to have an earlier age of onset, higher rate of familial migraine, and less circadian periodicity and daytime entrainment, suggesting a possible different underlying pathology than in the tobacco-exposed subform,” wrote Todd Rozen, MD, FAAN, of Mayo Clinic Florida, Jacksonville, Florida.
The study is first to systematically evaluate cluster headache in individuals never exposed to tobacco smoke. Past studies have focused on individuals exposed to tobacco and found a very strong link between smoking and increased risk for cluster headache. However, the cause has yet to be established. Some nonsmokers also develop cluster headache, further complicating the issue.
To provide more evidence, researchers used data from the US Cluster Headache Survey, the largest survey completed to date about cluster headache in the US.2 The study took place from October through December 2008 and consisted of a web-based questionnaire with 187 multiple choice questions. Only patients with neurologist-diagnosed cluster headache were eligible to complete the survey.
The analysis included responses from 1134 individuals. Twelve percent of respondents had no personal history of smoking or exposure to second-hand smoke in their childhood home (never-exposed group). Eighty-eight percent had either a personal history of smoking or had been exposed to smoke in their childhood home (exposed group).
Results suggested that a significantly higher percentage of the never exposed group was diagnosed at a younger age, had a stronger family history of migraine, and had more variable headache cycles than the exposed group.
In contrast, a significantly higher percentage of the exposed group had a history of head trauma, experienced worsening of their headaches from episodic to chronic, had more frequent attacks, and had more severe symptoms, such as runny nose, agitation and suicidal ideation.
The exposed group also had a significantly higher percentage of heavy coffee drinkers and headaches triggered by alcohol. Additionally, they had more work disability and lost days from work than the never exposed group, but these results were not significant.
Both exposed and nonexposed groups had poor overall response to preventive and abortive medication, except for inhaled oxygen and injectable sumatriptan (see Table).
The authors mentioned that the younger age of onset and stronger family history of migraine in the never exposed group could suggest a genetic contribution to this type of cluster headache. The later age of onset in the exposed group could result from the toxicity of cigarette smoke. Many individuals in this group continued smoking after their diagnosis of cluster headache, and continued smoking could be a risk factor for worsening of cluster headache from an episodic to a chronic condition.
However, further study is needed to confirm the results and evaluate underlying mechanisms. The study did not confirm cluster headache diagnosis. Some participants may have instead suffered from migraine, which could have biased results. Also, the study could not evaluate other types of secondhand smoke exposure beyond what occurred in the childhood home.
Take home points
• First study to systematically evaluate cluster headache in individuals never exposed to tobacco suggests two subtypes for cluster headaches: tobacco-exposed and tobacco never-exposed
• Tobacco never-exposed had earlier age of onset and stronger family history of migraine, suggesting a genetic contribution
• Tobacco-exposed had later age of onset, more severe symptoms and more disability, suggesting toxic effects of cigarette smoke
• Further research is needed to confirm results and evaluate underlying mechanisms
1. Rozen TD. Cluster Headache Clinical Phenotypes: Tobacco Nonexposed (Never Smoker and No Parental Secondary Smoke Exposure as a Child) versus Tobacco-Exposed: Results from the United States Cluster Headache Survey. Headache. 2018;58:688-699.
2. Rozen TD, Fishman RS. Cluster headache in the United States of America: demographics, clinical characteristics, triggers, suicidality, and personal burden. Headache. 2012;52:99-113.