Smoking and cluster headache presentation and responsiveness to treatment

Though an association between cluster headache (CH) and smoking has been postulated, data from the Middle East region is scarce. To study the relationship between smoking and CH clinical characteristics and responsiveness to therapy in Egypt. This was a prospective cohort hospital-based study conducted on patients with episodic and chronic CH in a tertiary headache clinic in Egypt during the period between 2019 and 2023. Patients were consecutively recruited at the time of their presentation and were followed up for two weeks after initiation of prophylactic treatment and steroids (as transitional therapy). Of 172 patients with CH recruited, 144 (83.7%) were smokers. Twenty-eight patients (16.3%) had chronic CH. The mean age was 42.08 ± 10.93 (20–66) years, and 131 (76.2%) were males. Smokers had a significantly higher median number of cluster bouts in the past five years (3.0 (IQR2.0–4.0) versus 2.0 (IQR 1.0–2.0)) and worse HIT-6 scores [51.0 (44.0–59.75) versus 41.0 (38.0–41.75)] than non-smokers (p < 0.001). The number of cluster bouts in the past five years was positively correlated with the smoking index (r = 0.249 (p = 0.006) and the smoking duration (in years) (r = 0.392 (p < 0.001)). HIT-6 scores were significantly correlated with the age at smoking onset (r=-0.190, = 0.023), smoking index (r = 0.519, p < 0.001), smoking duration (r = 0.611, p < 0.001), and number of cigarettes consumed per day (r = 0.392, p < 0.001). Smoking is significantly correlated with the daily frequency of CH attacks, the frequency of CH bouts in the past five years, and the HIT-6 scores among our cohort.