Insomnia and Periodicity of Headache in an Arctic Cluster Headache Population

• Published in: Headache: The Journal of Head and Face Pain
• Main Authors: Ofte, Hilde K., Berg, Diana H., Bekkelund, Svein I., Alstadhaug, Karl B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2013
• Subjects: Arctic
• Online Access: http://dx.doi.org/10.1111/head.12241; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fhead.12241; http://onlinelibrary.wiley.com/wol1/doi/10.1111/head.12241/fullpdf

Objective To assess the prevalence of chronic insomnia and the periodicity of headache attacks in an A rctic cluster headache population. Background Cluster headache is a sleep‐related disorder, and attacks have both circadian and circannual rhythmicity. Methods Through a retrospective hospital chart review, we identified all subjects diagnosed with episodic cluster headache ( ICD ‐10 G 44.0) at the N eurological D epartments in N orthern N orway (located north of 66°33′ N ) between J anuary 1, 2000 and D ecember 31, 2010. Patients with a confirmed diagnosis ( ICHD ‐2) received a comprehensive questionnaire covering demographic data, clinical characteristics, sleep, and periodicity of attacks. Results A total of 196 subjects were registered, and 178 received the questionnaire. The response rate was 88/178 (49%). Fifty‐eight men (aged 49.2 ± 13.6) and 12 women (aged 49.7 ± 15.5) were included. Forty percent of the responders suffered from chronic insomnia ( D iagnostic and S tatistical M anual of M ental D isorders 4th edition). Forty‐nine percent of the responders and 42% of the non‐responders were shift workers, which is much higher than compared with the general population (24%). Insomnia was significantly associated with shift work and experiencing longer‐lasting cluster bouts. One third attributed their insomnia to the cluster headache. Thirty‐seven percent reported a seasonal predilection of the cluster periods, and 58% a diurnal periodicity of attacks. Eighty percent often or always had headache attacks during sleep, the most frequent time interval being at 12:00‐4:00 am . Shift workers were significantly more likely to see lack of sleep as a cluster attack trigger than daytime workers. Conclusions Chronic insomnia and shift work seem to be common among A rctic cluster headache patients. The small number of subjects included in this study implies that conclusions should be drawn with caution, but the findings support the idea of cluster headache as a circadian rhythm disorder.