Associations between sleep disturbance and primary headaches: the third Nord-Trøndelag Health Study

The aim of the study was to evaluate the association between sleep disturbance and headache type and frequency, in a random sample of participants in the third Nord-Trøndelag Health Survey. The headache diagnoses were set by neurologists using the ICHD-2 criteria performing a semi structured face-to-face interview. Sleep problems were measured by the two validated instruments Karolinska Sleep Questionnaire (KSQ) and Epworth Sleepiness Scale (ESS). Among 297 participants, 77 subjects were headache-free, whereas 135 were diagnosed with tension-type headache (TTH), 51 with migraine, and 34 with other headache diagnoses. In the multivariate analyses, using logistic regression, excessive daytime sleepiness, defined as ESS >or= 10, was three times more likely among migraineurs compared with headache-free individuals (OR = 3.3, 95% CI 1.0-10.2). Severe sleep disturbances, defined as KSQ score in the upper quartile, was five times more likely among migraineurs (OR = 5.4, 95% CI 2.0-15.5), and three times more likely for subjects with TTH (OR = 3.3, 1.4-7.3) compared with headache-free individuals. Subjects with chronic headache were 17 times more likely to have severe sleep disturbances (OR = 17.4, 95% CI 5.1-59.8), and the association was somewhat stronger for chronic migraine (OR = 38.9, 95% CI 3.1-485.3) than for chronic TTH (OR = 18.3, 95% CI 3.6-93.0). In conclusion, there was a significant association between severe sleep disturbances and primary headache disorders, most pronounced for those with chronic headache. Even though one cannot address causality in the present study design, the results indicate an increased awareness of sleep problems among patients with headache.