Relationship between insomnia and headache in community-based middle-aged Hong Kong Chinese women

Limited studies have investigated the prevalence of insomnia symptoms among individuals with different headache diagnoses and the association between insomnia and headache in subjects with comorbid anxiety and depression. A total of 310 community-dwelling Hong Kong Chinese women aged 40-60 years completed a self-administered questionnaire on headache, sleep difficulties, mood disturbances, and functional impairment. About 31% of the sample complained of recurrent headache unrelated to influenza and the common cold in the past 12 months. The percentages of women diagnosed to have migraine, tension-type headache (TTH), and headache unspecified were 8.4, 15.5 and 7.1%, respectively. The most frequent insomnia complaint was "problem waking up too early" (29.4%), followed by "difficulty staying asleep" (28.0%) and "difficulty falling asleep" (24.4%). Women with headaches were significantly more likely to report insomnia symptoms than those without headaches. There were no significant differences among women with migraine, TTH, and headache unspecified in the prevalence of insomnia symptoms. Logistic regression analysis showed that women with insomnia disorder as defined by an insomnia severity index total score >or=8 had 2.2-fold increased risk of reporting recurrent headache, 3.2-fold increased risk of migraine, and 2.3-fold increased risk of TTH, after adjusting for anxiety and depression. Individual insomnia symptoms were not independent predictors. The association between insomnia and headache was stronger in subjects with more frequent headaches. Our findings suggest that insomnia and the associated distress, but not insomnia symptoms alone, is an independent risk factor for recurrent headache in middle-aged women with mixed anxiety, depression and sleep disturbances.