Background: The objective was to investigate the prevalence and clinical characteristics of sleep apnoea headache.
Methods: A postal questionnaire was received by 40,000 Norwegians from the general population. A total of 376 and 157 persons with high and low risk of sleep apnoea according to the Berlin Questionnaire had a polysomnography, and a clinical interview and examination by physicians.
Results: Sleep apnoea headache was diagnosed in 11.8% of the participants with obstructive sleep apnoea (OSA), while morning headache with similar symptomatology was diagnosed in 4.6% of the participants without OSA (p = 0.002). After adjusting for potential confounders the odds ratio for OSA remained significantly increased among participants with morning headache with an adjusted odds ratio of 2.92 (1.31-6.51). When using a cut-off of moderate (apnoea hypopnea index, AHI ≥ 15) and severe (AHI ≥ 30) OSA, the prevalence of sleep apnoea headache was 11.6% and 13.3%, respectively. Average oxygen desaturation and lowest oxygen saturation was not significantly different in participants with OSA with and without morning headache.
Conclusion: Morning headaches were significantly more frequent among participants with OSA than those without OSA. Sleep apnoea headache is less common in the general population than has previously been reported in clinic populations. The relation of hypoxia and morning headache is questioned.