OSAS-related headache and other primary headaches in obstructive sleep apnea syndrome: Clinical features, risk factors, frequency, and association with oxidative and inflammatory biomarkers

Obstructive sleep apnea syndrome is a condition that causes not only excessive daytime sleepiness, decreased concentration, but also headaches. Although the sleep disturbance because of sleep fragmentation, hypoxia, hypercapnia are considered to be the underlying mechanism of sleep apnea headache classified as a secondary headache according to the ICHD and primary headaches concomitant with OSAS, its pathophysiology has not been clearly elucidated. The aim of this study is to find out the frequency and clinical characteristics of primary headaches and sleep apnea headache and to investigate the relationship between PSG findings, and oxidative and inflammatory markers that develop secondarily oxidative processes. Between June 2024 and June 2025, 154 patients over the age of 18 who were diagnosed with OSAS using polysomnography (PSG) and evaluated at the neurology outpatient clinic of Karadeniz Teknik University, Faculty of Medicine were included in the study. The patients who have sleep disorders other than OSAS, and secondary headaches not related to sleep apnea headaches have been excluded. The characteristics of headache, PSG findings, CBC, serum oxidative and inflammatory markers, Epworth sleepiness scale, Beck's depression inventory, and Beck's anxiety inventory have been evaluated. Of the 154 patients, 67.5% (n=104) were male, 32.5% (n=50) were female, and the mean age was 50.3 years (±12.8 SD). Headache was reported in 43.5% of all patients (n=67), morning headache in 34.4% (n=53), and sleep apnea headache in 24%. Of the 67 patients with headaches, 37 (55.2%) had sleep apnea-related headaches, 22 (32.8%) had tension-type headaches, and 10 (14.9%) met the diagnostic criteria for migraine. The rate of female patients was higher in all headache groups (p<0,05). Epworth sleepiness scale (p=0,002), median Beck's depression and anxiety scores (p<0,001), and LDL (p=0.004) were significantly higher in headache and morning headache groups. BMI (p=0,004), Epworth sleepiness scale (p=0,022), the period during oxygen saturation remains below 90% were significantly higher, and minimum oxygen saturation was significantly lower in patients whose headache were morning headache. In this group there is no difference was found in terms of median Beck's depression and anxiety scores, and LDL. There is no significant difference was found with regard to AHI in any groups. To sum up; the morning headache frequency is 34% in patients with OSAS, and the headaches are bilateral, nonpulsatile, have mostly mild or moderate intensity in accordance with literature. The higher Epworth sleepiness score, lower minimum oxygen saturation, and longer duration of oxygen desaturation detected in patients with morning headaches suggest that OSAS-related morning headaches are primarily affected by the depth and duration of hypoxemia. Keyword: sleep apnea, headache, morning headache, hypoxia.