Introduction: Obstructive sleep apnea (OSA) is a biological plausible risk factor for leukoaraiosis (LA). We tested the hypothesis that polysomnographic (PSG) and sleep-related variables are associated to LA in OSA patients.
Methods: Cross-sectional study in which PSG records, medical histories and brain 1.5T MRI were collected from all consecutive patients who had attended a Sleep Medicine Center between 2009-2014. LA was graded from 0 to 9 with the ’Atherosclerosis Risk In Communities’ study scale. OSA was defined by The International Classification of Sleep Disorders, 2014, and its severity categorizing according to apnea-hypopnea index (AHI, <15 mild, 15 to <30 moderate, 30 to <45 severe and ≥45 very severe). A multinomial logistic regression was performed to describe the association between OSA severity and LA (divided into 2 groups: mild-to-moderate LA and non-to-minimal LA). The covariates for all regression models were age, gender, BMI, hypertension, ischemic stroke, myocardial infarction, diabetes and pack-year of smoking.
Results: From 82 OSA patients (77% male; mean age 58±9 years, range 19-91), 54 (66%) had LA. Mild-to-moderate LA was found in 13 patients (8 mild and 5 moderate LA) and non-to-minimal LA in 69 (41 minimal and 28 non LA). Spearman’s correlation coefficient between AHI and LA grade was 0.41 (p<0.001). Furthermore, the higher OSA severity, the higher LA severity (p<0.001, for Jonckheere-Terpstra test for ordered alternatives). In the multinomial logistic regression model adjusted for cofounders, severe OSA patients had higher risk for mild or moderate LA (HR 12.8, 95% IC 1.2-141) compared to mild-to-moderate OSA patients. Additionally, self-reported habitual sleep duration from 7 to 9 hours (HR 0.36, 90% IC 0.14-0.90) and proportion of time in apnea/hypopnea over total sleep time (HR 1.04 for one unit increase, 90% IC 1.01-1.08) could be associated with the presence of LA (adjusted only for age and gender). In a multiple regression analysis with all the aforementioned variables, age (p=0.002), diabetes (p=0.003), and OSA severity (p=0.04) were predictors of the presence of LA.
Conclusion: Patients with severe OSA had higher risk for mild to moderate LA when compared to patients with mild or moderate OSA.