The impact of obstructive sleep apnea on the circadian rest-activity rhythm: a cross-sectional analysis of the ELSA-Brasil cohort

<bold>Background:</bold> Despite the evidence regarding the effects of obstructive sleep apnea (OSA) on the circadian pattern of blood pressure, there is a lack of information concerning the influence of this pathology on the circadian rhythms of other physiological events. <bold>Objective:</bold> To investigate whether OSA affects the circadian rest-activity rhythm. <bold>Methods:</bold> Cross-sectional analysis of the ELSA-Brasil cohort. Adult civil servants were consecutively recruited, OSA was diagnosed through home sleep monitoring (apnea-hypopnea index [AHI] ≥15 events/h), and the rest-activity rhythm was assessed through actigraphy. The circadian function was defined by the variability/fragmentation (IV), stability (IS), and amplitude (RA) of the rhythm. <bold>Results:</bold> The cohort included 1,828 subjects (56.1% females) with a median [p25;p75] age of 48.0 [44.0;54.0] years. With a prevalence estimated at 32.6%, OSA was associated with an increased IV (0.84 [0.69;0.97] vs. 0.78 [0.66;0.91]) and a decreased RA (0.88 [0.82;0.92] vs. 0.92 [0.87;0.95]), which was no longer observed after adjusting for confounding factors. Additional analysis revealed a pattern of characteristics related to a disruption of the rhythm represented by a decreased total sleep time, excessive somnolence, and an increased percentage of time with an oxygen saturation <90%. Such pattern presented a dose-response relationship with the IV, RA, and IS (p<0.001). <bold>Conclusion:</bold> The findings reveal a specific pattern of characteristics associated with a rest-activity rhythm disruption among OSA patients. This highlights the relevance of variables other than the AHI and the need for a precision medicine-centered approach within this context.