The Relation Between Apnea and Depressive Symptoms in Men with Severe Obstructive Sleep Apnea: Mediational Effects of Sleep Quality

We determined the relationship between apnea severity and depressive symptoms in a large sample of the newly diagnosed male patients with severe obstructive sleep apnea (OSA). Data were collected from patients who received polysomnography due to suspected OSA. The questionnaires included the Beck Depression Inventory (BDI), Epworth Sleepiness Scale (ESS), and Medical Outcomes Study (MOS)-Sleep Scale, for which Sleep Problems Index-1 (SPI-1) was calculated. The apnea-hypopnea index (AHI) and respiratory distress index (RDI) were used to measure apnea severity. The mediational model, which states that OSA severity affects depression through a mediator, was tested here. In total, 302 male patients with severe OSA participated. The mean patient age was 48.4 years (SD = 11.3 years). The BDI was a parts per thousand yen10 in 118 patients (39 %) and was significantly associated with body mass index (r = 0.114; p = 0.048), ESS (r = 0.164; p = 0.004), SPI-1 (r = 0.453; p < 0.001), and RDI (r = 0.126; p = 0.029). According to the linear regression analyses, the RDI is not independently associated with the BDI. The strongest predictor of BDI was sleep quality (SPI-1; beta = 0.425; p < 0.001). The bootstrap method confirmed that the depressive effects of RDI are significantly mediated by poor sleep quality (bootstrapped 95 % CI 0.0113-0.0632). There is evidence of a mediational role of subjective sleep quality on the relationship between apnea severity and depressive symptoms in male patients with severe OSA.