ObjectivesIn the literature, several studies have investigated the particular relationship between major depression and obstructive sleep apnoea syndrome (OSAS). However, most of these studies have focused primarily on middle-aged to elderly individuals (≥40 years) which means that this problem has been little studied in young adults (<30 years). Nevertheless, in young adults the prevalence of major depression (particularly its atypical subtype) is not negligible, which seems to justify carrying out additional investigations in order to allow a better understanding of the potential role played by major depression in the pathophysiology of OSAS in this particular subpopulation. The aim of this study was therefore to empirically investigate the prevalence of OSAS in young adults and to study the risk of OSAS associated with major depression in this particular subpopulation. MethodsPolysomnographic and demographic data from 264 young adults were collected from the Erasme Hospital Sleep Laboratory (Brussels, Belgium) database to enable our analyses. During their two-night stay (including a first night of habituation and a night of polysomnography) at the Sleep Laboratory, these individuals underwent a complete somatic assessment (including blood test, electrocardiogram, daytime electroencephalogram and urinalysis), a systematic psychiatric assessment by a unit psychiatrist and an assessment of their complaints related to sleep. These different steps made it possible to systematically diagnose all somatic pathologies, psychiatric disorders according to the diagnostic criteria of the DSM-IV-TR and sleep pathologies according to the diagnostic criteria of the AASM. This allowed the selection of young adults included in our study based on our inclusion and exclusion criteria. Polysomnographic recordings from our Sleep Laboratory were visually scored according to AASM criteria. An obstructive sleep apnoea-hypopnoea index ≥5/hour was used for the diagnosis of OSAS. At the statistical level, in order to allow our analyses, we subdivided our sample of young adults into two groups: a control group without OSAS (n=215) and a patient group with OSAS (n=49). After checking the normal distribution of our data, normally distributed data were analysed with t-tests whereas asymmetrically or dichotomously distributed data were analysed with Wilcoxon tests or Chi2 tests. Univariate regression models were used to study the risk of OSAS associated with major depression (categorized: absent, typical, atypical) in young adults and potential confounding factors. In multivariate regression models, the risk of OSAS associated with major depression (categorized: absent, typical, atypical) in young adults was adjusted only for confounding factors significantly associated with OSAS during univariate analysis. These confounding factors were introduced in a hierarchical manner in the various multivariate regression models constructed. ResultsThe prevalence of OSAS in our population of young adults was 18.6 %. During univariate analyses, atypical depression [OR 2.51 (95% CI 1.18–5.32), p-value=0.014], male gender [OR 4.53 (95% CI 2.20–9.34), P-value <0.001], presence of snoring [OR 2.51 (95% CI 1.33–4.75), P-value=0.005], presence of at least one cardio-metabolic alteration [OR 2.26 (95% CI 1.19–4.28), P-value=0.012], body mass index>30 kg/m2 [OR 4.55 (95% CI 2.07–10.03), P-value <0.001] and ferritin ≥150 μg/L [OR 3.28 (95% CI 1.69–6.36), P-value<0.001] were associated with increased risk of OSAS in our population of young adults. After adjusting for these major confounding factors associated with OSAS (gender, body mass index, cardio-metabolic alterations, ferritin level, and snoring) in the four models studied, multivariate regression analyses confirmed that unlike typical depression, atypical depression [OR 3.09 (95% CI 1.26–7.54), P-value=0.019] was a risk factor for OSAS in young adults. ConclusionsIn our study, we demonstrated that the prevalence of OSAS was 18.6 % in young adults referred to the Erasme Hospital Sleep Laboratory. In addition, we have shown that unlike typical depression, atypical depression was associated with an increased risk of OSAS in young adults, which seems to justify more systematic research of this pathology in young adults suffering from atypical depression in order to allow the establishment of adapted therapeutic strategies and avoid the negative consequences associated with the co-occurrence of these two pathologies.