Cohort profile: the Western Australian Sleep Health Study.

BACKGROUND: Epidemiologic and genetic studies of obstructive sleep apnoea (OSA) are limited by a lack of large-scale, well-characterized OSA cohorts. These studies require large sample size to provide adequate power to detect differences between groups. This study describes the development of such a cohort (The Western Australian Sleep Health Study) in OSA patients of Caucasian-European origin attending the only public sleep clinic in Western Australia (WA). AIMS: The main aim of the study is to phenotype 4,000 OSA patients in order to define the genetics of OSA and its co-morbidities. METHODS: Almost all underwent laboratory-based attended polysomnography (PSG). RESULTS: Currently complete data (questionnaire, biochemistry, DNA, and PSG) has been obtained on over 3,000 individuals and will reach the target of 4,000 individuals by the end of 2010. In a separate but related study, we have developed a sleep study database containing data from all patients who have undergone PSG at the sleep laboratory since its inception in 1988 until the present day (over 30,000 PSG studies representing data from approximately 20,000 individuals). In addition, data from both cohorts have been linked prospectively to statutory health data collected by the WA Department of Health. CONCLUSION: This study will be the largest sleep clinic cohort database internationally with access to genetic and epidemiological data. It is unique among sleep clinic cohorts because of its size, the breadth of data collected and the ability to link prospectively to statutory health data. It will be a major tool to comprehensively assess genetic and epidemiologic factors determining OSA and its co-morbidities.

Obstructive sleep apnea and depression: A systematic review and meta-analysis.

INTRODUCTION: The present study aimed to review the association between obstructive sleep apnea (OSA) and depression and compare the prevalence of depression among people with and without OSA. METHODS: Systematic review and meta-analysis following PRISMA guidelines. We searched for papers published between 1 January 2010 and 20 October 2019 listed on the following databases: Embase, Ovid MEDLINER(R) and PsychINFO. The search terms included a combination of keywords related to sleep apnea and depression. We also completed a manual search of the references listed in the articles retrieved and grouped them according to study design: cross-sectional, case-control and longitudinal. Scale scores were standardised for comparison. RESULTS: Our search strategy yielded 1158 papers, of which 34 were considered suitable of review and 11 reported data that could be used for meta-analysis. Data from the 6 cross-sectional studies found no compelling evidence of an association between OSA and depression (odds ratio = 1.12, 95 % confidence interval, 95 %CI = 0.78, 1.47), but the meta-analysis of 5 longitudinal studies indicated that people with OSA were at greater risk of developing depression during follow-up than those without OSA (non-specific risk ratio (RR) = 2.18, 95 %CI = 1.47, 2.88), although there was evidence of high study heterogeneity (I2 = 72.8 %). DISCUSSION: The results of this systematic review and meta-analysis of observational studies is consistent with the hypothesis that OSA may increase the risk of depression. Sample characteristics and various methodological issues create uncertainty about the validity and generalizability of these associations.

Depressive Symptoms before and after Treatment of Obstructive Sleep Apnea in Men and Women.

STUDY OBJECTIVES: To determine prevalence of depressive symptoms in obstructive sleep apnea (OSA) and the impact of OSA treatment on depression scores. METHODS: Consecutive new patients referred for investigation of suspected OSA were approached. Consenting patients completed a patient health questionnaire (PHQ-9) for depressive symptoms when attending for laboratory polysomnography. Those with moderate/severe (apneahypopnea index [AHI] ≥ 15 events/h) and/or symptomatic mild OSA (AHI 5-14.99 events/h) were offered continuous positive airway pressure (CPAP) therapy. PHQ-9 was repeated after 3 months of CPAP with compliance recorded. Of a maximum PHQ-9 score of 27, a cut point ≥ 10 (PHQ-9 ≥ 10) was used to indicate presence of clinically significant depressive symptoms. RESULTS: A total of 426 participants (243 males) were recruited. Mean ± standard deviation body mass index (BMI) was 32.1 ± 7.1 kg/m2 and AHI 33.6 ± 28.9 events/h. PHQ-9 was 10.5 ± 6.1 and independently related to AHI (p < 0.001) and BMI (p < 0.001). In those without OSA, PHQ-9 ≥ 10 was more common in women, but no gender difference was evident with OSA. Of 293 patients offered CPAP, 228 were compliant (mean nightly use > 5 h) over 3 months of therapy. In them, with therapy, AHI decreased from 46.7 ± 27.4 to 6.5 ± 1.6 events/h, PHQ-9 from 11.3 ± 6.1 to 3.7 ± 2.9 and PHQ-9 ≥ 10 from 74.6% to 3.9% (p < 0.001 in each case). Magnitude of change in PHQ-9 was similar in men and women. Antidepressant use was constant throughout. CONCLUSIONS: Depressive symptoms are common in OSA and related to its severity. They improve markedly with CPAP, implying a relationship to untreated OSA.