Associations of early life and childhood risk factors with obstructive sleep apnoea in middle-age.

BACKGROUND AND OBJECTIVE: Early-life risk factors for obstructive sleep apnoea (OSA) are poorly described, yet this knowledge may be critical to inform preventive strategies. We conducted the first study to investigate the association between early-life risk factors and OSA in middle-aged adults. METHODS: Data were from population-based Tasmanian Longitudinal Health Study cohort (n = 3550) followed from 1st to 6th decades of life. Potentially relevant childhood exposures were available from a parent-completed survey at age 7-years, along with previously characterized risk factor profiles. Information on the primary outcome, probable OSA (based on a STOP-Bang questionnaire cut-off ≥5), were collected when participants were 53 years old. Associations were examined using logistic regression adjusting for potential confounders. Analyses were repeated using the Berlin questionnaire. RESULTS: Maternal asthma (OR = 1.5; 95% CI 1.1-2.0), maternal smoking (OR = 1.2; 1.05, 1.5), childhood pleurisy/pneumonia (OR = 1.3; 1.04, 1.7) and frequent bronchitis (OR = 1.2; 1.01, 1.5) were associated with probable OSA. The risk-factor profiles of 'parental smoking' and 'frequent asthma and bronchitis' were also associated with probable OSA (OR = 1.3; 1.01, 1.6 and OR = 1.3; 1.01-1.9, respectively). Similar associations were found for Berlin questionnaire-defined OSA. CONCLUSIONS: We found novel temporal associations of maternal asthma, parental smoking and frequent lower respiratory tract infections before the age of 7 years with adult OSA. While determination of their pathophysiological and any causal pathways require further research, these may be useful to flag the risk of OSA within clinical practice and create awareness and vigilance among at-risk groups.

Association of novel adult cough subclasses with clinical characteristics and lung function across six decades of life in a prospective, community-based cohort in Australia: an analysis of the Tasmanian Longitudinal Health Study (TAHS).

BACKGROUND: Cough is a common yet heterogeneous condition. Little is known about the characteristics and course of cough in general populations. We aimed to investigate cough subclasses, their characteristics from childhood across six decades of life, and potential treatable traits in a community-based cohort. METHODS: For our analysis of the Tasmanian Longitudinal Health Study (TAHS), a prospective, community-based cohort study that began on Feb 23, 1968, and has so far followed up participants in Tasmania, Australia, at intervals of 10 years from a mean age of 7 years to a mean age of 53 years, we used data collected as part of the TAHS to distinguish cough subclasses among current coughers at age 53 years. For this analysis, participants who answered Yes to at least one cough-related question via self-report questionnaire were defined as current coughers and included in a latent class analysis of cough symptoms; participants who answered No to all nine cough-related questions were defined as non-coughers and excluded from this analysis. Two groups of longitudinal features were assessed from age 7 years to age 53 years: previously established longitudinal trajectories of FEV1, forced vital capacity [FVC], FEV1/FVC ratio, asthma, and allergies-identified via group-based trajectory analysis or latent class analysis-and symptoms at different timepoints, including asthma, current productive cough, ever chronic productive cough, current smoking, and second-hand smoking. FINDINGS: Of 8583 participants included at baseline in the TAHS, 6128 (71·4%) were traced and invited to participate in a follow-up between Sept 3, 2012, and Nov 8, 2016; 3609 (58·9%) of these 6128 returned the cough questionnaire. The mean age of participants in this analysis was 53 years (SD 1·0). 2213 (61·3%) of 3609 participants were defined as current coughers and 1396 (38·7%) were categorised as non-coughers and excluded from the latent class analysis. 1148 (51·9%) of 2213 participants in this analysis were female and 1065 (48·1%) were male. Six distinct cough subclasses were identified: 206 (9·3%) of 2213 participants had minimal cough, 1189 (53·7%) had cough with colds only, 305 (13·8%) had cough with allergies, 213 (9·6%) had intermittent productive cough, 147 (6·6%) had chronic dry cough, and 153 (6·9%) had chronic productive cough. Compared with people with minimal cough, and in contrast to other cough subclasses, people in the chronic productive cough and intermittent productive cough subclasses had worse lung function trajectories (FEV1 persistent low trajectory 2·9%, 6·4%, and 16·1%; p=0·0011, p<0·0001; FEV1/FVC early low-rapid decline trajectory 2·9%, 12·1%, and 13·0%; p=0·012, p=0·0007) and a higher prevalence of cough (age 53 years 0·0%, 32·4% [26·1-38·7], and 50·3% [42·5-58·2]) and asthma (age 53 years 6·3% [3·7-10·6], 26·9% [21·3-33·3], and 41·7% [24·1-49·7]) from age 7 years to age 53 years. INTERPRETATION: We identified potential treatable traits for six cough subclasses (eg, asthma, allergies, and active and passive smoking for productive cough). The required management of productive cough in primary care (eg, routine spirometry) might differ from that of dry cough if our findings are supported by other studies. Future population-based studies could apply our framework to address the heterogeneity and complexity of cough in the community. FUNDING: The National Health and Medical Research Council of Australia, The University of Melbourne, Clifford Craig Medical Research Trust of Tasmania, Victorian Asthma Foundation, Queensland Asthma Foundation, Tasmanian Asthma Foundation, The Royal Hobart Hospital Research Foundation, the Helen MacPherson Smith Trust, GlaxoSmithKline, and the China Scholarship Council.

Longitudinal risk factors for obstructive sleep apnea: A systematic review.

Despite substantial disease burden, existing evidence on the risk factors for obstructive sleep apnea (OSA) have been derived primarily from cross-sectional studies without determining temporality. Therefore, we aimed to systematically synthesize the literature on longitudinal risk factors for sleep study-assessed OSA and questionnaire-assessed probable OSA from cohort studies in the general adult population settings. We systematically searched Embase and Medline (on OVID) databases. Eleven studies met the inclusion criteria. Meta-analyses were not conducted due to methodological heterogeneity of exposure and outcome measurements. There was consistent evidence that weight gain was associated with incident (n = 2) and greater severity (n = 2) of OSA. One study each observed an association of higher baseline body-mass index, male sex, asthma, a specific genetic polymorphism in rs12415421, and insulin resistance/hyperglycemia, with incident OSA. Long-term exposure to ambient air pollution (NO2, n = 1) was associated with OSA, and menopausal transitions (n = 1) with higher apnea-hypopnea index. There were no eligible studies on long-term smoking or alcohol use. In conclusion, approximately 10% increase in weight, especially in males, might alert clinicians to consider potential or worsening OSA. Large, well-designed longitudinal studies are needed to consolidate knowledge on other associations with OSA development, especially on potentially modifiable risk factors.

Association of antenatal anxiety disorders with antenatal comorbidities and adverse pregnancy outcomes among clinic attendees at a tertiary-care hospital in Sri Lanka.

Purpose: Evidence on the association between antenatal anxiety disorders (AADs) and adverse pregnancy outcomes with detection of AADs using the gold-standard is scarce despite being vital to make decisions on interventions. We aimed to determine this association in women attending tertiary-care antenatal clinics in Sri Lanka. Material and methods: Presence/absence of AADs in a systematic random sample of 221 antenatal women attending routine antenatal clinics of a teaching hospital who participated in a questionnaire-validation study were confirmed by a psychiatrist. These women were followed up until the end of pregnancy. Information on antenatal comorbidities, adverse pregnancy outcomes was extracted from health records. The association between AADs with antenatal comorbidities and adverse pregnancy outcomes were reported using adjusted odds ratios (ORs) and 95%confidence intervals (CIs) generated from logistic regression models. Results: Mean (±SD) age of the women was 30 (±5.8) years. AADs were diagnosed in 81 (37%) women. Compared to women without AADs, those who had AADs were more at risk of pregnancy-induced hypertension (OR 6.1; 95% CI 1.2-31.9), gestational diabetes mellitus (OR 12.6; 95% CI 1.5-107.2), preterm labour (OR 4.3; 95% CI 1.4-13.0), prolonged labour (OR 19.0; 95% CI 7.1-51.1), lower segment caesarean section (OR 4.7; 95% CI 2.5-8.7) and low birthweight (OR 11.2; 95% CI 4.8-26.3). All miscarriages, stillbirths and assisted labour occurred exclusively in those with AADs. Conclusions: AADs are strongly associated with several adverse pregnancy outcomes. Causal pathways and effect of interventions for AADs must be explored in future research.

Longitudinal Sleep Study in Pregnancy: Cohort Profile and Prevalence and Risk Factors for Sleep Symptoms in the First Trimester.

Sleep disorders could influence pregnancy outcomes but evidence for longitudinal associations is scarce. We established a prospective cohort of women to determine incident sleep issues and their adverse health outcomes during pregnancy and beyond, and present here the baseline cohort profile. Antenatal women in gestational weeks 8-12 were recruited (n = 535) and followed-up in each trimester and at 5-6 weeks postpartum (no attrition). Sleep symptoms and disorders were measured using STOP-Bang and Berlin questionnaires and Pittsburgh Sleep Quality Index. Incident health outcomes were extracted from clinical records. At the time of recruitment, habitual snoring was present in 13.8% of participants; "excessive sleepiness during the day" (EDS) in 42.8%; short (<7 h) sleep duration in 46.4%; "having trouble sleeping" in 15.3%; and "poor subjective sleep quality" in 8.6%. Habitual snoring was strongly associated with irregular menstrual periods for one year preceding pregnancy (p = 0.014) and higher BMI (p < 0.001). Higher age was associated with less "trouble sleeping" (OR 0.9, p = 0.033) and longer sleep duration was associated with better "subjective sleep quality" (OR 0.8, p = 0.005). Sleep issues were highly prevalent at baseline and associated with age, irregular menstruation, and obesity. This cohort will provide a robust platform to investigate incident sleep disorders during pregnancy and their effects on adverse pregnancy outcomes and long-term health of women and their offspring.

Association of helminth infestation with childhood asthma: a nested case-control study.

OBJECTIVES: The association between helminthiasis and asthma remains inconclusive but can only be investigated in counties where helminthiasis is transitioning from a high to low burden. We investigated this association using data from a childhood respiratory cohort in Sri Lanka. METHODS: A case-control study was nested within a population-based cohort of children aged 6-14 years in Sri Lanka. The stool samples of 190 children with asthma and 190 children without asthma were analyzed to assess the burden of helminth infestation. Logistic regression models were fitted to investigate the association of gastrointestinal helminth species with asthma. RESULTS: Helminthiasis in children with and without asthma was 23.3% (n = 44) and 15.3% (n = 23), respectively. Those with asthma were more likely to have helminthiasis (odds ratio 3.7; 95% confidence interval 1.7, 7.7; P = 0.001), particularly with Trichiuris trichura (odds ratio 4.5; 95% confidence interval 1.6, 12.3; P = 0.004). Helminth eggs per gram of feces were not associated with asthma (P >0.05). CONCLUSION: Our findings demonstrate a positive association between T. trichura infestation and asthma and point to the need to fully characterize this association to understand the likely immunological mechanism that drives it. This association highlights an important public health intervention in countries where these infestations are still prevalent, affecting 24% of the population worldwide.

Lifetime spirometry patterns of obstruction and restriction, and their risk factors and outcomes: a prospective cohort study.

BACKGROUND: Interest in lifetime lung function trajectories has increased in the context of emerging evidence that chronic obstructive pulmonary disease (COPD) can arise from multiple disadvantaged lung function pathways, including those that stem from poor lung function in childhood. To our knowledge, no previous study has investigated both obstructive and restrictive lifetime patterns concurrently, while accounting for potential overlaps between them. We aimed to investigate lifetime trajectories of the FEV1/forced vital capacity (FVC) ratio, FVC, and their combinations, relate these combined trajectory groups to static lung volume and gas transfer measurements, and investigate both risk factors for and consequences of these combined trajectory groups. METHODS: Using z scores from spirometry measured at ages 7, 13, 18, 45, 50, and 53 years in the Tasmanian Longitudinal Health Study (n=2422), we identified six FEV1/FVC ratio trajectories and five FVC trajectories via group-based trajectory modelling. Based on whether trajectories of the FEV1/FVC ratio and FVC were low (ie, low from childhood or adulthood) or normal, four patterns of lifetime spirometry obstruction or restriction were identified and compared against static lung volumes and gas transfer. Childhood and adulthood characteristics and morbidities of these patterns were investigated. FINDINGS: The prevalence of the four lifetime spirometry patterns was as follows: low FEV1/FVC ratio only, labelled as obstructive-only, 25·8%; low FVC only, labelled as restrictive-only, 10·5%; both low FEV1/FVC ratio and low FVC, labelled as mixed, 3·5%; and neither low FEV1/FVC ratio nor low FVC, labelled as reference, 60·2%. The prevalence of COPD at age 53 years was highest in the mixed pattern (31 [37%] of 84 individuals) followed by the obstructive-only pattern (135 [22%] of 626 individuals). Individuals with the mixed pattern also had the highest prevalence of parental asthma, childhood respiratory illnesses, adult asthma, and depression. Individuals with the restrictive-only pattern had lower total lung capacity and residual volume, and had the highest prevalence of childhood underweight, adult obesity, diabetes, cardiovascular conditions, hypertension, and obstructive sleep apnoea. INTERPRETATION: To our knowledge, this is the first study to characterise lifetime phenotypes of obstruction and restriction simultaneously using objective data-driven techniques and unique life course spirometry measures of FEV1/FVC ratio and FVC from childhood to middle age. Mixed and obstructive-only patterns indicate those who might benefit from early COPD interventions. Those with the restrictive-only pattern had evidence of true lung restriction and were at increased risk of multimorbidity by middle age. FUNDING: National Health and Medical Research Council of Australia, The University of Melbourne, Clifford Craig Medical Research Trust of Tasmania, The Victorian, Queensland & Tasmanian Asthma Foundations, The Royal Hobart Hospital, Helen MacPherson Smith Trust, and GlaxoSmithKline.

The association between traffic-related air pollution and obstructive sleep apnea: A systematic review.

Recent evidence suggests that air pollution exposure may be a contributing risk factor for obstructive sleep apnea (OSA), however, current evidence is conflicting. This systematic review aims to determine the association between air pollution and OSA in the general population, and examine for potential effect modification by seasonality, temperature and humidity. Five full-text articles were included in the review out of 905 articles found by systematically searching PubMed, Embase and Scopus databases. The included studies were limited to OSA in adults that were conducted in middle to high-income countries. The results highlight heterogeneity in the diagnostic criteria for OSA and method used to assess air pollution exposure. There is some evidence to support a relationship between air pollution exposure and OSA. However, the duration of exposure to different air pollutants including particulate matter (PM2.5 and PM10) and nitric oxides (NO2) in relation to OSA varied across different seasons, temperatures, and countries. This variability of the pollutants across studies warrants a more robust study design using time-series analysis with multiple follow-ups to strengthen the evidence for this relationship before considering its implications.

Nocturnal symptoms perceived as asthma are associated with obstructive sleep apnoea risk, but not bronchial hyper-reactivity.

BACKGROUND AND OBJECTIVE: Obstructive sleep apnoea (OSA) and asthma are associated, and nocturnal breathing difficulty that is usually identified as asthma-like symptoms can be present in both conditions. We investigated how nocturnal asthma-like symptoms (NAS) and bronchial hyper-reactivity (BHR) contribute to the association between OSA risk and current asthma, which is currently unknown but a clinically important question. METHODS: We used data from 794 middle-aged participants in a population-based cohort who provided information on OSA risk (defined by a STOP-Bang questionnaire score of at least 3), current asthma and NAS, and underwent methacholine bronchial challenge testing. Using regression models, we examined the association between OSA risk and current asthma-NAS subgroups and investigated any effect modification by BHR. RESULTS: The participants were aged 50 years (49.8% male). OSA risk was associated with NAS with or without current asthma (odds ratio (OR): 2.6; 95% CI = 1.3-5.0; OR: 4.2; 95% CI = 1.1-16.1, respectively), but not with current asthma in the absence of NAS. BHR was associated with current asthma with or without NAS (OR: 2.9; 95% CI = 1.4-5.9; OR: 3.4; 95% CI = 2.0-7.0, respectively) but not with NAS in the absence of current asthma. The associations between OSA risk and current asthma were neither modified nor mediated by BHR. CONCLUSION: Our findings suggest that some of the nocturnal symptoms perceived as asthma may be OSA symptoms. Patients with nocturnal asthma symptoms should be considered for possible OSA.

Detecting sleep apnoea syndrome in primary care with screening questionnaires and the Epworth sleepiness scale.

OBJECTIVE: To examine the utility of apnoea screening questionnaires, alone and in combination with the Epworth sleepiness scale (ESS), for detecting obstructive sleep apnoea (OSA) in primary care. DESIGN, SETTING: Prospective validation study in an Australian general population cohort. PARTICIPANTS: 424 of 772 randomly invited Tasmanian Longitudinal Health Study, 6th decade follow-up participants with OSA symptoms (mean age, 52.9 years; SD, 0.9 year) who completed OSA screening questionnaires and underwent type 4 sleep studies. MAIN OUTCOME MEASURES: Clinically relevant OSA, defined as moderate to severe OSA (15 or more oxygen desaturation events/hour), or mild OSA (5-14 events/hour) and excessive daytime sleepiness (ESS ≥ 8); diagnostic test properties of the Berlin (BQ), STOP-Bang and OSA-50 questionnaires, alone or combined with an ESS ≥ 8. RESULTS: STOP-Bang and OSA-50 correctly identified most participants with clinically relevant OSA (sensitivity, 81% and 86% respectively), but with poor specificity (36% and 21% respectively); the specificity (59%) and sensitivity of the BQ (65%) were both low. When combined with the criterion ESS ≥ 8, the specificity of each questionnaire was high (94-96%), but sensitivity was low (36-51%). Sensitivity and specificity could be adjusted according to specific needs by varying the STOP-Bang cut-off score when combined with the ESS ≥ 8 criterion. CONCLUSIONS: For people likely to trigger OSA assessment in primary care, the STOP-Bang, BQ, and OSA-50 questionnaires, combined with the ESS, can be used to rule in, but not to rule out clinically relevant OSA. Combined use of the STOP-Bang with different cut-off scores and the ESS facilitates a flexible balance between sensitivity and specificity.

Comparison of apnoea-hypopnoea index and oxygen desaturation index when identifying obstructive sleep apnoea using type-4 sleep studies.

The concordance of different indices from type-4 sleep studies in diagnosing and categorising the severity of obstructive sleep apnoea is not known. This is a critical gap as type-4 sleep studies are used to diagnose obstructive sleep apnoea in some settings. Therefore, we aimed to determine the concordance between flow-based apnoea-hypopnoea index (AHIflow50% ) and oxygen desaturation index (ODI3% ) by measuring them concurrently. Using a random sub-sample of 296 from a population-based cohort who underwent two-channel type-4 sleep studies, we assessed the concordance between AHIflow50% and ODI3% . We compared the prevalence of obstructive sleep apnoea of various severities as identified by the two methods, and determined their concordance using coefficient Kappa(κ). Participants were aged (mean ±â€…SD) 53 ±â€…0.9 years (48% male). The body mass index was 28.8 ±â€…5.2 kg m-2 and neck circumference was 37.4 ±â€…3.9 cm. The median AHIflow50% was 5 (inter-quartile range 2, 10) and median ODI3% was 9 (inter-quartile range 4, 15). The obstructive sleep apnoea prevalence reported using AHIflow50% was significantly lower than that reported using ODI3% at all severity thresholds. Although 90% of those with moderate-severe obstructive sleep apnoea classified using AHIflow50% were identified by using ODI3% , only 46% of those with moderate-severe obstructive sleep apnoea classified using ODI3% were identified by AHIflow50% . The overall concordance between AHIflow50% and ODI3% in diagnosing and classifying the severity of obstructive sleep apnoea was only fair (κ = 0.32), better for males (κ = 0.42 [95% confidence interval 0.32-0.57] versus 0.22 [95% confidence interval 0.09-0.31]), and lowest for those with a body mass index ≥ 35 (κ = 0.11). In conclusion, ODI3% and AHIflow50% from type-4 sleep studies are at least moderately discordant. Until further evidence is available, the use of ODI3% as the measure of choice for type-4 sleep studies is recommended cautiously.

The effect of surgical weight loss on obstructive sleep apnoea: A systematic review and meta-analysis.

This review aimed to examine the relationship between surgical weight loss and obstructive sleep apnoea (OSA) severity (i.e., apnoea-hypopnoea index [AHI]), and how this relationship is altered by the various respiratory events scoring (RES) criteria used to derive the AHI. A systematic search of the literature was performed up to December 2017. Before-and-after studies were considered due to a paucity of randomised controlled trials (RCTs) available to be reviewed in isolation. Primary outcomes included pre- and post-surgery AHI and body mass index (BMI). Secondary outcomes included sleep study type and RES criteria. Meta-analysis was undertaken where possible. Overall, surgical weight loss resulted in reduction of BMI and AHI, however, OSA persisted at follow-up in the majority of subjects. There was high between-study heterogeneity which was largely attributable to baseline AHI and duration of follow-up when analysed using meta-regression. There was insufficient data to evaluate the impact of different RES criteria on OSA severity. Therefore, more RCTs are needed to verify these findings given the high degree of heterogeneity and future studies are strongly encouraged to report the RES criteria used to enable fair and uniform comparisons of the impact of any intervention on OSA severity.

Prediction models for the development of COPD: a systematic review.

Early identification of people at risk of developing COPD is crucial for implementing preventive strategies. We aimed to systematically review and assess the performance of all published models that predicted development of COPD. A search was conducted to identify studies that developed a prediction model for COPD development. The Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies was followed when extracting data and appraising the selected studies. Of the 4,481 records identified, 30 articles were selected for full-text review, and only four of these were eligible to be included in the review. The only consistent predictor across all four models was a measure of smoking. Sex and age were used in most models; however, other factors varied widely. Two of the models had good ability to discriminate between people who were correctly or incorrectly classified as at risk of developing COPD. Overall none of the models were particularly useful in accurately predicting future risk of COPD, nor were they good at ruling out future risk of COPD. Further studies are needed to develop new prediction models and robustly validate them in external cohorts.

Validity of the Berlin questionnaire in detecting obstructive sleep apnea: A systematic review and meta-analysis.

We aimed to systematically review the Berlin questionnaire as a screening tool for obstructive sleep apnea. We systematically searched PubMed, Embase, and Scopus databases, reviewed articles reporting the Berlin questionnaire's diagnostic utility as measured against type-1 polysomnography, and performed meta-analyses where possible. Thirty five eligible articles showed that the Berlin questionnaire's diagnostic utility varied by study population, definition of hypopnea used, and apnea-hypopnea index threshold used. It had good sensitivity and specificity for detecting clinically relevant obstructive sleep apnea as well as any obstructive sleep apnea in the sleep clinic population. Despite limited evidence, it showed modest to high sensitivity for detecting clinically relevant obstructive sleep apnea or any obstructive sleep apnea in other clinical and general population subgroups. Its specificity was relatively low. Possible reasons for variability in reported diagnostic utility of the Berlin questionnaire are multifaceted. We conclude that the Berlin questionnaire is useful as a clinical screening test and epidemiological tool in the sleep clinic population. Despite limited evidence, it likely has potential clinical and research utility in other populations. Adopting more consistent methodological definitions and focussing more on the general population and specific clinical populations to determine its usefulness as a clinical or epidemiological screening tool are recommended.

Current evidence on prevalence and clinical outcomes of co-morbid obstructive sleep apnea and chronic obstructive pulmonary disease: A systematic review.

The objective of this systematic review is to synthesize the evidence on prevalence, polysomnographic findings and clinical outcomes of co-morbid obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) - known as the "overlap syndrome". We systematically searched PubMed on 1 December 2015 using appropriate medical subject headings (MeSH) and text words to capture prevalence studies and comparative studies of any observational design examining the clinical outcomes in patients with co-existent COPD and OSA. We reviewed 591 articles and included 27 in the final review. In total, 21 observational studies (n = 29,341 participants) provided prevalence estimates. Overlap syndrome is not common in the general and hospital population (range: 1.0-3.6%), but is highly prevalent in patients diagnosed with either obstructive sleep apnea (range: 7.6-55.7%) or COPD (range: 2.9-65.9%). Overlap syndrome patients have been shown to have greater nocturnal oxygen desaturation (NOD) (i.e., reduced mean peripheral capillary oxygen saturation (SpO2) and increased sleep time spent with SpO2 < 90% (T90)) and worse sleep quality than patients with only OSA. It is associated with more frequent cardiovascular morbidity, poorer quality of life (QoL), more frequent COPD exacerbation and increased medical costs. This systematic review on overlap syndrome highlights the limitations and knowledge gaps of its prevalence, etiology and underlying pathophysiologic mechanisms related to increased morbidity and mortality.

Prevalence of obstructive sleep apnea in the general population: A systematic review.

With this systematic review we aimed to determine the prevalence of obstructive sleep apnea (OSA) in adults in the general population and how it varied between population sub-groups. Twenty-four studies out of 3807 found by systematically searching PubMed and Embase databases were included in this review. Substantial methodological heterogeneity in population prevalence studies has caused a wide variation in the reported prevalence, which, in general, is high. At ≥5 events/h apnea-hypopnea index (AHI), the overall population prevalence ranged from 9% to 38% and was higher in men. It increased with increasing age and, in some elderly groups, was as high as 90% in men and 78% in women. At ≥15 events/h AHI, the prevalence in the general adult population ranged from 6% to 17%, being as high as 49% in the advanced ages. OSA prevalence was also greater in obese men and women. This systematic review of the overall body of evidence confirms that advancing age, male sex, and higher body-mass index increase OSA prevalence. The need to a) consider OSA as having a continuum in the general population and b) generate consensus on methodology and diagnostic threshold to define OSA so that the prevalence of OSA can be validly compared across regions and countries, and within age-/sex-specific subgroups, is highlighted.