Pathophysiology of Obstructive Sleep Apnea in Aging Women

The common link between sleep apnea syndrome and osteoarthritis: a literature review

Patients with Osteoarthritis (OA) often also suffer from Sleep Apnea Syndrome (SAS), and many scholars have started to notice this link, although the relationship between the two is still unclear. In this review, we aim to summarize the current literature on these two diseases, integrate evidence of the OA and OSA connection, explore and discuss their potential common mechanisms, and thus identify effective treatment methods for patients with both OA and SAS. Some shared characteristics of the two conditions have been identified, notably aging and obesity as mutual risk factors. Both diseases are associated with various biological processes or molecular pathways, including mitochondrial dysfunction, reactive oxygen species production, the NF-kB pathway, HIF, IL-6, and IL-8. SAS serves as a risk factor for OA, and conversely, OA may influence the progression of SAS. The effects of OA on SAS are underreported in the literature and require more investigation. To effectively manage these patients, timely intervention for SAS is necessary while treating OA, with weight reduction being a primary requirement, alongside combined treatments such as Continuous positive airway pressure (CPAP) and medications. Additionally, numerous studies in drug development are now aimed at inhibiting or clearing certain molecular pathways, including ROS, NF-KB, IL-6, and IL-8. Improving mitochondrial function might represent a viable new strategy, with further research into mitochondrial updates or transplants being essential.

Racial differences in upper airway collapsibility and loop gain in young adult males

STUDY OBJECTIVES

Previous studies reported that the apnea-hypopnea index was similar in young adult Black and White participants. However, whether this similarity reflects an analogous combination of apneas and hypopneas is unknown. Likewise, the physiological mechanisms underlying this similarity has not been explored.

METHODS

60 Black and 48 White males completed the study. After matching for age and body mass index, 41 participants remained in each group. All participants completed a sleep study. Subsequently, standard sleep indices along with loop gain and the arousal threshold were determined. In addition, airway collapsibility (24 of 60 and 14 of 48 participants) and the hypoxic ventilatory response during wakefulness (30 of 60 and 25 of 48 participants) was measured.

RESULTS

The apnea-hypopnea index was similar in Blacks and Whites (p = .140). However, the index was comprised of more apneas (p = .014) and fewer hypopneas (p = .025) in Black males. These modifications were coupled to a reduced loop gain (p = .0002) and a more collapsible airway (p = .030). These differences were independent of whether or not the groups were matched. For a given hypoxic response, loop gain was reduced in Black compared to White males (p = .023).

CONCLUSIONS

Despite a similar apnea-hypopnea index, more apneas and fewer hypopneas were evident in young adult Black compared to White males. The physiological mechanisms that contribute to these events were also different between groups. Addressing these differences may be important when considering novel therapeutic approaches to eliminate apnea in Black and White participants.

Metabolomic approach for obstructive sleep apnea in adults: a systematic review

Obstructive Sleep Apnea (OSA) corresponds to episodes of complete or partial upper airway obstruction during sleep. The gold standard for diagnosing OSA is polysomnography; however, metabolomics is an innovative and highly sensitive method that seeks to identify and quantify small molecules in biological systems. Identify the metabolites most frequently associated with obstructive sleep apnea in adults. The search for articles was conducted between October 2020 and August 2021, in electronic databases, such as MEDLINE/PubMed, Scielo, Embase, and Cochrane, through the combination of descriptors: obstructive sleep apnea, metabolomic, adult. This systematic review included all cross-sectional studies published, including human patients aged 18 years or older, of both genders who underwent type I or II polysomnography and metabolomics study. The search strategy selected 3697 surveys, and 4 of them were selected to be a part of this systematic review. Based on the analyzed surveys, it was found that all of them were able to diagnose OSA, reaching a sensitivity of 75-97%, and specificity that ranged from 72 to 100%; besides differentiating patients with OSA (severe, moderate, and mild) from simple snorers with a mean sensitivity of 77.2% and specificity of 66.25%. These findings suggest that, in addition to being used as a screening and diagnostic strategy for OSA, metabolomics has the potential to be used for severity stratification and to monitor the disease's progression.

Oxygen resaturation rate is significantly associated with objectively assessed excessive daytime sleepiness in suspected obstructive sleep apnoea patients

INTRODUCTION

Commonly utilised metrics such as the apnoea-hypopnoea index show limited correlation to excessive daytime sleepiness (EDS). Oxygen desaturation parameters show better predictive power, however oxygen resaturation parameters have not yet been investigated. Oxygen resaturation may represent increased cardiovascular fitness and thus we hypothesized that a higher resaturation rate would be protective against EDS.

METHODS

Oxygen saturation parameters were computed via ABOSA software for adult patients referred for polysomnography and multiple sleep latency test in Israel Loewenstein hospital 2001-2011. EDS was defined as a mean sleep latency (MSL) below 8 min.

RESULTS

1629 patients (75% male, 53% obese, median age of 54 years) were included for analysis. The average desaturation event nadir was 90.4% and resaturation rate 0.59%/second. Median MSL was 9.6 min, and 606 patients met criteria for EDS. Patients who were younger, female, and with larger desaturations had significantly higher resaturation rates (p < 0.001). In multivariate models, adjusted for age, sex, body mass index, and average desaturation depth, resaturation rate showed a significant negative correlation with MSL (z-score standardised beta, -1 (95%CI -0.49, -1.52)), and significantly increased odds ratio (OR) of EDS (OR, 1.28 (95%CI 1.07, 1.53)). The beta associated with resaturation rate was larger, though non-significantly, than that of desaturation depth (difference 0.36 (95% CI -1.34, 0.62), p = 0.470).

CONCLUSION

Oxygen resaturation parameters show significant associations with objectively assessed EDS independent of desaturation parameters. Thus, resaturation and desaturation parameters may reflect differing underlying mechanistic pathways and both be considered novel and appropriate markers for assessing sleep-disordered breathing and associated outcomes.

Menopause Is Associated with Obstructive Sleep Apnea in a Population-Based Sample from Mecklenburg–Western Pomerania, Germany

Objective: Menopause is associated with multiple health risks. In several studies, a higher incidence or a higher risk for obstructive sleep apnea (OSA) in post-menopausal than pre-menopausal women is reported. This study was designed to verify such a connection between menopause and OSA in a population-based sample. Methods: For a subsample (N = 1209) of the Study of Health in Pomerania (N = 4420), complete polysomnography data was available. Of these, 559 females completed a structured interview about their menstrual cycle. Splines and ordinal regression analysis were used to analyze the resulting data. Results: In the ordinal regression analysis, a significant association between the apnea–hypopnea index (AHI) and menopause indicated that post-menopausal women had a substantially higher risk of OSA. In accordance with previous studies, risk indicators such as body mass index (BMI), age, and the influence of hysterectomies or total oophorectomies were included in the model. Conclusions: Our results clearly confirmed the assumed connection between menopause and OSA. This is important because OSA is most often associated with male patients, and it warrants further research into the underlying mechanisms.

Duration of respiratory events in obstructive sleep apnea: Factors influencing the duration of respiratory events

Several factors influence respiratory event duration during sleep. In general, women have shorter respiratory events compared to men as it appears that women have a more reactive upper airway contributing to the occurrence of short events. In addition, the increased amount of adipose tissue in the upper airways should make the reopening of the upper airways more difficult, leading to long respiratory events. Nevertheless, an increase in body mass index decreases the median duration of apneas, hypopneas, and desaturations in all OSA severity categories. Also, respiratory events are longer in older adults compared to younger ones, and the most likely mechanism explaining this phenomenon appears to be the increased circulatory delay associated with aging. Several studies have also shown that apnea events are longer in rapid eye movement sleep compared to non-rapid eye movement sleep. The main mechanism behind these differences appears to be the greater pharyngeal muscle relaxation during rapid eye movement sleep. Finally, sleeping position affects the duration of respiratory events; apneas and hypopneas are longer in the supine compared to lateral postures regardless of the severity of OSA. In the present report, we discuss the best-known factors influencing the duration of abnormal breathing events during sleep.

Change in the Constricted Airway in Patients after Clear Aligner Treatment: A Retrospective Study

This retrospective study evaluated changes in the pharyngeal portion of the upper airway in patients with constricted and normal airways treated with clear aligners (Invisalign, Align). Additionally, we assessed the change of tongue position in the oral cavity from a lateral view. Evaluation was performed with specialized software (Invivo 6.0, Anatomage) on pretreatment and post-treatment pairs of cone beam computed tomography imaging (CBCT) data. The level of airway constriction, volume, cross-section minimal area and tongue profile were evaluated. Patients with malocclusion, with pair or initial and finishing CBCT and without significant weight change between the scans, treated with Invisalign clear aligners were distributed into two groups. Group A consisted of fifty-five patients with orthodontic malocclusion and constricted upper airway. Control group B consisted of thirty-one patients with orthodontic malocclusions without any airway constriction. In the group with airway constriction there was a statistically significant increase in volume during therapy (p < 0.001). The surface of the most constricted cross-section of the airway did not change significantly after treatment in any of the groups. The final tongue position was different from the initial position in 62.2% of all clear aligner treatments. The position of the smallest clearance of the airway in the pharynx was similar for both groups localized at the level of 2nd cervical vertebra.