Effect of obstructive sleep apnoea on diabetic retinopathy and maculopathy: a systematic review and meta-analysis

No bidirectional relationship between sleep phenotypes and risk of proliferative diabetic retinopathy: a two-sample Mendelian randomization study

This study aimed to investigate the probable existence of a causal relationship between sleep phenotypes and proliferative diabetic retinopathy (PDR). Single nucleotide polymorphisms associated with sleep phenotypes were selected as instrumental variables at the genome-wide significance threshold (P < 5 × 10-8). Inverse-variance weighted was applied as the primary Mendelian randomization (MR) analysis method, and MR Egger regression, weighted median, simple mode, and weighted mode methods were used as complementary analysis methods to estimate the causal association between sleep phenotypes and PDR. Results indicated that genetically predicted sleep phenotypes had no causal effects on PDR risk after Bonferroni correction (P = 0.05/10) [Chronotype: P = 0.143; Daytime napping: P = 0.691; Daytime sleepiness: P = 0.473; Insomnia: P = 0.181; Long sleep duration: P = 0.671; Morning person:P = 0.113; Short sleep duration: P = 0.517; Obstructive sleep apnea: P = 0.091; Sleep duration: P = 0.216; and snoring: P = 0.014]. Meanwhile, there are no reverse causality for genetically predicted PDR on sleep phenotypes [Chronotype: P = 0.100; Daytime napping: P = 0.146; Daytime sleepiness: P = 0.469; Insomnia: P = 0.571; Long sleep duration: P = 0.779; Morning person: P = 0.040; Short sleep duration: P = 0.875; Obstructive sleep apnea: P = 0.628; Sleep duration: P = 0.896; and snoring: P = 0.047]. This study's findings did not support the causal effect of between sleep phenotypes and PDR. Whereas, longitudinal studies can further verify results validation.

The Role of Obstructive Sleep Apnea in Vision-Threatening Diabetic Retinopathy-A National Register-Based Study

INTRODUCTION

we investigated the association between OSA and vision-threatening diabetic retinopathy (VTDR).

METHODS

we used three nationwide registers to identify subjects with and without OSA and patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM). The Danish Civil Registration System was used to link OSA with diabetes diagnosis. The primary outcome was the occurrence of VTDR in diabetic patients with and without OSA. The secondary outcome was the prevalence of diabetes mellitus in patients with and without OSA.

RESULTS

we included 532,828 diabetic subjects comprising 13,279 patients with OSA (2.5%) and 519,549 without OSA (97.5%). Diabetic patients with OSA had a 57% lower risk of VTDR compared to diabetic patients without OSA (OR 0.43, 95% CI 0.38-0.50, p < 0.0001).

CONCLUSIONS

our findings indicate that OSA is associated with a lower risk of VTDR. Since we did not adjust our outcomes for diabetes duration, hypertension control and hemoglobin A1c, future studies are needed to confirm our findings.

Impact of obstructive sleep apnea on the expression of inflammatory mediators in diabetic macular edema

PURPOSE

To determine differences in inflammatory markers expressed in diabetic macular edema (DME) patients with and without obstructive sleep apnea (OSA).

METHODS

This was a prospective, cross-sectional study. Patients with treatment naive DME were enrolled in the study. They were stratified into 2 groups based on Apnea Hypopnea Index (AHI) from overnight polysomnography: OSA + (AHI ≥ 15) and OSA - (AHI<15). Multiplex immunoassay was performed for aqueous and serum cytokines including VEGF, placental growth factor (PGF), ICAM, IL2, IL3, IL6, IL8, IL10, IL17, vascular cell adhesion molecule-1 (VCAM1), monocyte attractant protein-1 (MCP1), epidermal growth factor (EGF) and platelet derived growth factor (PDGF). Statistical significance was defined as p < 0.004 using Bonferroni correction.

RESULTS

32 DME positive patients were enrolled in the study; of which 17 patients were OSA + and 15 OSA-. The OSA + cohort had significantly higher levels of serum EGF (p = 0.003), and trended towards higher levels of most serum cytokines including ICAM and IL6. OSA- cohort had significantly higher levels of aqueous IL17 compared to the OSA + cohort (2.97 ± 1.7 vs. 1.4 ± 0.46 pg/mL, p = 0.004). There were no significant differences in other aqueous cytokines.

CONCLUSIONS

OSA + group trended towards higher levels of most serum inflammatory markers, suggesting a greater pro-inflammatory state. However, they did not have significantly greater level of aqueous cytokines.

Retinal abnormalities, although relatively common in sleep clinic patients referred for polysomnography, are largely unrelated to sleep-disordered breathing

Study objectives.

There has been long-standing interest in potential links between obstructive sleep apnea (OSA) and eye disease. This study used retinal photography to identify undiagnosed retinal abnormalities in a cohort of sleep clinic patients referred for polysomnography (PSG) and then determined associations with PSG-quantified sleep-disordered breathing (SDB) severity.

Methods

Retinal photographs (n = 396 patients) were taken of each eye prior to polysomnography and graded according to validated, standardized, grading scales. SDB was quantified via in-laboratory polysomnography (PSG; n = 385) using standard metrics. A questionnaire (n = 259) documented patient-identified pre-existing eye disease. Within-group prevalence rates were calculated on a per patient basis. Data were analyzed using multivariate logistic regression models to determine independent predictors for retinal abnormalities. P < 0.05 was considered significant.

Results

Main findings were (1) 76% of patients reported no pre-existing “eye problems”; (2) however, 93% of patients had at least one undiagnosed retinal photograph-identified abnormality; (3) most common abnormalities were drusen (72%) and peripapillary atrophy (PPA; 47%); (4) age was the most common risk factor; (5) diabetes history was an expected risk factor for retinopathy; (6) patients with very severe levels of SDB (apnea hypopnea index ≥ 50 events/h) were nearly three times more likely to have PPA.

Conclusion

Retinal photography in sleep clinic settings will likely detect a range of undiagnosed retinal abnormalities, most related to patient demographics and comorbidities and, except for PPA, not associated with SDB. PPA may be indicative of glaucoma, and any association with severe SDB should be confirmed in larger prospective studies.

Effect of obstructive sleep apnoea on retinal microvascular function: a randomised controlled trial

PURPOSE

Retinal microvascular endothelial dysfunction is thought to be of importance in the development of ocular vascular diseases. Obstructive sleep apnoea (OSA) causes macrovascular endothelial dysfunction, but the effect of OSA on retinal microvascular endothelial function is not known. We aimed to determine the effect of OSA on retinal microvascular function.

METHODS

We conducted a multi-centre, double-blind, randomised, parallel, controlled trial in patients with known moderate-to-severe OSA, established on continuous positive airway pressure (CPAP). Participants were randomised to 14 nights of either continued CPAP or sham CPAP to generate a return of OSA. Retinal vascular responses to flickering light were measured using dynamic vessel analysis both at baseline and after 14 nights of intervention. The primary outcome was the change from baseline to follow-up in the area under the curve of the arteriolar response to flickering light, sham CPAP versus continued CPAP.

RESULTS

Nineteen patients were randomised to sham CPAP, and 18 patients were randomised to continued CPAP. There was no significant effect of CPAP withdrawal and return of OSA on retinal responses, with a change in the area under the curve of the arteriole response to flickering light of + 3.8 arbitrary units (95% CI - 10.6 to + 18.2, p = 0.59), sham CPAP versus continued CPAP.

CONCLUSIONS

CPAP withdrawal and a return of OSA had no significant effect on retinal microvascular responses. This contrasts with the effect of CPAP withdrawal on macrovascular endothelial function and suggests that OSA has different effects on macrovascular and microvascular endothelial function. ISRCTN 78082983, 23/10/2014, Prospectively registered.

Starting Time of Presbyopic Eyeglasses Wear and Lifestyle

Purpose

Presbyopia is a serious burden in the aged population, however, the factors affecting its progression have not been fully determined. The aim of this study was to explore the association between the time of starting to wear presbyopic eyeglasses and lifestyle, in participants aged from 40 to 59 years.

Methods

We selected the sample to be representative of sex and age for the age group 40 to 59 years. Participants completed a web-based survey on presbyopia-related questions, symptomatic dry eye, sleep habits, Pittsburgh Sleep Quality Index, subjective happiness scale (SHS), and other lifestyle-related questions including marital status, income, screen time, sun exposure, family history of myopia, and the frequency of regular visits to medical services.

Results

We found 529 participants (26.5%) used near correction, with a mean age for first near correction of 47.8±4.8 years. An earlier commencement of near correction correlated with hyperopia (P = 0.013), late wake-up time (P = 0.010), a poor subjective sleep quality score (P = 0.019), and a low annual income score (P = 0.025), after adjusting for age and sex. Stratification by income demonstrated the low-income group exhibited more dry eye, later wake-up time, longer sleep latency, longer sleep duration, worse sleep efficacy, lower SHS score, and a higher prevalence of living alone compared with the high-income group. The usage of corrective devices did not differ between the two groups.

Conclusions

The current study suggests a healthy sleep habit may delay the need for near correction, in addition to myopia. Shift work and circadian rhythm disruption might exacerbate presbyopia progression.

Intermittent hypoxia is involved in gut microbial dysbiosis in type 2 diabetes mellitus and obstructive sleep apnea-hypopnea syndrome

BACKGROUND

Obstructive sleep apnea (OSA)-hypopnea syndrome (OSAHS) has been recognized as a comorbidity of type 2 diabetes mellitus (T2DM); more than half of T2DM patients suffer from OSAHS. Intermittent hypoxia (IH) plays an important role in metabolic diseases, such as obesity and OSAHS, through various mechanisms, including altering the gut microecological composition and function. Therefore, it is important to study the role of gut microbiota in T2DM patients with OSAHS, which has a high incidence and is prone to several complications.

AIM

To assess whether IH is involved in altering the fecal microbiome in T2DM patients with OSAHS.

METHODS

Seventy-eight participants were enrolled from Henan Province People’s Hospital and divided into healthy control (HC, n = 26), T2DM (n = 25), and T2DM + OSA (n = 27) groups based on their conditions. The fecal bacterial DNA of the research participants was extracted and subjected to 16S ribosomal RNA sequencing. The clinical indices, such as insulin resistance index, homocysteine (HCY) concentration, and the concentrations of inflammatory factors in the peripheral blood, were assessed and recorded.

RESULTS

Group T2DM + OSA had the highest apnea-hypopnea index (AHI) (2.3 vs 3.7 vs 13.7), oxygen desaturation index (0.65 vs 2.2 vs 9.1), HCY concentration (9.6 μmol/L vs 10.3 μmol/L vs 13.81 μmol/L) and C-reactive protein (CRP) concentrations (0.3 mg/L vs 1.43 mg/L vs 2.11 mg/L), and lowest mean oxygen saturation (97.05% vs 96.6% vs 94.7%) among the three groups. Twelve and fifteen key differences in amplicon sequence variants were identified when comparing group T2DM + OSA with groups T2DM and HC, respectively. We found progressively decreased levels of Faecalibacterium, Eubacterium, and Lachnospiraceae, and an increase in the level of Actinomyces, which strongly correlated with the HCY, CRP, fasting plasma glucose, and hemoglobin A1c concentrations, AHI, mean oxygen saturation, and insulin resistance index in group T2DM + OSA (P < 0.05).

CONCLUSION

For T2DM patients with OSAHS, IH may be involved in selective alterations of the gut microbiota, which may affect the pathophysiological development of T2DM and DM-related complications.

Sleep and eye disease: A review

There is a growing body of literature on the effects of sleep disorders, in particular obstructive sleep apnoea (OSA), on ocular health, with consistent evidence of an increased risk of floppy eyelid syndrome, non-arteritic anterior ischaemic optic neuropathy, diabetic macular oedema, and other retinal vasculature changes in individuals with OSA. However, reports on OSA's associations with glaucoma, papilloedema, diabetic retinopathy, central serous chorioretinopathy, and keratoconus have been conflicting, while links between OSA and age-related macular degeneration have only been described fairly recently. Despite numerous suggestions that OSA treatment may reduce risk of these eye diseases, well-designed studies to support these claims are lacking. In particular, the ocular hypertensive effects of continuous positive airway pressure (CPAP) therapy for OSA requires further investigation into its potential impact on glaucoma risk and management. Reports of ocular surface complications secondary to leaking CPAP masks highlights the importance of ensuring good mask fit. Poor sleep habits have also been linked with increased myopia risk; however, the evidence on this association remains weak.

Sleep apnea and eye diseases: evidence of association and potential pathogenic mechanisms

Eye diseases are an important group of increasingly prevalent disorders that contribute very significantly to disability and represent a considerable health burden. Some data suggest that several of these diseases may be associated with sleep-disordered breathing, mainly obstructive sleep apnea (OSA), due to intermediate mechanisms, such as intermittent hypoxia or sleep fragmentation. The aims of this systematic review were to identify and critically evaluate the current evidence supporting the existence of a possible relationship between OSA and the more relevant eye diseases as well as to evaluate the potential pathogenic mechanisms. There is a body of largely low-level evidence for the association of OSA with glaucoma, nonarteritic ischemic optic neuropathy, central serous chorioretinopathy, and diabetic retinopathy. Meta-analysis of available case-control studies shows that OSA increases the risk of glaucoma (pooled odds ratio: 1.50; 95% confidence interval: 1.25 to 1.80; P < .001), nonarteritic ischemic optic neuropathy (3.62; 1.94 to 6.76; P < .001), and diabetic retinopathy (1.57; 1.09 to 2.27; P = .02). Moreover, several pathogenic pathways have been identified, mainly related to hypoxic damage, mechanical stress, systemic inflammation, oxidative stress, sympathetic tone, and endothelial dysfunction. In contrast, information about the effect of apnea-hypopnea suppression on the development and progression of eye damage is either nonexistent or of a very low level of evidence. In conclusion, OSA has emerged as an additional potential risk factor for many eye diseases, although their link is weak and contradictory, so further examination is required.

CITATION

García-Sánchez A, Villalaín I, Asencio M, García J, García-Rio F. Sleep apnea and eye diseases: evidence of association and potential pathogenic mechanisms. J Clin Sleep Med. 2022;18(1):265-278.

Obstructive Sleep Apnoea, Other Sleep Parameters and Diabetic Retinopathy

PURPOSE OF REVIEW

To summarise the association between obstructive sleep apnoea and diabetic retinopathy and diabetic macular oedema. To examine the effects of other sleep parameters on diabetic retinopathy and diabetic macular oedema. To discuss the pathophysiology of diabetic eye changes and how it is related to obstructive sleep apnoea.

RECENT FINDINGS

Conflicting data exists in terms of the association of diabetic eye changes with sleep apnoea and/or other sleep parameters. Various cross-sectional studies show PDR to be associated with the prevalence of OSA. Patients who underwent continuous positive airway pressure (CPAP) treatment were significantly less likely to develop pre/proliferative DR. Secondary sleep parameters generally are not associated with DR except for long duration of sleep. Differences in reporting could be due to the different thresholds set to define OSA/ODI and severity of DR/DME, in addition to factors used in multivariate analysis. There is a need for further studies with long-term follow-up and to assess the impact of CPAP on the development and progression of diabetic eye change(s).

The Association Between Obstructive Sleep Apnea and Cotton-Wool Spots in Nonproliferative Diabetic Retinopathy

Purpose:

This work reports the association of obstructive sleep apnea (OSA) and cotton-wool spots (CWS) seen in patients with nonproliferative diabetic retinopathy (DR).

Methods:

A random sample of patients diagnosed with DR between January 1, 2015 and December 31, 2018, were selected from medical-billing codes. Dilated funduscopic examination findings and medical history were analyzed by reviewing medical records.

Results:

CWS were present in 12 of 118 patients without OSA, compared with 11 of 32 patients with OSA (10.2% vs 34.4%, respectively; P = .002). OSA was more common in men (68.8%, P = .03) and associated with a higher body mass index (30.0 ± 5.0 without OSA vs 33.6 ± 5.5 with OSA, P < .001). When comparing those with and without OSA, there was no association with age; glycated hemoglobin A1c; stage of DR; insulin dependence; presence of diabetic macular edema; smoking status; or a history of hypertension, hyperlipidemia, cardiovascular disease, or other breathing disorder.

Conclusions:

The presence of OSA is associated with CWS in patients with DR, as well as male sex and a higher body mass index. Further research is needed to determine the ophthalmologist’s role in the timely referral of patients with CWS for OSA evaluation.

Screening for obstructive sleep apnea in a diabetic retinopathy clinic in a tertiary care center

Purpose:

To screen for obstructive sleep apnea (OSA) in patients presenting to diabetic retinopathy (DR) clinic and to correlate its presence with the severity of DR.

Methods:

A prospective, cross-sectional study of diabetes mellitus patients in retina clinic of a tertiary care referral center, North India (January 2019–March 2020). All were subjected to STOP-Bang Questionnaire and Epworth Sleepiness Scale (ESS) score. Patients at high OSA risk (STOP-Bang score ≥5 and ESS score ≥10) were referred to Department of Otorhinolaryngology (sleep clinic) for polysomnography. Based on Apnea Hypopnea Index (AHI), OSA was graded as mild (AHI = 5–14/h), moderate (AHI = 15–30/h), and severe (AHI >30/h). Statistical analysis was done using three models of outcome measures: (1) “No DR” versus “any DR,” (2) “Less severe DR” versus “More severe DR,” and (3) “No diabetic macular edema (DME)” versus “DME.”

Results:

Of 362 patients screened, 18 (4.97%) had OSA (11 mild, 5 moderate, and 2 severe). Though OSA did not show a significant association with various outcome measures, patients with moderate–severe OSA had higher odds in developing “any DR” (OR = 7.408; 95% CI = 0.533–102.898), “more severe DR” (OR = 1.961; 95% CI = 0.153–25.215), and “DME” (OR = 2.263; 95% CI = 0.357–14.355), on multiple logistic regression.

Conclusion:

Ours is the first screening study of OSA in DR patients in India, the diabetes capital of the world. We detected OSA in 4.97% of patients in a DR clinic, with an increased risk of “any DR,” “more severe DR,” and “DME” in the presence of moderate–severe OSA.

Possible Preventative/Rehabilitative Role of Gliflozins in OSA and T2DM. A Systematic Literature Review-Based Hypothesis

Obstructive sleep apnoea (OSA) is characterized by frequent apnoea episodes during sleep due to upper airway obstruction. The present review summarizes current knowledge on inter-relationships between OSA and type 2 diabetes mellitus (T2DM) and suggests the former as a possible target for sodium-glucose co-transporter-2 inhibitors (SGLT-2i). Based on pathophysiological mechanisms underlying OSA onset and renal SGLT-2 effects, we suggest that SGLT-2i indications might expand beyond current ones, including glucose, lipids, uric acid, blood pressure, and body weight control as well as chronic heart failure and kidney disease prevention.

Ocular Complications of Obstructive Sleep Apnea

Obstructive sleep apnea (OSA), the most common form of sleep-disordered breathing, is characterized by repetitive episodes of paused breathing during sleep, which in turn induces transient nocturnal hypoxia and hypercapnia. The high prevalence of OSA and its associated health consequences place a heavy burden on the healthcare system. In particular, the consequent episodic oxygenic desaturation/reoxygenation series and arousals from sleep in patients with OSA have the potential to trigger oxidative stress, elevated systemic inflammatory responses, and autonomic dysfunction with sympathetic activation. Given these adverse side-effects, OSA is highly correlated to many eye diseases that are common in everyday ophthalmic practices. Some of these ocular consequences are reversible, but they may permanently threaten a patient’s vision if not treated appropriately. Here, this article seeks to review the ocular consequences and potential pathophysiologic associations in patients with OSA. Understanding these OSA-related eye diseases may help clinicians provide comprehensive care to their patients.

The Associations of Obstructive Sleep Apnea and Eye Disorders: Potential Insights into Pathogenesis and Treatment

Purpose of Review

Obstructive sleep apnea (OSA) patients are at significantly increased risks for cardiovascular and cerebrovascular morbidities. Recently, there has been heightened interest in the association of OSA with numerous ocular diseases and possible improvement of these conditions with the initiation of OSA treatment. We reviewed the current evidence with an emphasis on the overlapping pathogeneses of both diseases.

Recent Findings

Currently available literature points to a substantial association of OSA with ocular diseases, ranging from those involving the eyelid to optic neuropathies and retinal vascular diseases. Since the retina is one of the highest oxygen-consuming tissues in the body, the intermittent hypoxia and hypercapnia ensuing in OSA can have deleterious effects on ocular function and health. Tissue hypoxia, autonomic dysfunction, microvascular dysfunction, and inflammation all play important roles in the pathogenesis of both OSA and ocular diseases. Whether OSA treatment is capable of reversing the course of associated ocular diseases remains to be determined. It is anticipated that future therapeutic approaches will target the common underlying pathophysiologic mechanisms and promote favorable effects on the treatment of known associated ocular diseases.

Summary

Emerging evidence supports the association of ocular diseases with untreated OSA. Future studies focusing on whether therapeutic approaches targeting the common pathophysiologic mechanisms will be beneficial for the course of both diseases are warranted.

Genome-wide polygenic risk score for retinopathy of type 2 diabetes

Diabetic retinopathy (DR) is a common consequence in type 2 diabetes (T2D) and a leading cause of blindness in working-age adults. Yet, its genetic predisposition is largely unknown. Here, we examined the polygenic architecture underlying DR by deriving and assessing a genome-wide polygenic risk score (PRS) for DR. We evaluated the PRS in 6079 individuals with T2D of European, Hispanic, African and other ancestries from a large-scale multi-ethnic biobank. Main outcomes were PRS association with DR diagnosis, symptoms and complications, and time to diagnosis, and transferability to non-European ancestries. We observed that PRS was significantly associated with DR. A standard deviation increase in PRS was accompanied by an adjusted odds ratio (OR) of 1.12 [95% confidence interval (CI) 1.04-1.20; P = 0.001] for DR diagnosis. When stratified by ancestry, PRS was associated with the highest OR in European ancestry (OR = 1.22, 95% CI 1.02-1.41; P = 0.049), followed by African (OR = 1.15, 95% CI 1.03-1.28; P = 0.028) and Hispanic ancestries (OR = 1.10, 95% CI 1.00-1.10; P = 0.050). Individuals in the top PRS decile had a 1.8-fold elevated risk for DR versus the bottom decile (P = 0.002). Among individuals without DR diagnosis, the top PRS decile had more DR symptoms than the bottom decile (P = 0.008). The PRS was associated with retinal hemorrhage (OR = 1.44, 95% CI 1.03-2.02; P = 0.03) and earlier DR presentation (10% probability of DR by 4 years in the top PRS decile versus 8 years in the bottom decile). These results establish the significant polygenic underpinnings of DR and indicate the need for more diverse ancestries in biobanks to develop multi-ancestral PRS.

Inverse Cross-sectional and Longitudinal Relationships between Diabetic Retinopathy and Obstructive Sleep Apnea in Type 2 Diabetes

Purpose

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Systematic review of clinical practice guidelines to identify recommendations for sleep in type 2 diabetes mellitus management

INTRODUCTION

Sleep quality, quantity and timing have been shown to impact glycaemic control, with a role in insulin sensitivity, glucose tolerance and HbA1C levels, in both diabetic and non-diabetic populations. The aim of this study was to identify recommendations for sleep assessment and management in international clinical practice guidelines focused on type 2 diabetes mellitus management in adults.

STUDY DESIGN

Systematic Review.

METHODOLOGY

Clinical practice guidelines which focused on the management of type 2 diabetes mellitus in adults were included (n = 35). Two independent reviewers utilised the Appraisal of Guidelines for Research and Evaluation tool (AGREE) II and a third reviewer resolved any disagreements. Included guidelines were assessed for recommendations about sleep in diabetes management (n = 14). Data were extracted on sleep recommendations ,themes were generated from the extracted data and narrative syntheses were created.

RESULTS

From 1114 identified papers, 35 guidelines met the inclusion criteria. Fourteen of these guidelines included recommendations pertaining to sleep, which broadly fell into five categories; sleep assessment, sleep as a therapeutic target, sleep and co-morbidities of type 2 diabetes mellitus, shift work and sleep and driving. Recommendations varied across guidelines.

CONCLUSION

Few guidelines provided recommendations relating to assessment and management of sleep in type 2 diabetes care. Most of the recommendations were related to obstructive sleep apnoea. However, few guidelines discussed sleep as a therapeutic intervention for diabetes mellitus or described the potential importance of sleep quality and duration in glycaemic control. Prospero registration number: CRD42020142136.

Targeted Metabolomics Analysis on Obstructive Sleep Apnea Patients after Multilevel Sleep Surgery

BACKGROUND

Obstructive sleep apnea (OSA) is caused by partial or complete obstruction of the upper airways. Corrective surgeries aim at removing obstructions in the nasopharynx, oropharynx, and hypopharynx. OSA is associated with an increased risk of various metabolic diseases. Our objective was to evaluate the effect of surgery on the plasma metabolome.

METHODS

This study included 39 OSA patients who underwent Multilevel Sleep Surgery (MLS). Clinical and anthropometric measures were taken at baseline and five months after surgery.

RESULTS

The mean Apnea-Hypopnea Index (AHI) significantly dropped from 22.0 ± 18.5 events/hour to 8.97 ± 9.57 events/hour (p-Value < 0.001). Epworth's sleepiness Score (ESS) dropped from 12.8 ± 6.23 to 2.95 ± 2.40 (p-Value < 0.001), indicating the success of the surgery in treating OSA. Plasma levels of metabolites, phosphocholines (PC) PC.41.5, PC.42.3, ceremide (Cer) Cer.44.0, and triglyceride (TG) TG.53.6, TG.55.6 and TG.56.8 were decreased (p-Value < 0.05), whereas lysophosphatidylcholines (LPC) 20.0 and PC.39.3 were increased (p-Value < 0.05) after surgery.

CONCLUSION

This study highlights the success of MLS in treating OSA. Treatment of OSA resulted in an improvement of the metabolic status that was characterized by decreased TG, PCs, and Cer metabolites after surgery, indicating that the success of the surgery positively impacted the metabolic status of these patients.

Sleep disturbances: one of the culprits of obesity-related cardiovascular risk?

Growing evidence suggested that Sleep Disorders (SD) could increase the risk of developing obesity and could contribute to worsen obesity-related cardiovascular risk. Further, obesity per se has been reported to blunt sleep homeostasis. This happens through several mechanisms. First of all, the excessive adipose tissue at neck and chest levels could represent a mechanical obstacle to breathe. Moreover, the visceral adipose tissue is known to release cytokines contributing to low-grade chronic inflammation that could impair the circadian rhythm. Also, nutrition plays an important role in sleep homeostasis. High fat and/or high carbohydrate diets are known to have a negative impact on both sleep quality and duration. In addition, obesity predisposes to a condition called "obstructive sleep apnea" that has a detrimental effect on sleep. SD could increase the risk and/or could contribute to worsen cardiovascular risk usually associated with obesity. The chronic low grade inflammation associated with obesity has been reported to increase the risk of developing hypertension, type 2 diabetes and dyslipidemia. In turn, improving quality of sleep has been reported to improve the management of these cardiovascular risk factors. Thus, the aim of this manuscript is to provide evidence on the association of obesity and SD and on how they could contribute to the risk of developing cardiovascular risk factors such as hypertension, dyslipidemia and type 2 diabetes in obesity.

The Veterans Affairs Continuous Positive Airway Pressure Use and Diabetic Retinopathy Study

SIGNIFICANCE

Obstructive sleep apnea has been linked to the development and progression of diabetic retinopathy. In this study, diabetic patients compliant with continuous positive airway pressure therapy (CPAP) for sleep apnea were less likely to have retinopathy, emphasizing the benefits and potential therapeutic role of CPAP in individuals with both conditions.

PURPOSE

The aim of this study was to compare the prevalence of diabetic retinopathy in type 2 diabetic patients with obstructive sleep apnea who were compliant with CPAP therapy with those who were not compliant with CPAP therapy.

METHODS

A retrospective cross-sectional review of type 2 diabetic patients using CPAP for obstructive sleep apnea was conducted. The prevalence of retinopathy was identified, and groups with and without retinopathy were compared using univariate analyses and multivariate logistic regression.

RESULTS

The prevalence of retinopathy was 19.6% (n = 321). Retinopathy was significantly less prevalent in those compliant with CPAP (odds ratio, 0.54; 95% confidence interval, 0.31 to 0.94; P = .04). The relationship remained statistically significant when adjusting for other factors known to impact the course of diabetic eye disease.

CONCLUSIONS

Increased CPAP compliance may mitigate the risk of developing diabetic retinopathy in type 2 diabetic patients with obstructive sleep apnea.

Sleep-related disorders in patients with type 1 diabetes mellitus: current insights

Type 1 diabetes mellitus (T1DM) is an autoimmune condition that results from destruction of beta cells in the pancreas. Several reviews have concluded that sleep contributes to poor glycemic control, diabetes management, and diabetes-related complications in individuals with T1DM and represents an untapped opportunity for intervention. However, at the current juncture, the American Diabetes Association's Standards of Medical Care are devoid of recommendations about how to address sleep in the management of T1DM. This article summarizes reviews of sleep in youth and adults with T1DM and empirical studies that have examined various sleep parameters ranging from sleep disturbances (general, perceived sleep quality, sleepiness, awakenings, and sleep efficiency), sleep duration, sleep consistency, sleep-disordered breathing (SDB), and sleep architecture. The data show that many individuals with T1DM sleep less than recommendations; individuals with the poorest sleep have difficulties with diabetes management; and sleep deficiency including SDB often corresponds to several disease morbidities (neuropathy, nephropathy, etc). Mixed findings exist regarding direct associations of various sleep parameters and glycemic control. SDB appears to be just as prevalent, if not more, than other conditions that have been recommended for universal screening in individuals with T1DM. The article concludes with recommendations for collaborative research efforts to further elucidate the role of sleep in diabetes-related outcomes; investigations to test behavioral strategies to increase sleep quantity and consistency; and considerations for clinical care to address sleep.

The associations of objectively measured sleep duration and sleep disturbances with diabetic retinopathy

AIMS

To assess the associations between objectively measured sleep duration, sleep disturbances and diabetic retinopathy (DR).

METHODS

This cross-sectional study recruited 92 patients with diabetes from retinal clinics. Objective measurements of sleep duration, apnea-hypopnea index (AHI) and minimum oxygen saturations (SaO2) were obtained through polysomnography. The Epworth Sleepiness Scale and Insomnia Severity Index were administered. Retinal photographs were taken and graded according to the modified Airlie House Classification System. Regression analysis used to determine associations with outcomes including moderate DR, vision-threatening DR (VTDR) and diabetic macular edema (DME).

RESULTS

Mean age of participants was 57.6 ± 8.3 years. 29 (32%) of them had moderate DR, and 17 (18.5%) had VTDR. Higher AHI (Odds Ratio [OR] 1.04; 95% confidence interval [CI] 1.00, 1.07) and short sleep duration (OR 3.22; 95%CI 1.18, 8.79) were associated with moderate DR. VTDR was associated with moderate obstructive sleep apnea (OSA) (OR 4.73; 95%CI 1.46, 15.31), higher AHI (OR 1.06; 95%CI 1.02, 1.10) and lower minimum SaO2 (OR 0.89; 95%CI 0.83, 0.96). High risk for insomnia was associated with DME (OR 4.01; 95%CI 1.09, 14.73).

CONCLUSIONS

Short sleep duration was associated with moderate DR while OSA-related parameters and a high risk for insomnia were associated with moderate DR, VTDR and DME.

Apnea Hypopnea Index During Rapid Eye Movement Sleep With Diabetic Retinopathy in Patients With Type 2 Diabetes

CONTEXT

Recent studies based on home sleep apnea testing (HSAT) reported the potential association of sleep disordered breathing, such as obstructive sleep apnea (OSA), with diabetic retinopathy (DR). A few studies showed that the apnea-hypopnea index (AHI) during rapid eye movement (REM) sleep (REM-AHI) is associated with glycated hemoglobin and hypertension, two known risk factors for DR. However, there are no studies that have evaluated the association of REM-AHI with DR because previous studies were based on HSAT.

OBJECTIVE

To determine the association of REM-AHI with DR.

DESIGN, SETTING, AND PATIENTS

The study subjects were 131 patients with type 2 diabetes mellitus who underwent all-night polysomnography with ≥30 minutes of REM sleep and were free of heart failure or active lung disease and had not yet been treated for OSA. Logistic regression analysis was performed to determine the effect of REM-AHI on the prevalence of DR adjusted by several known risk factors for DR.

RESULTS

Quartile of REM-AHI was independently associated with DR (P = 0.024) (Q2: OR, 3.887; 95% CI, 0.737 to 20.495; Q3: OR, 9.467; 95% CI, 1.883 to 47.588; Q4: OR, 12.898; 95% CI, 2.008 to 82.823 relative to Q1), whereas quartile of non-REM (NREM)-AHI was not (P = 0.119). Similarly, continuous REM-AHI (OR, 2.875; 95% CI, 1.224 to 6.752; P = 0.015) was independently associated with DR, whereas NREM-AHI was not (P = 0.107). In addition, AHI was independently associated with DR when controlling for several known risk factors for DR (P = 0.043).

CONCLUSION

REM-AHI was independently associated with DR. REM-AHI could be a potential risk factor for DR.

Risk of Incident Obstructive Sleep Apnea Among Patients With Type 2 Diabetes

OBJECTIVE

This study compared the incidence of obstructive sleep apnea (OSA) in patients with and without type 2 diabetes and investigated risk factors for OSA in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A retrospective cohort study was performed to compare OSA incidence between adult patients with and without type 2 diabetes matched for age, sex, and BMI. Patients with a prevalent OSA diagnosis were excluded. The study cohort was derived from The Health Improvement Network (THIN), a U.K. primary care database, from 1 January 2005 to 31 December 2017.

RESULTS

There were 3,110 (0.88%) and 5,968 (0.46%) incident OSA cases identified in the 360,250 exposed and 1,296,489 unexposed patient cohorts, respectively. Adjusted incidence rate ratio (aIRR) of OSA in patients with type 2 diabetes compared with those without was 1.48 (95% CI 1.42-1.55; P < 0.001). In a multivariate regression analysis of patients with type 2 diabetes, significant predictors of OSA were diabetes-related foot disease (1.23 [1.06-1.42]; P = 0.005), being prescribed insulin in the last 60 days (1.58 [1.42-1.75]; P < 0.001), male sex (2.27 [2.09-2.46]; P < 0.001), being overweight (2.02 [1.54-2.64]; P < 0.001) or obese (8.29 [6.42-10.69]; P < 0.001), heart failure (1.41 [1.18-1.70]; P < 0.001), ischemic heart disease (1.22 [1.11-1.34]; P < 0.001), atrial fibrillation (1.23 [1.04-1.46]; P = 0.015), hypertension (1.32 [1.23-1.43]; P < 0.001), and depression (1.75 [1.61-1.91]; P < 0.001).

CONCLUSIONS

When considered alongside previous evidence, this study indicates that the association between type 2 diabetes and OSA is bidirectional. In addition to known predictors of OSA, diabetes-related foot disease and insulin treatment were identified as risk factors in patients with type 2 diabetes.

Sleep-Disordered Breathing Is a Stronger Risk Factor for Proliferative Diabetic Retinopathy than Metabolic Syndrome and the Number of Its Individual Components

PURPOSE

To evaluate whether the features of sleep-disordered breathing (SDB) are stronger independent factors for proliferative diabetic retinopathy (PDR) compared to the incidence of metabolic syndrome (MetS) and the number of its individual components.

METHODS

We studied a cross-sectional total of 132 patients with type 2 diabetes. Thirty-nine patients had non-proliferative diabetic retinopathy (NPDR) and 93 patients had PDR. Pulse oximetry was conducted, and the patients' mean oxygen saturation (mean SpO2%) and 4% oxygen desaturation index (4% ODI times/hour) were evaluated. We compared the SDB and MetS variables between the NPDR and PDR patients. A logistic regression analysis was used to determine the independent factors for the diagnosis of PDR.

RESULTS

The MetS diagnosis was made significantly more often in the PDR group (p = 0.04). The number of individual MetS components was significantly greater in the PDR group compared to the NPDR group (p = 0.01). The mean SpO2 of the NPDR group was not significantly different from that of the PDR group. The 4% ODI in the NPDR group was significantly lower than that in the PDR group (p = 0.01). The logistic regression analysis using the prevalence of MetS and the number of MetS components revealed that younger age and high 4%ODI value were independent factors contributing to the diagnosis of PDR.

CONCLUSION

Our findings confirmed that compared to MetS and the number of its individual components, SDB may be a factor contributing to the progression to PDR. However, further careful longitudinal validation studies are needed.

The Epidemiology of Sleep and Diabetes

PURPOSE OF REVIEW

To provide an overview of the mechanistic and epidemiologic evidence linking sleep-related exposures, such as short sleep duration, obstructive sleep apnea, shift work, and insomnia, with type 2 diabetes risk in adults.

RECENT FINDINGS

Both poor sleep habits and sleep disorders are highly prevalent among adults with type 2 diabetes. In observational studies, short sleep duration, obstructive sleep apnea, shift work, and insomnia are all associated with higher risk of incident type 2 diabetes and may predict worse outcomes in those with existing diabetes. However, interventional studies addressing sleep abnormalities in populations with or at high risk for type 2 diabetes are scarce. Although common sleep abnormalities are associated with risk of incident type 2 diabetes and worse prognosis in those with established diabetes, there are few randomized trials evaluating the impact of sleep-focused interventions on diabetes, making it difficult to determine whether the relationship is causal.

Association of obesity and risk of diabetic retinopathy in diabetes patients: A meta-analysis of prospective cohort studies

BACKGROUND

Diabetic retinopathy (DR) was considered to be a common complication of diabetes. The purpose of the current study was to investigate the potential association between obesity and DR risk by conducting a meta-analysis of prospective studies.

METHODS

A consummate literature search of PubMed, EMBASE, and web of science was conducted until July 2016. A total of 13 prospective cohort studies were included in this meta-analysis.

RESULTS

On meta-analysis of all the studies assessing DR risk, obesity was associated with a significant increase in DR incidence (relative risk [RR], 1.20; 95% confidence interval [CI], 1.01-1.43; I = 59.6%). When only proliferative DR (PDR) was considered, no significant association between obesity and risk of PDR was detected. Significant harmful effect was detected in type 2 diabetes mellitus (T2DM) group (RR, 1.40; 95% CI, 1.05-1.87; I = 67.6%) but not mixed group (RR, 1.04; 95% CI, 0.97-1.18; I = 0.00%). No significant publication bias was detected in the selected 13 studies.

CONCLUSION

Obesity was a risk factor for non-proliferative DR. However additional well-designed and well-conducted epidemiologic studies were required to deepen our understanding of the relation between obesity and DR.

Obstructive sleep apnoea and Type 2 diabetes mellitus: are they connected?

Obstructive sleep apnoea (OSA), a sleep-related breathing condition, is diagnosed based on a patient's apnoea-hypopnea index from a sleep study, and the presence or absence of symptoms. Diabetes mellitus (DM) and OSA share a significant common risk factor, obesity, with all three conditions contributing to the risk of developing cardiovascular diseases. The pathophysiological links between OSA and DM are still unclear, but intermittent hypoxia may be an important mechanism. More awareness of the possible link between OSA and DM is needed, given their increasing prevalence locally and worldwide. Continuous positive airway pressure is the standard treatment for OSA, while weight loss through dietary and lifestyle modifications is important to holistically manage patients with either condition. There is currently insufficient evidence to support the benefits of screening every diabetic patient for OSA. However, diabetic patients with symptoms suggestive of OSA should be referred to a sleep specialist for further evaluation.

Associations between sleep duration, sleep quality and diabetic retinopathy

Background

Abnormal durations of sleep have been associated with risk of diabetes. However, it is not clear if sleep duration is associated with diabetic retinopathy (DR).

Methods

In a cross-sectional study, we included 1,231 (Malay, n = 395; Indian, n = 836) adults (mean age 64.4 ± 9.0 years, 50.4% female) with diabetes from the second visit of two independent population-based cohort studies (2011–15) in Singapore. Self-reported habitual sleep duration was categorized as short (<6 h), normal (6≤ h <8), and long (≥8 h). Questionnaires were administered to detect risk of obstructive sleep apnea (OSA), excessive daytime sleepiness, and insomnia, all of which may indicate poor quality of sleep. The associations between sleep-related characteristics with moderate DR and vision-threatening DR (VTDR) were analysed using logistic regression models adjusted for potential confounders.

Results

Prevalence of moderate DR and VTDR in the study population were 10.5% and 6.3% respectively. The mean duration of sleep was 6.4 ± 1.5 h. Compared to normal sleep duration, both short and long sleep durations were associated with moderate DR with multivariable odds ratio (95% confidence interval) of 1.73 (1.03–2.89) and 2.17 (1.28–3.66) respectively. Long sleep duration (2.37 [1.16–4.89]), high risk of OSA (2.24 [1.09–4.75]), and excessive daytime sleepiness (3.27 [1.02–10.30]) were separately associated with VTDR.

Conclusion

Sleep duration had a U-shaped association with moderate DR; long sleep duration, excessive daytime sleepiness and high risk of OSA were positively associated with VTDR.

Obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is increasing in prevalence due to rising obesity. While OSA is a disorder primarily of the upper airway during sleep, its pathophysiological impact on other body systems is increasingly recognised. There has been interest in the prevalence of OSA in different ophthalmic conditions and possible causation has been postulated. As OSA is common, it can be expected that people with co-existent OSA will be found in any ophthalmic disease population studied. To determine with confidence the significance of finding patients with OSA in a particular cohort requires a well matched control group, ideally matched for age, obesity, gender and co-morbidities. Only if one can say with certainty that the prevalence of OSA is higher in a group with a particular co-existent ophthalmic disease can we begin to speculate about possible mechanisms for the overlap in these conditions. Possible mechanisms for how OSA might affect the eye are discussed in this review. The current literature is reviewed with respect to diabetic retinopathy, glaucoma, floppy eyelid syndrome, non-arteritic ischaemic optic neuropathy, keratoconus and AMD. Associations with OSA have been found, but robust prospective studies using multi-channel sleep studies to diagnose OSA are lacking. Gaps remain in the evidence and in our knowledge. It is hoped that this review will highlight the need for ophthalmologists to consider OSA in their patients. It also makes recommendations for future research, especially to consider whether therapies for OSA can also be effective for ophthalmic disorders.

The Relationship between Diabetes-Related Complications and Obstructive Sleep Apnea in Type 2 Diabetes

This study explored the relationship between obstructive sleep apnea (OSA) and the presence of any diabetes-related complications in type 2 diabetes and whether this was mediated by hypertension. Secondly, the relationship between OSA severity and estimated glomerular filtration rate (eGFR) was investigated. A total of 131 patients participated. OSA was diagnosed using a home monitor, and severity was measured by apnea-hypopnea index (AHI) and oxygen desaturation index (ODI). OSA was found in 75.6% of the participants, 40.5% with moderate-to-severe degree. Any diabetes-related complications (retinopathy, neuropathy, nephropathy, or coronary artery disease) were present in 55.5%, and 70.2% of the participants had hypertension. Mediation analysis indicated that, compared to those with mild or no OSA, those with moderate-to-severe OSA were 3.05 times more likely to have any diabetes-related complications and that this relationship was mediated by the presence of hypertension. After adjusting for confounders, ODI (B = -0.036, p = 0.041), but not AHI, was significantly associated with lower eGFR. In conclusion, moderate-to-severe OSA was related to the presence of any diabetes-related complications in type 2 diabetes, and the relationship was mediated by hypertension. The severity of intermittent hypoxia was associated with lower eGFR. Whether OSA treatment will delay or reduce diabetes-related complications should be investigated.

Relationship of Obstructive Sleep Apnoea with Diabetic Retinopathy: A Meta-Analysis

Until now, the relationship of obstructive sleep apnoea (OSA) with diabetic retinopathy (DR) was controversial. This meta-analysis was performed to obtain definitive conclusion on this topic. Relevant articles were searched on databases of Pubmed, Google Scholar, and Chinese National Knowledge Infrastructure (CNKI). The articles were selected according to inclusion and exclusion criteria. Odds ratio (OR) with 95% confidence interval (CI) was used to evaluate the relationship of OSA with risk of DR. I2 and P value were used to assess the presence of heterogeneity. I2 ≥ 50% or P < 0.05 indicated significant heterogeneity. Sensitivity analysis was performed to evaluate the robustness of pooled results. Begg's funnel plot and Egger's regression analysis were adopted to assess publication bias. 6 eligible studies were selected in the present meta-analysis. The pooled results indicated that OSA was significantly associated with increased risk of DR (OR = 2.01, 95% CI = 1.49-2.72). Subgroup analysis based on type of diabetes mellitus suggested that OSA was related to DR in both Type 1 and Type 2 diabetes mellitus. Sensitivity analysis demonstrated that pooled results were robust. No significant publication bias was observed (P = 0.128). The results indicate that OSA is related to increased risk of DR.

The association of obstructive sleep apnea and renal outcomes-a systematic review and meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to summarize the association of obstructive sleep apnea (OSA) with renal outcome.

METHODS

Our study followed the PRISMA guidelines. Two independent reviewers searched for relevant articles in the databases of Pubmed, the Web of Science and CENTRAL, and conducted study selection and quality assessment. A random-effect model was used to estimate the effects.

RESULTS

total of 1240 articles were initially identified (Pubmed = 568, Web of Science = 640, CENTRAL = 32). After removal of duplicate articles (n = 415) and irrelevant articles (n = 788), 37 were selected for full-text review, and 18 were finally included in the analysis. Overall, patients diagnosed with OSA were found to have a higher odds ratio (OR) of a poorer renal outcome, with a pooled OR of 1.77 (95% C.I.: 1.37–2.29). The significant association between OSA and a poorer renal outcome was not affected by the medical condition of diabetes mellitus (DM). In addition, we found that OSA was consistently associated with higher albuminuria/proteinuria and a lower estimated glomerular filtration rate (eGFR), with a pooled OR of 1.84 (95% C.I.: 1.24–2.73) and 1.60 (95% C.I.: 1.19–2.16), respectively. A greater OSA severity was also found to be related to a higher OR, with a mild group OR of 1.45 (95% C.I.: 1.19–1.77) and a moderate and severe group OR of 2.39 (95% C.I.: 1.96–2.90).

CONCLUSIONS

Our study demonstrated that OSA is significantly associated with poorer renal function.

Obstructive sleep apnoea in diabetes: Does it matter?

Obstructive sleep apnoea (OSA) is very common in patients with Type 2 diabetes (T2D), which is not surprising considering that obesity is a common risk factor for both conditions. In general population studies, OSA has been shown to be associated with several comorbidities including increased risk of road traffic accidents, T2D, hypertension and lack of nocturnal dipping of blood pressure, hyperlipidaemia, increased inflammation, increased risk of cardiovascular disease and mortality, increased risk of atrial fibrillation, worse quality of life, and erectile dysfunction. However, the impact of OSA on diabetes-related vascular and metabolic outcomes remains unclear. Furthermore, the impact of continuous positive airway pressure (CPAP) treatment in patients with T2D is also unclear. This unclarity regarding the impact of OSA and CPAP in patients with T2D has possibly contributed to the lack of screening for OSA in patients with T2D in the UK despite the high prevalence of OSA in patients with T2D. In this commentary, I provide an overview about OSA with a particular focus on its role and impact in patients with T2D.

Diseases of the retina and the optic nerve associated with obstructive sleep apnea

Many associations between ocular disorders and obstructive sleep apnea (OSA) have been studied, such as nonarteritic anterior ischemic optic neuropathy, glaucoma, papilledema, retinal vein occlusion, eyelid hyperlaxity, lower-eyelid ectropion and recurrent corneal erosions. The objective of this review is to synthetize the possible vascular disorders of the retina and the optic nerve associated with sleep apnea patients and to discuss the underlying pathophysiological hypotheses. Main mechanisms involved in the ocular complications of OSA are related to intermittent hypoxia, sympathetic system activation, oxidant stress, and deleterious effects of endothelin 1. The main evidence-based medicine data suggest that OSA should be screened in patients with ischemic optic neuropathy and diabetic retinopathy. The effect of OSA treatment and emerging therapies are discussed.

Spare the rods and spoil the retina: revisited

Visual function improves with oxygen inhalation in people with diabetes even in the absence of visible retinopathy. Rods consume the most oxygen in the retina due to the high metabolic activity required to maintain the dark current. Therefore, Arden hypothesized that in diabetes where oxygen supply may also be affected due to the changes in retinal vasculature, prevention of dark adaptation may be a viable option to prevent or decrease the rate of progression of diabetic retinopathy. Animal experiments have proven that the absence of rods decreases the development of retinal neovascularisation. The same principle applies to panretinal photocoagulation, an established treatment for proliferative diabetic retinopathy. Recently, a few clinical studies have also shown that preventing dark adaptation by suppressing rods with 500-nm light source at night decreases the rate of progression of early diabetic retinopathy and maculopathy in the short-term. We await the results of a large two-year multi-centre trial (CLEOPATRA trial) to evaluate the long-term effects of decreasing dark adaptation by applying a 500nm light source as a mask over eyes with non-central diabetic macular oedema.

Hypoxia and Dark Adaptation in Diabetic Retinopathy: Interactions, Consequences, and Therapy

In diabetes, retinal blood flow is compromised, and retinal hypoxia is likely to be further intensified during periods of darkness. During dark adaptation, rod photoreceptors in the outer retina are maximally depolarized and continuously release large amounts of the neurotransmitter glutamate-an energetically demanding process that requires the highest oxygen consumption per unit volume of any tissue of the body. In complete darkness, even more oxygen is consumed by the outer retina, producing a steep fall in the retinal oxygen tension curve which reaches a nadir at the depth of the mitochondrial-rich rod inner segments. In contrast to the normal retina, the diabetic retina cannot meet the added metabolic load imposed by the dark-adapted rod photoreceptors; this exacerbates retinal hypoxia and stimulates the overproduction of vascular endothelial growth factor (VEGF). The use of nocturnal illumination to prevent dark adaptation, specifically reducing the rod photoreceptor dark current, should ameliorate diabetic retinopathy.

Sleep Optimization and Diabetes Control: A Review of the Literature

Pre-diabetes and diabetes occur secondary to a constellation of pathophysiological abnormalities that culminate in insulin resistance, which results in reduced cellular glucose uptake and increased glucose production. Although pre-diabetes and diabetes have a strong genetic basis, they are largely environmentally driven through lifestyle factors. Traditional lifestyle factors such as diet and physical activity do not fully explain the dramatic rise in the incidence and prevalence of diabetes mellitus. Sleep has emerged as an additional lifestyle behavior, important for metabolic health and energy homeostasis. In this article, we review the current evidence surrounding the sleep-diabetes association.