Sleep apnea and subsequent cancer incidence

Revealing the Causal Impact of Obstructive Sleep Apnea on Cancer Risk: Insights from Mendelian randomization analysis

BACKGROUND

Observational studies have suggested that obstructive sleep apnea (OSA) may have a potential carcinogenic role. However, the results of these studies were inconsistent and the underlying genetic mechanisms have yet to be fully understood.

METHODS

We conducted a Mendelian randomization (MR) analysis using large-scale genome-wide association studies summary statistics to explore the possible causal effect of OSA on the risk of 16 specific-site cancers in the European population.

RESULTS

The MR analysis revealed a significantly negative correlation between OSA and the susceptibility to prostate cancer (OR: 0.87, 95%CI 0.79-0.95, p = 0.002) and a causal increase in the vulnerability to pancreatic malignancies (OR: 2.02, 95%CI 1.1-3.7, p = 0.02). However, no causal effects of OSA on other specific-site cancers were found. Sensitivity analyses demonstrated no significant heterogeneity or horizontal pleiotropy, thus validating the robustness of the original results.

CONCLUSION

Our MR provided important insights into the causal associations between OSA and cancer risk, highlighting both protective and potentially harmful effects of OSA on different cancer types.

The Association of Obstructive Sleep Apnea with Urological Cancer Incidence and Mortality-A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

While obstructive sleep apnea (OSA) and urological cancer are both strongly associated with hypoxia, controversy exists regarding their association with each other. This study aims to summarize and synthesize evidence to clarify the association between OSA and urological cancer incidence and mortality.

METHODS

According to a prespecified protocol, PubMed, Embase, Cochrane Library, and Scopus were searched from inception to November 16, 2023, for observational and randomized studies reporting the association of OSA with urological cancer incidence or mortality. We pooled maximally covariate-adjusted hazard ratios (HRs) using a random-effects inverse variance-weighted model. Two reviewers independently assessed the quality of evidence using the Newcastle-Ottawa Scale and the Grading of Recommendations, Assessment, Development and Evaluation framework.

KEY FINDINGS AND LIMITATIONS

From 1814 records, we included 12 studies comprising 9 290 818 participants in total, of which nine studies were analyzed quantitatively. OSA patients had an increased risk of kidney (HR: 1.75, 95% confidence interval [CI]: 1.21-2.53) and bladder (HR: 1.76, 95% CI: 1.05-2.96) cancer. However, OSA was not associated with prostate cancer incidence (HR: 1.29, 95% CI: 0.82-2.04). We systematically reviewed evidence surrounding OSA and testicular cancer incidence and urological cancer mortality.

CONCLUSIONS AND CLINICAL IMPLICATIONS

OSA may be associated with a higher risk of kidney and bladder cancer, but not prostate cancer. Future work may help clarify the possibility of a dose-response relationship between OSA and urological cancer, and the effect of OSA treatment on urological cancer incidence or progression.

PATIENT SUMMARY

This research highlights a potential longitudinal association between OSA and kidney and bladder cancer, but not prostate cancer.

Association between obstructive sleep apnea and risk of lung cancer: findings from a collection of cohort studies and Mendelian randomization analysis

Background

Previous cohort studies conducted on large populations have suggested a potential association between obstructive sleep apnea (OSA) and an elevated risk of developing lung cancer. However, limited research has comprehensively investigated the correlation between the two conditions, and the causal effect remains unknown.

Methods

A comprehensive and systematic search was conducted across various databases, including PubMed, Web of Science, Cochrane Library, and Embase, from their inception dates to November 1, 2023. To assess the relationship between OSA and lung cancer, a meta-analysis was performed. Additionally, a two-sample Mendelian randomization (MR) study was conducted using summary data. The datasets included 336,659 individuals from the FinnGen study for OSA and 27,209 individuals from the International Lung Cancer Consortium study, as well as 420,473 individuals from the UK Biobank study for lung cancer. The estimates from each study were aggregated using the inverse variance-weighted method.

Results

Data from six population-based cohort studies, encompassing 6,589,725 individuals, indicated a significant increase in the risk of developing lung cancer among patients with OSA (HR 1.28, 95% CI 1.07-1.54). However, the MR analysis did not support a causal relationship between OSA and lung cancer (OR 1.001, 95% CI 0.929-1.100). This lack of association was consistent across specific subtypes of lung cancer, including non-small-cell lung cancer (OR 1.000, 95% CI 0.999-1.000, p = 0.974), lung adenocarcinoma (OR 0.996, 95% CI 0.906-1.094, p = 0.927), and squamous cell lung carcinoma (OR 1.034, 95% CI 0.937-1.140, p = 0.507).

Conclusions

Our meta-analysis findings suggest an elevated risk of lung cancer among individuals with OSA. However, the MR analysis did not provide evidence supporting a causal relationship between OSA and lung cancer. Further investigation is required to uncover the underlying factors contributing to the observed association between OSA and lung cancer risk.

Cancer Prevention Among Firefighters: Examining Lifestyle, Screening Behavior, and Beliefs

BACKGROUND

Firefighters are at increased risk of developing cancer due to occupational exposures, but they may also face increased risk due to their lifestyle, such as the quality of their diet and physical activity. Cancer beliefs and screening behavior could also influence their cancer risk. The current study aimed to identify individual differences associated with lifestyle behaviors, cancer screening, and cancer beliefs among firefighters; to describe the strategies firefighters use to adapt to their work schedule; and to describe topics firefighters believe are the most important to address in their workplace.

METHODS

Career firefighters (N = 171) in a medium-sized U.S. city completed an online survey.

FINDINGS

Logistic regression analyses identified age, education, racial identity, years of fire service, perceived stress, and rank as predictors of responses to items addressing cancer screening, lifestyle behaviors, and cancer beliefs. Although results varied, age, education, and racial identity were associated with most of the outcomes. Strategies related to sleep such as getting the right amount and napping, exercise, and getting family/roommate support were selected as the top adaptive strategies for work. Sleep, mental health/well-being, and work-life balance were selected most often as the most important topics to address in the fire service, with topics related to reducing occupational exposures receiving less attention.

CONCLUSIONS/APPLICATION TO PRACTICE

The findings suggest individual differences, such as age, education, and racial identity, should be considered when developing occupational health interventions for firefighters. Interventions related to mental health, work-life balance, and sleep may be desired most by those in the fire service.

Association of obstructive sleep apnea with risk of lung cancer: a nationwide cohort study in Korea

Current knowledge regarding the relationship between obstructive sleep apnea (OSA) and the risk of lung cancer is limited. This study aimed to evaluate associations between OSA and the incidence of lung cancer based on the Korean National Health Information Database. The study outcome was the incidence of newly diagnosed lung cancer, and a Cox proportional hazards model was used for analysis. A total of 181,070 adult patients newly diagnosed with OSA between 2011 and 2018 were matched with those without OSA by up to 1:5 propensity score matching based on age and sex. During follow-up over (mean ± standard deviation) 9.1 ± 2.0 years, 2614 incident cases of lung cancer were identified. The incidence rate was 39.51 per 100,000 person-years in the OSA group, and 24.93 per 100,000 person-years in the control group. After adjusting for income and the presence of comorbidities, the association remained significant (hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.74-2.18, p-value < 0.001). The adjusted HR for incident lung cancer was 2.14 (95% CI 1.69-2.70) in female patients with OSA, and 1.90 (95% CI 1.67-2.16) in male patients with OSA. The risk of incident lung cancer increased with age, with a HR of 2.99 (95% CI 2.46-3.64) in those aged ≥ 65 years. This nationwide study showed an independent association between OSA and an increased risk of lung cancer in the Korean population.

A review of obstructive sleep apnea and lung cancer: epidemiology, pathogenesis, and therapeutic options

Despite undeniable advances in modern medicine, lung cancer still has high morbidity and mortality rates. Lung cancer is preventable and treatable, and it is important to identify new risk factors for lung cancer, especially those that can be treated or reversed. Obstructive sleep apnea (OSA) is a very common sleep-breathing disorder that is grossly underestimated in clinical practice. It can cause, exacerbate, and worsen adverse outcomes, including death and various diseases, but its relationship with lung cancer is unclear. A possible causal relationship between OSA and the onset and progression of lung cancer has been established biologically. The pathophysiological processes associated with OSA, such as sleep fragmentation, intermittent hypoxia, and increased sympathetic nervous excitation, may affect normal neuroendocrine regulation, impair immune function (especially innate and cellular immunity), and ultimately contribute to the occurrence of lung cancer, accelerate progression, and induce treatment resistance. OSA may be a contributor to but a preventable cause of the progression of lung cancer. However, whether this effect exists independently of other risk factors is unclear. Therefore, by reviewing the literature on the epidemiology, pathogenesis, and treatment of lung cancer and OSA, we hope to understand the relationships between the two and promote the interdisciplinary exchange of ideas between basic medicine, clinical medicine, respiratory medicine, sleep medicine, and oncology.

Sleep disorders and cancer incidence: examining duration and severity of diagnosis among veterans

Introduction

Sleep disruption affects biological processes that facilitate carcinogenesis. This retrospective cohort study used de-identified data from the Veterans Administration (VA) electronic medical record system to test the hypothesis that patients with diagnosed sleep disorders had an increased risk of prostate, breast, colorectal, or other cancers (1999-2010, N=663,869). This study builds upon existing evidence by examining whether patients with more severe or longer-duration diagnoses were at a greater risk of these cancers relative to those with a less severe or shorter duration sleep disorder.

Methods

Incident cancer cases were identified in the VA Tumor Registry and sleep disorders were defined by International Classification of Sleep Disorder codes. Analyses were performed using extended Cox regression with sleep disorder diagnosis as a time-varying covariate.

Results

Sleep disorders were present among 56,055 eligible patients (8% of the study population); sleep apnea (46%) and insomnia (40%) were the most common diagnoses. There were 18,181 cancer diagnoses (41% prostate, 12% colorectal, 1% female breast, 46% other). The hazard ratio (HR) for a cancer diagnosis was 1.45 (95% confidence interval [CI]: 1.37, 1.54) among those with any sleep disorder, after adjustment for age, sex, state of residence, and marital status. Risks increased with increasing sleep disorder duration (short [<1-2 years] HR: 1.04 [CI: 1.03-1.06], medium [>2-5 years] 1.23 [1.16-1.32]; long [>5-12 years] 1.52 [1.34-1.73]). Risks also increased with increasing sleep disorder severity using cumulative sleep disorder treatments as a surrogate exposure; African Americans with more severe disorders had greater risks relative to those with fewer treatments and other race groups. Results among patients with only sleep apnea, insomnia, or another sleep disorder were similar to those for all sleep disorders combined.

Discussion

The findings are consistent with other studies indicating that sleep disruption is a cancer risk factor. Optimal sleep and appropriate sleep disorder management are modifiable risk factors that may facilitate cancer prevention.

Preconception sleep duration, non-daytime work schedules, and incidence of spontaneous abortion: a prospective cohort study

STUDY QUESTION

To what extent do self-reported sleep duration and non-daytime work schedules in either partner affect the rate of spontaneous abortion (SAB)?

SUMMARY ANSWER

Incidence of SAB had little association with female sleep duration and a modest positive association with male short sleep duration, female work at night, and discrepant work schedules among partners.

WHAT IS KNOWN ALREADY

Several studies have reported an association between short sleep duration in either partner and reproductive health outcomes, including fecundability. Moreover, certain types of female occupational exposures during pregnancy have been associated with an increased risk of SAB. No studies have evaluated SAB risk in relation to male sleep and work schedules, or joint exposures within a couple.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study included 9357 female participants and 2602 of their male partners residing in North America (June 2013 to April 2023).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants enrolled when they were attempting pregnancy and completed self-administered baseline questionnaires about their average sleep duration and work schedules. Among those who conceived, we ascertained SAB and gestational age at loss via follow-up questionnaires. We used multivariable Cox proportional hazards models with gestational weeks as the time scale to estimate hazard ratios (HRs) and 95% CIs relating SAB with sleep duration and non-daytime work schedules for female and male participants, and the couple. We used inverse probability weighting to account for potential selection bias due to the possibility of differential participation of male partners with respect to the exposures.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to female participants with recommended sleep (7-8.9 h), those reporting short sleep duration (<6 h) did not have a higher rate of SAB (HR 0.88, 95% CI 0.69, 1.13). Short self-reported sleep duration among male participants was modestly associated with a higher rate of SAB (adjusted and weighted HR 1.30, 95% CI 0.96, 1.75). Female night work at night (adjusted HR 1.19, 95% CI 1.02, 1.38) and male non-daytime work (adjusted and weighted HR 1.26, 95% CI 1.00, 1.59) were associated with modestly higher rates of SAB, whereas female rotating shift work was not (adjusted HR 0.91, 0.78, 1.05) compared with daytime workers. Couples in which work schedules were discrepant had an elevated rate of SAB if the male partner worked a non-daytime shift (adjusted and weighted HR 1.46, 95% CI 1.13, 1.88) compared with couples in which both members worked during the day. The corresponding HR if only the female partner worked a non-daytime shift was 1.21 (95% CI 0.92, 1.58).

LIMITATIONS, REASONS FOR CAUTION

Data on sleep duration and work schedules were based on self-report, which is vulnerable to misclassification, particularly since participants were asked to report their average sleep duration during the past month. Work exposures were heterogeneous, as many different types of employment may require night and shift work and may have different associations with SAB.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings are consistent with previous research indicating that some types of female employment schedules may be associated with SAB incidence. This is the first study to indicate a relationship between SAB and male employment schedules, indicating that discrepant work schedules within a couple might be relevant.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development grants R01HD105863 (PIs: L.A.W. and M.L.E.), R01HD086742 (PIs: L.A.W. and E.E.H.), and R21HD072326 (PI: L.A.W.). PRESTO has received in-kind donations from Swiss Precision Diagnostics and Kindara.com for primary data collection. L.A.W. is a consultant for AbbVie, Inc. and the Gates Foundation. M.L.E. is an advisor for and holds stock in Ro, Hannah, Dadi, Underdog, Vseat, & Doveras. The other authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Analyzing Cancer Incidence Trends in Oman From 1996 to 2019: A Comprehensive Study of the National Cancer Annual Reports

PURPOSE

Previous studies have reported that cancer incidence trends in Oman varied by tumor site and sex. No comprehensive analysis of all cancer sites had been reported. The objective of this study is to analyze cancer incidence trends in Oman and calculate the annual percent change (APC) in age-standardized rates (ASRs) for all-cancer and 61 individual cancer sites in Omani men and women from 1996 to 2019.

METHODS

We gathered incidence data from The Omani National Cancer Registry for all cancers combined and individual tumor sites. We estimated the APC using Poisson regression.

RESULTS

The cancer ASR in the Omani population increased by 23% (from 95/100,000 in 1996 to 117.2/100,000 in 2019), with the increase being more pronounced in females (48% v 7% in males). Among the male population, there was significant increase in the ASRs of colon, rectum, thyroid, and prostate cancers, with APCs of 6.92%, 4.24%, 4.19%, and 2.03%, respectively. Among females, all-cancer incidence showed significant increase (APC = 1.39%), and increasing trends were observed in uterine, colon, rectum, thyroid, and breast cancers (APCs = 7.57%, 7.08%, 5.19%, 5.16%, and 4.19%, respectively).

CONCLUSION

The ASR of all-cancer increased significantly in Omani women but not in men. Uterine cancer had the highest APC. Colorectal cancer and thyroid ASR increased in both males and females. Breast and prostate cancers showed increasing trends. Further research is needed to explore factors contributing to increasing cancer incidences.

Obstructive Sleep Apnea and Colorectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Obstructive sleep apnea (OSA), characterised by recurrent episodes of upper airway collapse, intermittent hypoxia (IH) and sleep fragmentation (SF), has been associated with carcinogenesis in pre-clinical models. The relationship between OSA and colorectal cancer (CRC) in clinical studies is controversial.

AIM

The objective of this meta-analysis was to assess the association between OSA and CRC.

METHODS

Two independent investigators searched studies indexed in CINAHL, MEDLINE, EMBASE, the Cochrane Database and clinicaltrials.gov that were randomised controlled trials (RCT) or observational studies evaluating the relationship between OSA and CRC. Studies were included if they had available odds ratios (OR) and relative risks (RR) or if hazard ratios (HR) with 95% confidence intervals (CI) were available and a reference group composed of participants who did not have OSA. OR and 95% CI were calculated using a random-effect, generic inverse variance method.

RESULTS

We included four observational studies out of 85 records, comprising a combined cohort of 5,651,662 identified patients in the data analysis. Three studies used polysomnography to identify OSA. The pooled OR of CRC in patients with OSA was 1.49 (95% CI, 0.75 to 2.97). The statistical heterogeneity was high with I2 of 95%.

CONCLUSIONS

Our study is unable to conclusively point towards OSA being a risk factor in the development of CRC, despite the plausible biological mechanisms for this. Further well-designed prospective RCT assessing the risk of CRC in patients with OSA and the impact of OSA treatments on the incidence and prognosis of CRC are needed.

The Impact of Immunotherapy on Sleep and Circadian Rhythms in Patients with Cancer

Immunotherapy has revolutionized treatments for both early and advanced cancers, and as their role evolves, their impact on sleep and circadian rhythms continues to unfold. The recognition, evaluation, and treatment of sleep and circadian rhythm disturbance leads to improved symptom management, quality of life and treatment outcomes. An intricate complex relationship exists in the microenvironment with immunity, sleep and the tumor, and these may further vary based on the cancer, addition of standard chemotherapy, and pre-existing patient factors. Sleep and circadian rhythms may offer tools to better utilize immunotherapy in the care of cancer patients, leading to better treatment outcome, reduced symptom burden, and increased quality of life.

Does OSA Increase Risk for Cancer?: A Large Historical Sleep Clinic Cohort Study

BACKGROUND

The relationship between OSA and cancer is unclear.

RESEARCH QUESTION

What is the association between OSA and cancer prevalence and incidence in a large Western Australian sleep clinic cohort (N = 20,289)?

STUDY DESIGN AND METHODS

OSA severity was defined by apnea-hypopnea index (AHI) and nocturnal hypoxemia (duration and percentage at oxygen saturation < 90%) measured by in-laboratory polysomnogram. Measures of potential confounding included age, sex, BMI, smoking status, socioeconomic status, and BP. Outcomes were determined from the Western Australian cancer and death registries. Analyses were confined within periods using consistent AHI scoring criteria: January 1, 1989, to July 31, 2002 (American Sleep Disorders Association criteria), and August 1, 2002, to June 30, 2013 (Chicago criteria). We examined associations of AHI and nocturnal hypoxemia with cancer prevalence using logistic regression and cancer incidence using Cox regression analyses.

RESULTS

Cancer prevalence at baseline was 329 of 10,561 in the American Sleep Disorders Association period and 633 of 9,728 in the Chicago period. Nocturnal hypoxemia but not AHI was independently associated with prevalent cancer following adjustment for participant age, sex, BMI, smoking status, socioeconomic status, and BP. Of those without prevalent cancer, cancer was diagnosed in 1,950 of 10,232 (American Sleep Disorders Association) and 623 of 9,095 (Chicago) participants over a median follow-up of 11.2 years. Compared with the reference category (no OSA, AHI < 5 events per hour), univariable models estimated higher hazard ratios for cancer incidence for mild (AHI 5-15 events per hour), moderate (AHI 15.1-30 events per hour), and severe (AHI > 30 events per hour) OSA. Multivariable analyses consistently revealed associations between age and, in some cases, sex, BMI, and smoking status, with cancer incidence. After adjusting for confounders, multivariable models showed no independent association between OSA severity and increased cancer incidence.

INTERPRETATION

Nocturnal hypoxemia is independently associated with prevalent cancer. OSA severity is associated with incident cancer, although this association seems secondary to other risk factors for cancer development. OSA is not an independent risk factor for cancer incidence.

Self-reported sleep disorders and the risk of all cancer types: evidence from the Kailuan Cohort study

OBJECTIVES

Previous studies that focussed on sleep disturbance have primarily examined specific aspects of sleep disorders rather than considering overall sleep quality. We aimed to investigate different sleep disorders and their combination as risk factors for different types of cancer.

STUDY DESIGN

Prospective cohort study.

METHODS

In this prospective cohort study, we included 78,232 participants. A self-reported questionnaire was used to address insomnia, daytime sleepiness, snoring, and sleep duration. Overall sleep quality was evaluated by summarising these four sleep parameters. Cox proportional hazards analysis was used to estimate the hazard ratios and their 95% confidence intervals for determining the effect of the overall sleep-quality score and its components on the risk of incident cancer.

RESULTS

During a median follow-up of 5.67 years, 1266 participants were diagnosed with incident cancer. Compared to participants in the best sleep-quality score group, participants in the worst sleep-quality score group had a higher subsequent risk of overall cancer, and colorectal, breast, uterine or uterine cervical, prostatic, kidney, and bladder cancer. Participants with insomnia and snoring status had an elevated risk of head and neck, breast, uterine or uterine cervical, prostatic, kidney, bladder cancer, and lymphoma.

CONCLUSIONS

Poor overall sleep-quality scores as well as poor scores for the scale's components, including insomnia and snoring status, elevated the risk of overall and several specific-site cancers.

TRIAL REGISTRATION

Kailuan Study, ChiCTR2000029767. Registered 12 February, 2020-Retrospectively registered, https://www.chictr.org.cn/showprojEN.html?proj=48316.

Are sleep disorders associated with the risk of gastrointestinal cancer?-A case-control study

PURPOSE

Sleep disorders are among the most common health problems worldwide and are linked to a variety of physical and mental health problems. Recently, there has been increasing evidence of an association between sleep disorders and cancer risk. We aimed to investigate this association specifically for cancers of the gastrointestinal (GI) tract.

METHODS

Using the DA database (IQVIA), adult patients diagnosed with GI cancer between January 2010 and December 2022 were retrospectively compared to a 1:1 propensity score-matched cohort of patients without cancer. The outcome of the study was the association between sleep disorders and subsequent diagnosis of GI cancer. To determine whether sleep disorders were more common in patients with GI cancer than in patients without GI cancer, logistic regression models were used to estimate odds ratios (ORs) with 95% confidence intervals (95% CI).

RESULTS

After matching, 37,161 cases with GI cancer and 37,161 controls without cancer were available for analysis. No association with cancer was found for sleep disorders in the overall history before the index date (OR 1.04; 95% CI 0.96-1.12), but considering sleep disorders documented within 1 year before the index date showed a positive association with GI cancer overall (OR 1.20; 95% CI 1.08-1.34). Stratified analyses by cancer site revealed higher odds of sleep disorders prior to diagnosis of gastric, pancreatic, and colorectal cancer.

CONCLUSION

Our findings suggest that sleep disorders might be indicative of short-term health outcomes, including GI cancer, suggesting a role for sleep disorder screening in the context of cancer prevention efforts.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

The Burden of Comorbidities in Obstructive Sleep Apnea and the Pathophysiologic Mechanisms and Effects of CPAP

Micro-arousals and the repeated desaturation of oxyhemoglobin, which are typical in obstructive sleep apnea syndrome (OSAS), have adverse effects on the health of patients, leading to a wide range of complications such as cardiovascular (arterial hypertension, pulmonary hypertension, chronic heart failure, arrhythmias, myocardial infarction), cerebrovascular (strokes), metabolic (insulin resistance, obesity, diabetes mellitus, metabolic syndrome), gastrointestinal (non-alcoholic liver disease), urinary (chronic renal failure), and neuropsychiatric complications as well as a wide range of malignancies. These, in turn, have multilateral effects on familial, occupational, and social life, as well as increasing the risks of road traffic accidents and accidents at the workplace. Awareness, timely screening, and the prevention of complications play important roles in diagnosing and treating comorbid conditions. This review focuses on comorbidities in OSAS and the effect of Continuous Positive Airway Pressure (CPAP) therapy on their prognoses.

Sleep disturbance and gastrointestinal cancer risk: a literature review

Sleep, accounting for roughly one-third of a person's life, plays an important role in human health. Despite the close association between sleep patterns and medical diseases proven by several studies, it has been neglected in recent years. Presently, all societies are facing the most challenging health-threatening disease, cancer. Among all cancer types, gastrointestinal (GI) cancers, especially colorectal type, seem to be one of the most relevant to an individual's lifestyle; thus, they can be prevented by modifying behaviors most of the time. Previous studies have shown that disruption of the 24-h sleep-wake cycle increases the chance of colorectal cancer, which can be due to exposure to artificial light at night and some complex genetic and hormone-mediated mechanisms. There has also been some evidence showing the possible associations between other aspects of sleep such as sleep duration or some sleep disorders and GI cancer risk. This review brings some information together and presents a detailed discussion of the possible role of sleep patterns in GI malignancy initiation.

Obstructive sleep apnea and the incidence and mortality of gastrointestinal cancers: a systematic review and meta-analysis of 5,120,837 participants

Background

Emerging evidence has shown higher overall cancer incidence in patients with obstructive sleep apnea. Gastrointestinal cancers, including esophageal, stomach, liver, pancreas, and colorectal cancers account for 26% of incident cancers. However, the link between gastrointestinal cancers and obstructive sleep apnea is still unclear. We performed a systematic review and meta-analysis (registered PROSPERO CRD42021220836) to investigate the association between obstructive sleep apnea and incidence of gastrointestinal cancer.

Methods

We searched four electronic databases (PubMed, Embase, Cochrane Library, Scopus) and included studies published from inception till 15th November 2020 reporting the association of obstructive sleep apnea with gastrointestinal cancer incidence. Extracted data was meta-analyzed in a random-effects model.

Results

A total of seven studies were included, forming a combined cohort of 5,120,837 patients. Studies which adjusted for demographics and comorbidities were included in meta-analysis. Among four studies with 7-11 years of median follow-up, patients with obstructive sleep apnea experienced increased incidence of colorectal cancer (HR 1.70, 95% CI: 1.48-1.96, I²=22%). Pancreatic cancer incidence was nominally increased in three studies (HR 1.36, 95% CI: 0.88-2.09, I²=96), though this was not statistically significant. There was no association between obstructive sleep apnea and liver cancer incidence among three studies (HR 0.99, 95% CI: 0.81-1.22, I²=84). However, the lack of a statistically significant relationship between obstructive sleep apnea and pancreatic cancer in our meta-analysis does not necessarily imply the true absence of an association.

Conclusions

An increased risk of colorectal cancer was seen in patients with obstructive sleep apnea among studies with long-term follow-up. Further research is required to explore the utility of incorporating obstructive sleep apnea screening into colorectal cancer screening guidelines to identify high-risk individuals and to confirm a possible association of obstructive sleep apnea with pancreatic cancer.

PROSPERO Registration

CRD42021220836.

Association of obstructive sleep apnea and nocturnal hypoxemia with all-cancer incidence and mortality: a systematic review and meta-analysis

STUDY OBJECTIVES

Biological models suggest that obstructive sleep apnea (OSA) is potentially carcinogenic. We aimed to clarify the inconsistent epidemiological literature by considering various traditional and novel OSA severity indices.

METHODS

We systematically searched PubMed, Embase, Scopus, and the Cochrane Library for observational or randomized studies of associations of OSA, measured by diagnostic codes or any index, each with all-cancer incidence or mortality in adults, compared with participants with no/mild OSA. Two reviewers independently selected studies, extracted data, and evaluated study bias using the Newcastle-Ottawa scale and quality of evidence using GRADE (Grading of Recommendations Assessment, Development, and Evaluation). We performed inverse variance-weighted, random-effects meta-analyses and sensitivity analyses.

RESULTS

We included 20 observational studies (5,340,965 participants), all with moderate/low bias, from 1,698 records. Based on T90 (sleep duration with oxygen saturation < 90%), patients with OSA who had moderate (T90 > 1.2%, hazard ratio [HR] = 1.28, 95% confidence interval [CI] = 1.07-1.54) and severe nocturnal hypoxemia (T90 > 12%, HR = 1.43, 95% CI = 1.16-1.76) experienced 30%-40% higher pooled all-cancer risk than normoxemic patients, after multiple adjustment for covariates including obesity. Furthermore, severe nocturnal hypoxemia nearly tripled all-cancer mortality (HR = 2.66, 95% CI = 1.21-5.85). Patients with apnea-hypopnea index-defined severe OSA, but not moderate OSA, had higher all-cancer risk (HR = 1.18, 95% CI = 1.03-1.35) but similar all-cancer mortality as patients without OSA. An OSA diagnosis was not associated with all-cancer risk. Evidence quality ranged from low to moderate. Insufficient evidence was available on the oxygen desaturation index, lowest/median saturation, and arousal index.

CONCLUSIONS

In patients with OSA, nocturnal hypoxemia is independently associated with all-cancer risk and mortality. Future studies should explore if risk differs by cancer type, and whether cancer screening and OSA treatment are beneficial.

SYSTEMATIC REVIEW REGISTRATION

Registry: PROSPERO; URL: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=220836; Identifier: CRD42021220836.

CITATION

Tan BKJ, Teo YH, Tan NKW, et al. Association of obstructive sleep apnea and nocturnal hypoxemia with all-cancer incidence and mortality: a systematic review and meta-analysis. J Clin Sleep Med. 2022;18(5):1427-1440.

The Incidence of Cancer Is Increased in Hospitalized Adult Patients With Obstructive Sleep Apnea in China: A Retrospective Cohort Study

Background

The association between obstructive sleep apnea (OSA) and the incidence and mortality of cancer remain unclear, especially in Asian populations. Thus, this study was conducted to explore the relationship between OSA and the incidence and mortality of cancer in hospitalized patients.

Methods

This retrospective cohort study evaluated inpatients from Guangdong Provincial People’s Hospital for suspected OSA between January 2005 and December 2015. Cancer incidence, all-cause mortality, and cancer mortality and were determined using data from the hospital information system and Centers for Disease Control. Between-group comparisons were carried out by performing a chi-square test and analysis of variance. Kaplan–Meier analysis and the Cox proportional risk model were applied to investigate the association between OSA and cancer incidence and mortality.

Results

Of the 4,623 hospitalized patients included, 3,786 (81.9%) patients were diagnosed with OSA. After a median follow-up of 9.1 years (interquartile range, 9.79–11.44), the incidence of cancer was 6.6% (251/3,786), with lung cancer having the highest incidence at 1.6% (60/3,786). The mortality rate of OSA patients was higher than that of non-OSA patients (16.83% vs.12.78%, p=0.008), but the relationship between apnea-hypopnea index (AHI), oxygen saturation less than 90% (TSat90), and cancer mortality was not statistically significant (p>0.05).The mortality rate for all types of cancer was 2.8% (105/3,786), with lung cancer having the highest mortality rate at 0.8% (32/3,786). The cumulative incidence of cancer in the severe OSA group was 8.2%, which was higher than that in the normal, mild, and moderate OSA groups (P=0.010). Further, the Cox proportional risk regression model showed a progressive enhancement in the risk of cancer incidence as the AHI increased (adjusted hazard ratio [HR]: 1.009 [95% confidence interval (CI): 1.003–1.016], P=0.005). Based on subgroup analysis, the risk of cancer increased as the AHI increased in patients aged <65 years (adjusted HR: 1.019 [95% CI: 1.007–1.031], P=0.002). In addition, the cancer incidence was significantly higher in the severe OSA group than in the normal, mild, and moderate OSA groups (adjusted HR: 2.825 [95% CI: 1.358–5.878], P=0.019).

Conclusion

The incidence of cancer is higher in patients with OSA than in non-OSA patients and is significantly positively associated with the severity of OSA. Particularly, for OSA patients aged <65 years, lung cancer is the main cause of death in those with new-onset cancer. Mortality was higher in OSA patients than in non-OSA patients.

The Association of Obstructive Sleep Apnea With Breast Cancer Incidence and Mortality: A Systematic Review and Meta-analysis

Purpose

Emerging evidence from animal models suggests that intermittent hypoxia due to obstructive sleep apnea (OSA) is a risk factor for breast cancer. Despite their biological plausibility, human epidemiological studies have reported conflicting results. Therefore, we conducted a meta-analysis to delineate this relationship.

Methods

We searched the PubMed, Embase, Scopus, and Cochrane Library databases for eligible studies from inception until June 6, 2021. Two reviewers selected randomized trials or observational studies reporting the association between OSA and breast cancer incidence compared with those without OSA. Two reviewers extracted relevant data and assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework and Newcastle-Ottawa Scale (NOS). We pooled the maximally covariate-adjusted hazard ratios (HRs) using a random-effects inverse variance-weighted meta-analysis and performed pre-specified subgroup analyses.

Results

We included six studies out of 1,707 records, comprising a combined cohort of 5,165,200 patients. All studies used the International Classification of Diseases codes to classify OSA and breast cancer. OSA patients had a 36% increased breast cancer risk (HR, 1.36; 95% confidence interval [CI], 1.03–1.80; N = 6, I² = 96%) compared to those without OSA. Most studies adjusted for confounders, such as age, sex, obesity, diabetes mellitus, alcohol use, and hypertension. Subgroup analyses for studies with (1) multivariate adjustment and (2) at least five years of follow-up yielded HRs of 1.35 (95% CI, 0.98–1.87; N = 5, I² = 96%) and 1.57 (95% CI, 1.14–2.18; N = 4; I² = 90%), respectively. One Mendelian randomization study suggested a causal relationship, with a two-fold increase in the odds of breast cancer in patients with OSA.

Conclusion

This meta-analysis suggested that OSA is a risk factor for breast cancer. Future studies should explore the dose-response relationship between OSA and breast cancer, and whether treatment may mitigate breast cancer risk or progression.

The association of obstructive sleep apnea with melanoma incidence and mortality: a meta-analysis of 5,276,451 patients

BACKGROUND

Melanoma is the most aggressive and lethal form of skin cancer. While emerging in-vivo evidence suggests that intermittent hypoxia, a hallmark feature of obstructive sleep apnea (OSA), may induce melanoma tumorigenesis, the epidemiological association between OSA and melanoma has been inconsistent.

METHODS

We performed a literature search of PubMed, Embase, Scopus and Cochrane Library from inception until 6 June 2021. Two reviewers independently selected randomized trials or observational studies that reported the association of OSA with melanoma incidence or mortality in adults, in comparison to participants with no OSA. Two reviewers independently extracted relevant data and assessed the quality of evidence using the GRADE framework and the Newcastle-Ottawa Scale (NOS). We pooled data using an inverse variance-weighted meta-analysis and ran pre-specified subgrourp analyses.

RESULTS

The meta-analysis included six studies out of 1897 records, comprising a combined cohort of 5,276,451 patients. All studies were adjusted for covariates, with majority of studies adjusting for age (N=5) and sex (N = 4). Compared to those without OSA, patients with OSA had 71% higher pooled hazards of melanoma (HR = 1.71; 95% CI: 1.08-2.69, I² = 99%). Subgroup analyses for studies with (1) median follow-up duration of at least five years, (2) prospective study design, (3) adjustment for obesity yielded HRs of 1.88 (95%CI:1.32-2.67, N = 5), 1.11 (95%CI:0.77-1.60, N = 2) and 1.52 (95%CI:0.75-3.08, N = 3) respectively. One study investigating the relationship between OSA and melanoma mortality detected no association. There were insufficient studies to assess publication bias.

CONCLUSIONS

Meta-analysis of mainly retrospective observational studies, with significant heterogeneity, suggests increased melanoma incidence in OSA patients. Future studies should prospectively explore the differential risk of melanoma for varying OSA severity, and whether timely OSA treatment may mitigate this risk.

Obstructive Sleep Apnea and Lung Cancer: A Systematic Review and Meta-analysis of 4,885,518 Participants

RATIONALE

In 2020, lung cancer was the leading cause of cancer deaths, and was the most common cancer in men. Though obstructive sleep apnea (OSA) has been postulated to be carcinogenic, epidemiological studies are inconclusive.

OBJECTIVES

We conducted this systematic review and meta-analysis to investigate the associations between OSA and the incidence and mortality of lung cancer.

METHODS

Four electronic databases (PubMed, Embase, Cochrane Library, and Scopus) were searched from inception till 6 June 2021 for randomized controlled trials and observational studies examining the association between sleep apnea and incident lung cancer. Two reviewers selected studies, extracted data, graded the risk of bias using the Newcastle-Ottawa scale and the quality of evidence using GRADE. Random-effects models were used to meta-analyze the maximally covariate-adjusted associations.

RESULTS

Seven studies were included in our systematic review; among which four were suitable for meta-analysis, comprising a combined cohort of 4,885,518 patients. Risk of bias was low to moderate. OSA was associated with a higher incidence of lung cancer (HR 1.25, 95%CI 1.02 to 1.53), with substantial heterogeneity (I²=97%). Heterogeneity was eliminated, with a stable pooled effect size, when including the three studies with at least 5 years of median follow-up (HR 1.32, 95%CI 1.27 to 1.37, I²=0%).

CONCLUSIONS

In this meta-analysis of 4,885,518 patients from four observational studies, patients with OSA had approximately 30% higher risk of lung cancer, compared to those without OSA. We suggest more clinical studies with longer follow-up as well as biological models of lung cancer be performed to further elucidate this relationship.

Sleep-disordered breathing and risk of the breast cancer: A meta-analysis of cohort studies

BACKGROUND

Sleep-disordered breathing (SDB) has been related to a higher risk of breast cancer whereas the results of previous studies are inconsistent. We, therefore, performed a meta-analysis to evaluate the association between SDB and subsequent risk of breast cancer in women.

METHODS

Cohort studies that investigated the temporal relationship between SDB and breast cancer incidence were obtained via search of PubMed, Embase and Web of Science from inception to 30 January 2021. Only studies with multivariate analyses were included. A fixed or a randomised effect model was applied according to the heterogeneity.

RESULTS

Eight cohort studies with 1 398 113 women were included. Pooled results with a randomised-effect model showed that compared with women without SDB at baseline, women with SDB had a significantly increased risk of breast cancer (risk ratio [RR]: 1.36, 95% confidence interval [CI]: 1.08 to 1.71, P = .01) with significant heterogeneity (P for Cochrane's Q test < .001, I²  = 95%). Subgroup analyses showed that SDB seemed to confer a more remarkably increased risk of breast cancer in elderly women (RR: 3.00, 95% CI: 1.33 to 6.76, P = .008) than that in non-elderly women (RR: 1.15, 95% CI: 1.02 to 1.29, P = .02; P for subgroup difference = .04). However, the association was not significantly affected by country of the study, study design, diagnostic strategy for SDB or adjustment of obesity (P for subgroup analyses all > .05).

CONCLUSIONS

SDB may be an independent risk factor for breast cancer in women, particularly in elderly females.

Intergenic SNPs in Obstructive Sleep Apnea Syndrome: Revealing Metabolic, Oxidative Stress and Immune-Related Pathways

There is strong evidence supporting the contribution of genetic factors to obstructive sleep apnea syndrome (OSAHS) susceptibility. In the current study we analyzed both in a clinical cohort and in silico, four single nucleotide polymorphisms SNPs, rs999944, rs75108997, rs35329661 and rs116133558 that have been associated with OSAHS. In 102 patients with OSAHS and 50 healthy volunteers, genetic testing of the above polymorphisms was performed. Polymorphism rs116133558 was invariant in our study population, whereas polymorphism rs35329661 was more than 95% invariant. Polymorphism rs999944 displayed significant (>5%) variance in our study population and was used in the binary logistic regression model. In silico analyses of the mechanism by which these three SNPs may affect the pathophysiology of OSAHS revealed a transcriptomic network of 274 genes. This network was involved in multiple cancer-associated gene signatures, as well as the adipogenesis pathway. This study, uncover a regulatory network in OSAHS using transcriptional targets of intergenic SNPs, and map their contributions in the pathophysiology of the syndrome on the interplay between adipocytokine signaling and cancer-related transcriptional dysregulation.

Obstructive sleep apnoea after radiotherapy for head and neck cancer

Objective

The aim of this study is to focus attention on obstructive sleep apnoea hypopnoea syndrome (OSHAS) as a sequela of non-surgical treatments of selected head and neck cancer (HNca), sharing our experience in drug-induced sleep endoscopy (DISE). To the best of our knowledge, this is the first study that documents dynamic anatomical and functional alterations during sleep in irradiated OSAHS patients by DISE.

Methods

A retrospective study of patients affected by OSAHS referring to our department from January 2018 to December 2019 was carried out. Inclusion criteria were: patients who underwent radiation or chemo-radiation for HNca affecting upper airways that presented sleep-related breathing disorders after treatment.

Results

6 patients with moderate to severe OSAHS and a clinical story of previous non-surgical treatment for an HNca were enrolled. DISE showed in all patients typical anatomical alterations observed in irradiated individuals. Four patients were treated with continuous positive airway pressure, while 2 subjects were treated with tailored minimal invasive surgery without post-operative complications.

Conclusions

Our results suggest that minimal invasive surgical treatments can be a good therapeutic option in very selected patients with post-irradiation iatrogenic OSAHS.

Obstructive sleep apnea and incidence of malignant tumors: a meta-analysis

OBJECTIVES

This paper assessed the connection between obstructive sleep apnea (OSA) and the incidence of malignant tumors.

METHODS

PubMed, Cochrane, Scopus, Health Source Nursing Academic Edition, EMBASE, and Web of Sciences were searched until the date of July 25, 2020. The analysis included an assessment of the overall incidence of OSA malignancies, the incidence of OSA malignancies by age and gender, and the incidence of different types of malignancies in patients with OSA. The total rate and the corresponding 95% confidence interval (CI) of the incidence of malignant tumors in patients with OSA were calculated. Patients with OSA were classified according to age, gender, and different types of malignant tumors for meta-analysis.

RESULTS

A total of 12 studies involving 862,820 participants were included in this meta-analysis. Random effect model analysis showed that the total incidence of malignant tumors in patients with OSA was 0.046% (95% CI: 0.027-0.065, P < 0.001), higher than that of malignant tumors in the general population. According to the analytical results classified by gender, the incidence of malignant tumor in female patients with OSA was 4.0% (95% CI: 0.014-0.066), higher than that in male patients at 3.5% (95% CI: 0.012-0.058). The analytical results classified by age showed that the incidence of malignant tumors in patients with OSA aged below 60 years was 1.8% (95% CI: 0.000-0.036), lower than that in patients aged above 60 years at 4.3% (95% CI: 0.002-0.084). The analytical results classified by the types of malignant tumors showed that the incidences of breast cancer, lung cancer, colorectal cancer, prostate cancer, kidney cancer, pancreatic cancer, and melanoma in patients with OSA were 0.5% (95% CI: 0.001-0.008), 0.5% (95% CI: 0.002-0.009), 0.5% (95% CI: 0.003-0.008), 1.1% (95% CI: 0.002-0.021), 0.3% (95% CI: 0.001-0.005), 0.1% (95% CI: 0.001-0.002), and 0.4% (95% CI: 0.003-0.005), respectively. Among them, the incidence of prostate cancer was the highest, followed by breast cancer, lung cancer, colorectal cancer, melanoma, and kidney cancer, whereas the incidence of pancreatic cancer was the lowest. However, the incidence of specific malignant tumors in patients with OSA did not have a significant increase compared with that in the general population.

CONCLUSIONS

The analytical results of this meta-analysis suggested that OSA may be associated with an overall increase in the incidence of malignancies based on the currently available data, but the connection with specific types of malignancies was not significant. Further studies are needed to explore this association in the future.

Association between obstructive sleep apnea and thyroid cancer incidence: a national health insurance data study

PURPOSE

Little is known about the incidence of thyroid cancer in patients with obstructive sleep apnea (OSA). This study aimed to evaluate whether OSA is associated with the incidence of thyroid cancer based on the Korea National Health Insurance Service (KNHIS) database.

METHODS

This study was designed as a retrospective cohort data analysis of the KNHIS dataset. A total of 198,574 patients who were over 20 years of age and had been newly diagnosed with OSA between 2007 and 2014 were enrolled. A control group of 992,870 individuals was selected based on propensity score matching by age and sex. The mean follow-up duration was 4.5 ± 2.3 years. The primary endpoint was the incidence of newly diagnosed thyroid cancer.

RESULTS

The hazard ratio (HR) for thyroid cancer incidence among OSA patients compared to the control was 1.72 (95% confidence interval [CI] 1.60-1.84) based on Model 1 (not adjusted by any covariate) and 1.64 (95% CI 1.53-1.76) based on Model 2 (adjusted by income level, diabetes, hypertension, and dyslipidemia). Thyroid cancer incidence was significantly higher in male patients (HR = 1.93, 95% CI 1.74-2.12) than female ones (HR = 1.39, 95% CI 1.26-1.54). When compared by age, the HR of thyroid cancer was higher in middle-aged (40 ≤ age < 65 years) patients (HR = 1.68, 95% CI 1.55-1.83) than in young (20 ≤ age < 40 years, HR = 1.53, 95% CI 1.32-1.77) or old (65 ≤ age, HR = 1.28, 95% CI 0.94-1.74) patients.

CONCLUSION

OSA may increase the risk of developing thyroid cancer, especially in middle-aged men.

Sleep apnoea and incident malignancy in type 2 diabetes

Background

Sleep apnoea and type 2 diabetes (T2D) have been linked to malignancy. The aim of the present study was to evaluate the association between sleep apnoea and incidence of malignancy in patients with T2D.

Methods

The DIACORE (DIAbetes COhoRtE) study is a prospective, population-based cohort study in T2D patients. In the sleep disordered breathing substudy, the apnoea–hypopnoea index (AHI), oxygen desaturation index (ODI) and percentage of night-time spent with a peripheral oxygen saturation of <90% (t_sat90%) were assessed using a two-channel ambulatory monitoring device. Malignancy diagnoses were gathered using self-reported medical history data validated by medical records. Hazard ratios (HRs) for incident malignancy were derived by Cox regression adjusting for sex, age, body mass index, smoking status, alcohol intake, socioeconomic status and HbA1c.

Results

Of 1239 patients with T2D (mean age 67 years, 41% female, mean body mass index 30.9 kg·m⁻²), 79 (6.4%) were first-time diagnosed with a malignancy within a median follow-up period of 2.7 years (interquartile range 2.2–4.5 years). AHI, ODI and t_sat90% were not associated with incident malignancy. In subgroup analysis, females showed increased cancer risk per AHI unit (adjusted HR 1.03 per AHI unit, 95% CI 1.00–1.06; p=0.028) and severe sleep apnoea (defined as AHI ≥30 events·h⁻¹; adjusted HR 4.19, 95% CI 1.39–12.77; p=0.012). This was not seen in males, and a significant interaction was observed (interaction terms p=0.048 and p=0.033, respectively).

Conclusion

Sleep apnoea was not associated with incident malignancy in T2D patients. However, stratified analysis revealed a significant association between sleep apnoea and incident malignancy in females, but not in males.

In patients with type 2 diabetes, sleep apnoea is not associated with the incidence of malignancy. However, stratified analysis shows that sleep apnoea is associated with incident malignancy in females, but not in males.https://bit.ly/37RAK8V

Associations of self-reported obstructive sleep apnea with total and site-specific cancer risk in older women: a prospective study

BACKGROUND AND OBJECTIVES

Chronic intermittent hypoxia resulting from obstructive sleep apnea (OSA) may activate multiple carcinogenic pathways and lead to cancer development.

METHODS

We prospectively examined the association between OSA and cancer risk among 65,330 women in the Nurses' Health Study who were free of cancer in 2008 (mean age: 73.3 years). Incident cancer diagnoses were collected until 2016 and confirmed by pathology reports. Clinically diagnosed OSA was self-reported in 2008 and updated in 2012. We used time-dependent Cox regression to estimate hazard ratios (HR) for the associations of OSA with total and site-specific cancer risk.

RESULTS

We documented 5,257 incident cancer diagnoses during follow-up. In the age-adjusted model, OSA was associated with a 15% (95% CI: 1.03, 1.29) increase in total cancer risk. The association became nonsignificant after adjustment for multiple cancer risk factors (HR: 1.08; 95% CI: 0.96, 1.21). When examining cancer risk by site, OSA was associated with significantly increased risk for lung (fully adjusted HR: 1.52; 95% CI: 1.07, 2.17), bladder (fully adjusted HR: 1.94; 95% CI: 1.12, 3.35), and thyroid cancer (fully adjusted HR: 2.06; 95% CI: 1.01, 4.22) and possibly increased risk for kidney cancer (fully adjusted HR: 1.59; 95% CI: 0.84, 3.01). When grouping cancer sites by risk factor profiles, OSA was positively associated with smoking-related cancers (fully adjusted HR: 1.37; 95% CI: 1.11, 1.67), and this association was stronger in never smokers than ever smokers.

CONCLUSION

While OSA was not independently associated with overall cancer risk in older women, significant associations were observed for smoking-related cancers, especially in nonsmokers.

Differential effect of intermittent hypoxia and sleep fragmentation on PD-1/PD-L1 upregulation

Immunosurveillance is compromised in patients with obstructive sleep apnea (OSA) as reflected by overexpression of the programmed death cell receptor and its ligand (PD-1/PD-L1) coinhibitory axis. However, the contributions of intermittent hypoxia (IH) and sleep fragmentation (SF) are unclear. We therefore evaluated the expression of PD-1 and PD-L1 on immune cells from mice subjected to IH or SF, and in human cells exposed to IH, oxidative stress, or both conditions. Six-week-old male C57BL/6J mice were exposed to either IH or SF using previously established in vivo models. Moreover, human peripheral blood mononuclear cells (PBMC) were cultured overnight under normoxia, IH, hydrogen peroxide (H2O2), or both. Murine splenocytes and human PBMC were isolated, and labeled using surface-specific antibodies for flow cytometry analysis. Compared to control mice, IH induced higher expression of PD-L1 on F4/80 cells and of PD-1 on CD4+ and CD8+ T-cells, whereas no significant changes emerged after SF. In vitro models of IH and oxidative stress showed similar changes for expression of PD-L1 on human monocytes and PD-1 on CD4+ T-cells. Furthermore, H2O2 increased PD-1 expression on CD8+ T-cells, compromising their cytotoxic capacity assessed by perforin expression, similar to IH. No evidence of synergistic effects was apparent. Therefore, PD-1/PD-L1 upregulation reported in patients with OSA appears to be preferentially mediated by IH rather than SF.

Survival benefit of continuous positive airway pressure in Japanese patients with obstructive sleep apnea: a propensity-score matching analysis

STUDY OBJECTIVES

Continuous positive airway pressure (CPAP) improves quality of life in patients with obstructive sleep apneas. However, the long-term benefit in all-cause mortality and cardiovascular death are limited among Japanese.

METHODS

We conducted a retrospective study of patients treated in our sleep clinic in Okinawa, Japan. All patients with full-scale polysomnography from September 1990 to December 2010 were investigated in terms of outcomes such as death (dates and causes of death) between 2012 and 2013 by chart review, telephone calls, and letters of inquiry. Propensity-score matching was performed to balance baseline characteristic differences between a CPAP user group and a nonuser group. The primary outcomes were all-cause mortality and a composite of cardiovascular disease mortality, such as heart disease and stroke, between the two groups.

RESULTS

The CPAP user group, almost double in number, had more severe obstructive sleep apnea, more comorbidities, smoking, and alcohol consumption compared to the nonuser group but no significant difference in Epworth Sleepiness Scale. Propensity-score matching selected 1,274 of 4,519 patients as the CPAP user group and 1,274 of 2,128 as the CPAP nonuser group. Mean age of the patients was 52.3 (±13.5) years and 79% were men. After a median follow-up of 79 (interquartile interval, 24 to 128) months in the CPAP user group and 73.5 (interquartile interval, 26 to 111) in the non-CPAP group, death from all causes occurred in 53 (4.2%) patients in CPAP user group and in 94 (7.4%) patients in CPAP nonuser group. The leading cause of death was malignancy in each group. The hazard ratios for all-cause mortality and cardiovascular disease deaths were 0.56 (95% confidence interval (CI), 0.41-0.78) and 0.54 (95% CI, 0.28-1.03) between CPAP user group and CPAP nonuser group, respectively.

CONCLUSIONS

In obstructive sleep apnea patients, CPAP use was associated with lower all-cause mortality.

Risk of mortality among patients with moderate to severe obstructive sleep apnea and diabetes mellitus: results from the SantOSA cohort

INTRODUCTION

Patients with obstructive sleep apnea (OSA) and comorbid diabetes mellitus (DM) are reported to have an increased risk of cardiovascular (CV) outcomes; however, data on CV mortality are scant.

AIM

This study aimed to evaluate if patients with comorbid OSA and DM have an increased risk of CV mortality that is higher than the two diseases in isolation.

METHODS

In this prospective cohort study, we included patients referred for a sleep study with and without DM at baseline. We developed four study groups as follows: group 1 (reference group), OSA (-) DM (-); group 2, OSA (-) DM (+); group 3, OSA (+) DM (-); group 4, OSA (+) DM (+). Intergroup differences were evaluated using the t test and χ² test, and multivariate analysis was performed using logistic regression. The incidence rates of CV mortality were calculated using the Kaplan-Meier (log-rank) model, and adjusted HRs were calculated using the Cox regression model.

RESULTS

A total of 1447 patients were included in the analysis-group 1: 441 participants; group 2: 141 participants; group 3: 736 participants; group 4: 151 participants. The mean follow-up was 5 years. The association between OSA + DM showed an independent risk of incident CV mortality (HR 2.37, CI 1.16-4.82, p = 0.02) and an increased prevalence of coronary heart disease (OR 3.44, CI 1.73-5.59, p < 0.01). In addition, T90% was also associated with CV mortality.

CONCLUSION

The coexistence of OSA + DM was associated with an independent risk of CV mortality. In addition, T90% was also associated with CV mortality.

Obstructive Sleep Apnea Worsens Progression-Free and Overall Survival in Human Metastatic Colorectal Carcinoma

Sleep disorders have emerged as highly prevalent conditions, and along with improved understanding of such disorders, increased attention has gained the evidence that perturbation in sleep architecture and continuity may initiate, exacerbate, or modulate the phenotypic expression of multiple diseases including cancer. Furthermore, obstructive sleep apnea (OSA) has recently been implicated in increased incidence and more adverse prognosis of cancer in humans. This study was designed to confirm the high prevalence of OSA in human malignancies and assess its prognostic relevance in metastatic colorectal carcinomas (mCRCs). A prospective cohort of 52 subjects, affected by solid histologically confirmed metastatic malignancies, was analyzed, and among them, 29 mCRCs were studied for the prognostic role of OSA. OSA was diagnosed in 34.6% (18/52) of patients with a statistically significant difference in apnea-hyponea index between OSA and non-OSA subgroups (14.2 ± 12.2 vs. 2.1 ± 1.5, p < 0.01). Consistently, OSA was diagnosed in 34.5% (10/29) of mCRCs with lower rates of first-line therapy disease control in OSA compared to non-OSA patients (60% in OSA vs. 94.7% in non-OSA, p=0.03). Of note, progression-free and overall survival rates were significantly shorter in OSA (respectively, 9 and 22 months) compared non-OSA (20 and 40 months) mCRC patients (HR = 2.63; 95% CI 0.88-7.84, p=0.01 for PFS; HR = 3.93; 95% CI 1.13-13.73, p < 0.001 for OS). Finally, the multivariate analysis showed that OSA is an independent prognostic factor for PFS (p=0.0076) and OS (p=0.0017) in this cohort. Altogether, these data suggest that OSA is a potential clinical marker predictor of poor prognosis in patients with mCRC.

Obstructive Sleep Apnea and Incident Cancer: A Large Retrospective Multicenter Clinical Cohort Study

BACKGROUND

To examine the association between the severity of obstructive sleep apnea (OSA) and nocturnal hypoxemia with incident cancer.

METHODS

This was a multicenter retrospective clinical cohort study using linked clinical and provincial health administrative data on consecutive adults who underwent a diagnostic sleep study between 1994 and 2017 in four academic hospitals (Canada) who were free of cancer at baseline. Cancer status was derived from the Ontario Cancer Registry. Cox cause-specific regressions were utilized to address the objective and to calculate the 10-year absolute risk difference (ARD) in the marginal probability of incident cancer and the number needed to harm (NNH).

RESULTS

Of 33,997 individuals considered, 33,711 with no missing OSA severity were included: median age, 50 years; 58% male; and 23% with severe OSA (apnea-hypopnea index >30). Of the 18,458 individuals with information on sleep time spent with oxygen saturation (SaO₂) <90%, 5% spent >30% of sleep with SaO₂ <90% (severe nocturnal hypoxemia). Over a median of 7 years, 2,498 of 33,711 (7%) individuals developed cancer, with an incidence rate of 10.3 (10.0-10.8) per 1,000 person-years. Controlling for confounders, severe OSA was associated with a 15% increased hazard of developing cancer compared with no OSA (HR = 1.15, 1.02-1.30; ARD = 1.28%, 0.20-2.37; and NNH = 78). Severe hypoxemia was associated with about 30% increased hazard (HR = 1.32, 1.08-1.61; ARD = 2.38%, 0.47-4.31; and NNH = 42).

CONCLUSIONS

In a large cohort of individuals with suspected OSA free of cancer at baseline, the severity of OSA and nocturnal hypoxemia was independently associated with incident cancer.

IMPACT

These findings suggest the need for more targeted cancer risk awareness in individuals with OSA.

Sleep disorders and cancer: State of the art and future perspectives

A bidirectional connection between sleep and cancer exists; however, the specific associations between individual sleep disorders and particular tumors are not very clear. An accurate assessment of sleep disorders in cancer patients is necessary to improve patient health, survival, response to therapy, quality of life, reduction of comorbidities/complications. Indeed, recent scientific evidence shows that knowledge and management of sleep disorders offer interesting therapeutic perspectives for the treatment of cancer. In light of this need, the objective of this review is to assess the evidence highlighted in the research of the last ten years on the correlation between each specific category of sleep disorder according to the International Classification of Sleep Disorders 3rd Ed. and several types of tumor based on their anatomical location (head-neck, including the brain and thyroid; lung; breast; ovary; endometrium; testes; prostate; bladder; kidney; gastrointestinal tract, subdivided into: stomach, liver, colon, pancreas; skin; bone tumors; hematological malignancies: leukemia, lymphoma, multiple myeloma, polycythemia), in order to evaluate what is currently known about: 1) sleep disorders as cancer risk factor; 2) tumors associated with the onset of sleep disorders; 3) targeted therapies of sleep disorders in cancer patients and new oncological perspectives following the evaluation of sleep.

Sleep Apnoea Adverse Effects on Cancer: True, False, or Too Many Confounders?

Obstructive sleep apnoea (OSA) is a prevalent disorder associated with increased cardiovascular, metabolic and neurocognitive morbidity. Recently, an increasing number of basic, clinical and epidemiological reports have suggested that OSA may also increase the risk of cancer, and adversely impact cancer progression and outcomes. This hypothesis is convincingly supported by biological evidence linking certain solid tumours and hypoxia, as well as by experimental studies involving cell and animal models testing the effects of intermittent hypoxia and sleep fragmentation that characterize OSA. However, the clinical and epidemiological studies do not conclusively confirm that OSA adversely affects cancer, even if they hold true for specific cancers such as melanoma. It is likely that the inconclusive studies reflect that they were not specifically designed to test the hypothesis or because of the heterogeneity of the relationship of OSA with different cancer types or even sub-types. This review critically focusses on the extant basic, clinical, and epidemiological evidence while formulating proposed directions on how the field may move forward.

The incidence of malignant brain tumors is increased in patients with obstructive sleep apnea: A national health insurance survey

The association between obstructive sleep apnea (OSA) and malignant brain tumors has yet to be fully investigated. Therefore, the purpose of this study was to elucidate the effect of OSA on brain tumor incidence based on the Korea National Health Insurance Service (KNHIS) dataset. The KNHIS data between 2007 and 2014 were analyzed, and the primary endpoint was newly diagnosed malignant brain tumor. A total of 198,574 subjects aged ≥ 20 years with newly diagnosed OSA were enrolled in the study, and 992,870 individuals were selected as a control group based on propensity score matching (PSM) by gender and age. The average follow-up duration was 4.8 ± 2.3 years. The hazard ratios (HRs) for brain tumor for patients with OSA were 1.78 (95% confidence interval [CI]: 1.42-2.21) in Model 1 (not adjusted with any covariate) and 1.67 (95% CI: 1.34-2.09) in Model 2 (adjusted for income level, diabetes, hypertension, dyslipidemia, and COPD). In subgroup analysis by gender, the odds ratios (OR) of OSA were 1.82 (95% CI: 1.41-2.33) in men and 1.26 (95% CI: 0.74-2.03) in women. The ORs were 1.97 (95% CI: 1.15-3.24) in the older (age ≥ 65 years) group, 1.66 (95% CI: 1.25-2.17) in the middle-aged (40 ≤ age < 65 years) group, and 1.41 (0.78-2.44) in the young (20 ≤ age < 40 years) group. In conclusion, OSA may increase the incidence of brain tumors.

Differential Gene Expression in Brain and Liver Tissue of Wistar Rats after Rapid Eye Movement Sleep Deprivation

Sleep is essential for the survival of most living beings. Numerous researchers have identified a series of genes that are thought to regulate "sleep-state" or the "deprived state". As sleep has a significant effect on physiology, we believe that lack of total sleep, or particularly rapid eye movement (REM) sleep, for a prolonged period would have a profound impact on various body tissues. Therefore, using the microarray method, we sought to determine which genes and processes are affected in the brain and liver of rats following nine days of REM sleep deprivation. Our findings showed that REM sleep deprivation affected a total of 652 genes in the brain and 426 genes in the liver. Only 23 genes were affected commonly, 10 oppositely, and 13 similarly across brain and liver tissue. Our results suggest that nine-day REM sleep deprivation differentially affects genes and processes in the brain and liver of rats.

Role of the Cyclooxygenase Pathway in the Association of Obstructive Sleep Apnea and Cancer

The objective of this review is to examine the findings that link obstructive sleep apnea (OSA) with cancer and the role played by the cyclooxygenase (COX) pathway in this association. Epidemiological studies in humans suggest a link between OSA and increased cancer incidence and mortality. Studies carried out in animal models have shown that intermittent hypoxia (IH) induces changes in several signaling pathways involved in the regulation of host immunological surveillance that results in tumor establishment and invasion. IH induces the expression of cyclooxygenase 2 (COX-2) that results in an increased synthesis of prostaglandin E2 (PGE2). PGE2 modulates the function of multiple cells involved in immune responses including T lymphocytes, NK cells, dendritic cells, macrophages, and myeloid-derived suppressor cells. In a mouse model blockage of COX-2/PGE2 abrogated the pro-oncogenic effects of IH. Despite the fact that aspirin inhibits PGE2 production and prevents the development of cancer, none of the epidemiological studies that investigated the association of OSA and cancer included aspirin use in the analysis. Studies are needed to investigate the regulation of the COX-2/PGE2 pathway and PGE2 production in patients with OSA, to better define the role of this axis in the physiopathology of OSA and the potential role of aspirin in preventing the development of cancer.

The effect of intermittent hypoxia and fecal microbiota of OSAS on genes associated with colorectal cancer

Purpose

Colorectal cancer (CRC) is one of the common causes of cancer death worldwide. Obstructive sleep apnea syndrome (OSAS), sharing many risk factors in common with CRC, is prevalent among CRC patients. OSAS may promote the CRC development independently but the mechanism is still unknown. Intermittent hypoxia (IH) is one of the characteristics of OSAS, and hypoxia may influence the genes associated with CRC. Intestinal microbiota plays important role in CRC carcinogenesis, and OSAS patients have been shown to have intestinal microbiota dysbiosis. We hypothesized that IH and intestinal microbiota dysbiosis may be involved for CRC in patients with OSAS.

Methods

We established precancerous cell models of CRC with Immorto-Min colonic epithelial (IMCE) cells. First, the cells were exposed to IH in a special chamber for 4 h, 8 h, and 12 h. Feces from 6 patients with OSAS and 6 healthy controls were collected and made into sterile fecal fluid for incubation with IMCE cells for 12 h. The cells were then exposed to IH for 4 h, 8 h, and 12 h. After IH exposure, the expressions of genes and inflammation cytokines associated with CRC, such as β-catenin, STAT3, HIF-1α, IL-6, TNF-α, c-myc, and cyclinD1, were tested.

Results

IH activated the expression of HIF-1α and STAT3 both in mRNA and protein level (HIF-1α: P = 0.015 for mRNA level, P = 0.027 for protein level; STAT3: P = 0.023 for mRNA level, P = 0.023 for protein level), and promoted p-STAT3 shifting to the nucleus (P = 0.023). The mRNA of β-catenin (P = 0.022) and cyclinD1 (P = 0.023) was elevated, but there was no change for the β-catenin protein in the nucleus. Gut microbiota of OSAS patients promoted the expression of STAT3 (protein level: 0 h: P = 0.037; 4 h: P = 0.046; 8 h: P = 0.049; 12 h: P = 0.037), promoted p-STAT3 (4 h: P = 0.049; 8 h: P = 0.046; 12 h: P = 0.046) shifting to the nucleus, and also elevated the expression of IL-6 and TNF-α in mRNA level at 4 h (IL-6: P = 0.037, TNF-α: P = 0.037) and 8 h (IL-6: P = 0.037, TNF-α: P = 0.037). The protein of β-catenin in the nucleus was not affected by IH and gut microbiota from OSAS.

Conclusions

Our study demonstrated that IH and gut microbiota of patients with OSAS activated HIF-1α expression and STAT3 pathway in IMCE cells, with no influence on β-catenin pathway, which suggested that IH, STAT3 pathway, chronic inflammation, and intestinal microbiota dysbiosis may be involved in CRC carcinogenesis correlated with OSAS These findings must be interpreted cautiously and further research is necessary to clarify the causative steps in CRC development.

Obstructive sleep apnea and cancer: a complex relationship

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) has been recognized as a risk factor for cancer mainly through hypoxia, based on studies that did not distinguish among cancer types. The purpose of this review is to discuss the most recent data on epidemiology and pathophysiology of the OSA-cancer association.

RECENT FINDINGS

According to epidemiological studies, OSA may have different influences on each type of cancer, either increasing or decreasing its incidence and aggressiveness. Time spent with oxygen saturation below 90% appears the polysomnographic variable most strongly associated with unfavorable effects on cancer. Experimental studies support the role of hypoxia as an important risk factor for cancer growth and aggressiveness, especially when it shows an intermittent pattern. These effects are largely mediated by the hypoxia-inducible factor, which controls the synthesis of molecules with effects on inflammation, immune surveillance and cell proliferation. Sleep fragmentation participates in increasing cancer risk. Modulating effects of age remain controversial.

SUMMARY

Effects of OSA on cancer may largely vary among neoplastic diseases, both in their magnitude and direction. The worse risk associated with intermittent rather than persistent hypoxia, and the effects of OSA therapy on cancer natural history are still poorly known, and deserve new careful studies.

Blood and urine biomarkers associated with long-term respiratory dysfunction following neonatal hyperoxia exposure: Implications for prematurity and risk of SIDS

Former preterm infants, many of whom required supplemental O₂ support, exhibit sleep disordered breathing and attenuated ventilatory responses to acute hypoxia (HVR) beyond their NICU stay. There is an increasing awareness that early detection of biomarkers in biological fluids may be useful predictors/identifiers of short- and long-term morbidities. In the present study, we identified serotonin (5-HT), dopamine (DA) and hyaluronan (HA) as three potential biomarkers that may be increased by neonatal hyperoxia and tested whether they would be associated with an impaired HVR in a rat model of supplemental O₂ exposure. Neonatal rats (postnatal age (P) 6 days, P6) exposed to hyperoxia (40% FIO₂, 24 h/day between P1-P5 days of age) exhibited an attenuated early (1 min), but not the late (4-5 min) phase of the HVR compared to normoxia control rats; the attenuated early phase HVR was associated with increased levels of DA (urine and serum), 5-HT (platelet poor plasma only, PPP), and HA (serum only). At P21, both the early and late phases of the HVR were attenuated, but serum and urine levels of all 3 biomarkers were similar to age-matched control rats. These data indicate that changes in several serum and/or urine biomarkers (5-HT, DA, and HA) following short-term (days) neonatal hyperoxia can signify long-term (weeks) respiratory control dysfunction. Further studies are needed to determine whether early detection of similar biomarkers could be convenient predictors of increased risk of abnormalities in respiratory control including sleep disordered breathing in former preterm infants who had received prior supplemental O₂ and who might also be at increased risk of SIDS.

Five-year relative survival in sleep apnea patients with a subsequent cancer diagnosis

STUDY OBJECTIVES

In vitro and animal studies suggest that intermittent hypoxia characterizing sleep apnea contributes to accelerated cancer progression. However, the impact of sleep apnea on survival subsequent to cancer diagnosis is unknown.

METHODS

We identified a cohort of 1,575 adults diagnosed with sleep apnea between 2005 and 2014 with a subsequent cancer diagnosis via linkage of the University of Washington Medicine system and a population-based cancer registry serving the same Seattle-Puget Sound region. We computed age-standardized 5-year relative survival after cancer diagnosis for all cancers combined, and for specific cancer sites, for both the sleep apnea cohort and the general Seattle-Puget Sound population, and we used US life tables as the reference population. Relative survival was estimated by sex, cancer stage, and health care engagement.

RESULTS

Five-year overall relative survival for cancer was more favorable in the sleep apnea cohort than in the general population [83.6%, 95% confidence interval (CI): 79.8%-86.8% vs 71.6%, 95% CI: 71.3%-71.9%]; this pattern was applicable to most specific cancer sites. However, 5-year relative survival was slightly less favorable in the sleep apnea cohort among patients with melanoma (97.7%, 95% CI: 84.6%-99.7% vs 99.2%, 95% CI: 98.8%-99.5%) and cancer of the corpus uteri (84.0%, 95% CI: 58.2%-94.5% vs 84.6%, 95% CI: 83.1%-86.0%).

CONCLUSIONS

The fact that survival after cancer, overall and for most cancer sites, was more favorable in patients with sleep apnea warrants larger community-based studies to further tease out effects of sleep apnea and treatment on site-specific survival for different cancer types, particularly in patients with melanoma or uterine cancer.