Association between obstructive sleep apnoea and cancer: a cross-sectional, population-based study of the DISCOVERY cohort

OBJECTIVES

Nocturnal hypoxia in obstructive sleep apnoea (OSA) is a potential risk factor for cancer. We aimed to investigate the association between OSA measures and cancer prevalence in a large national patient cohort.

DESIGN

Cross-sectional study.

SETTINGS

44 sleep centres in Sweden.

PARTICIPANTS

62 811 patients from the Swedish registry for positive airway pressure (PAP) treatment in OSA, linked to the national cancer registry and national socioeconomic data (the course of DIsease in patients reported to Swedish CPAP, Oxygen and VEntilator RegistrY cohort).

OUTCOME MEASURES

After propensity score matching for relevant confounders (anthropometric data, comorbidities, socioeconomic status, smoking prevalence), sleep apnoea severity, measured as Apnoea-Hypopnoea Index (AHI) or Oxygen Desaturation Index (ODI), were compared between those with and without cancer diagnosis up to 5 years prior to PAP initiation. Subgroup analysis for cancer subtype was performed.

RESULTS

OSA patients with cancer (n=2093) (29.8% females, age 65.3 (SD 10.1) years, body mass index 30 (IQR 27-34) kg/m²) had higher median AHI (n/hour) (32 (IQR 20-50) vs 30 (IQR 19-45), n/hour, p=0.002) and median ODI (n/hour) (28 (IQR 17-46) vs 26 (IQR 16-41), p<0.001) when compared with matched OSA patients without cancer. In subgroup analysis, ODI was significantly higher in OSA patients with lung cancer (N=57; 38 (21-61) vs 27 (16-43), p=0.012)), prostate cancer (N=617; 28 (17-46) vs 24, (16-39)p=0.005) and malignant melanoma (N=170; 32 (17-46) vs 25 (14-41),p=0.015).

CONCLUSIONS

OSA mediated intermittent hypoxia was independently associated with cancer prevalence in this large, national cohort. Future longitudinal studies are warranted to study the potential protective influence of OSA treatment on cancer incidence.

Exploring the most important factors related to self-perceived health among older men in Sweden: a cross-sectional study using machine learning

OBJECTIVE

To evaluate which factors are the most strongly related to self-perceived health among older men and describe the shape of the association between the related factors and self-perceived health using machine learning.

DESIGN AND SETTING

This is a cross-sectional study within the population-based VAScular and Chronic Obstructive Lung disease study (VASCOL) conducted in southern Sweden in 2019.

PARTICIPANTS

A total of 475 older men aged 73 years from the VASCOL dataset.

MEASURES

Self-perceived health was measured using the first item of the Short Form 12. An extreme gradient-boosting model was trained to classify self-perceived health as better (rated: excellent or very good) or worse (rated: fair or poor) using self-reported data on 19 prevalent physician-diagnosed health conditions, intensity of 9 symptoms and 9 demographic and lifestyle factors. Importance of factors was measured in SHapley Additive exPlanations absolute mean and higher scores correspond to greater importance.

RESULTS

The most important factors for classifying self-perceived health were: pain (0.629), sleep quality (0.595), breathlessness (0.549), fatigue (0.542) and depression (0.526). Health conditions ranked well below symptoms and lifestyle variables. Low levels of symptoms, good sleep quality, regular exercise, alcohol consumption and a body mass index between 22 and 28 were associated with better self-perceived health.

CONCLUSIONS

Symptoms are more strongly related to self-perceived health than health conditions, which suggests that the impacts of health conditions are mediated through symptoms, which could be important targets to improve self-perceived health. Machine learning offers a new way to assess composite constructs such as well-being or quality of life.

Chronic breathlessness and sleep problems: a population-based survey

OBJECTIVES

This study aimed to explore the relationship (presence and severity) between chronic breathlessness and sleep problems, independently of diagnoses and health service contact by surveying a large, representative sample of the general population.

SETTING

Analysis of the 2017 South Australian Health Omnibus Survey, an annual, cross-sectional, face-to-face, multistage, clustered area systematic sampling survey carried out in Spring 2017.Chronic breathlessness was self-reported using the ordinal modified Medical Research Council (mMRC; scores 0 (none) to 4 (housebound)) where breathlessness has been present for more than 3 of the previous 6 months. 'Sleep problems-ever' and 'sleep problem-current' were assessed dichotomously. Regression models were adjusted for age; sex and body mass index (BMI).

RESULTS

2900 responses were available (mean age 48.2 years (SD=18.6); 51% were female; mean BMI 27. 1 (SD=5.9)). Prevalence was: 2.7% (n=78) sleep problems-past; 6.8% (n=198) sleep problems-current and breathlessness (mMRC 1-4) was 8.8% (n=254). Respondents with sleep problemspast were more likely to be breathless, older with a higher BMI and sleep problems-present also included a higher likelihood of being female.After adjusting for age, sex and BMI, respondents with chronic breathlessness had 1.9 (95% CI=1.0 to 3.5) times the odds of sleep problems-past and sleep problems-current (adjusted OR=2.3; 95% CI=1.6 to 3.3).

CONCLUSIONS

There is a strong association between the two prevalent conditions. Future work will seek to understand if there is a causal relationship using validated sleep assessment tools and whether better managing one condition improves the other.

VAScular and Chronic Obstructive Lung disease (VASCOL): a longitudinal study on morbidity, symptoms and quality of life among older men in Blekinge county, Sweden

PURPOSE

Despite data showing breathlessness to be more prevalent in older adults, we have little detail about the severity or multidimensional characteristics of breathlessness and other self-reported measures (such as quality of life and other cardiorespiratory-related symptoms) in this group at the population level. We also know little about the relationship between multidimensional breathlessness, other symptoms, comorbidities and future clinical outcomes such as quality of life, hospitalisation and mortality. This paper reports the design and descriptive findings from the first two waves of a longitudinal prospective cohort study in older adults.

PARTICIPANTS

Between 2010 and 2011, 1900 men in a region in southern Sweden aged 65 years were invited to attend for VAScular and Chronic Obstructive Lung disease (VASCOL) baseline (Wave 1) assessments which included physiological measurements, blood sampling and a self-report survey of lifestyle and previous medical conditions. In 2019, follow-up postal survey data (Wave 2) were collected with additional self-report measures for breathlessness, other symptoms and quality of life. At each wave, data are cross-linked with nationwide Swedish registry data of diseases, treatment, hospitalisation and cause of death.

FINDINGS TO DATE

1302/1900 (68%) of invited men participated in Wave 1, which include 56% of all 65-year-old men in the region. 5% reported asthma, 2% chronic obstructive pulmonary disease, 56% hypertension, 10% diabetes and 19% had airflow limitation. The VASCOL cohort had comparable characteristics to those of similarly aged men in Sweden. By 2019, 109/1302 (8.4%) had died. 907/1193 (76%) of the remainder participated in Wave 2. Internal data completeness of 95% or more was achieved for most Wave 2 measures.

FUTURE PLANS

A third wave will be conducted within 4 years, and the cohort will be followed through repeated follow-ups planned every fourth year, as well as national registry data of diagnosis, treatments and cause of death.

Ambulatory oxygen for treatment of exertional hypoxaemia in pulmonary fibrosis (PFOX trial): a randomised controlled trial

INTRODUCTION

Interstitial lung diseases are characterised by scarring of lung tissue that leads to reduced transfer of oxygen into the blood, decreased exercise capacity and premature death. Ambulatory oxygen therapy may be used to treat exertional oxyhaemoglobin desaturation, but there is little evidence to support its efficacy and there is wide variation in clinical practice. This study aims to compare the clinical efficacy and cost-effectiveness of ambulatory oxygen versus ambulatory air in people with fibrotic interstitial lung disease and exertional desaturation.

METHODS AND ANALYSIS

A randomised, controlled trial with blinding of participants, clinicians and researchers will be conducted at trial sites in Australia and Sweden. Eligible participants will be randomised 1:1 into two groups. Intervention participants will receive ambulatory oxygen therapy using a portable oxygen concentrator (POC) during daily activities and control participants will use an identical POC modified to deliver air. Outcomes will be assessed at baseline, 3 months and 6 months. The primary outcome is change in physical activity measured by number of steps per day using a physical activity monitor (StepWatch). Secondary outcomes are functional capacity (6-minute walk distance), health-related quality of life (St George Respiratory Questionnaire, EQ-5D-5L and King's Brief Interstitial Lung Disease Questionnaire), breathlessness (Dyspnoea-12), fatigue (Fatigue Severity Scale), anxiety and depression (Hospital Anxiety and Depression Scale), physical activity level (GENEActive), oxygen saturation in daily life, POC usage, and plasma markers of skeletal muscle metabolism, systematic inflammation and oxidative stress. A cost-effectiveness evaluation will also be undertaken.

ETHICS AND DISSEMINATION

Ethical approval has been granted in Australia by Alfred Hospital Human Research Ethics Committee (HREC/18/Alfred/42) with governance approval at all Australian sites, and in Sweden (Lund Dnr: 2019-02963). The results will be published in peer-reviewed scientific journals, presented at conferences and disseminated to consumers in publications for lay audiences.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03737409).