Non-dipping nocturnal blood pressure correlates with obstructive sleep apnoea severity in normotensive subjects and may reverse with therapy.

BACKGROUND: Obstructive sleep apnoea (OSA) is strongly associated with systemic hypertension, but there are limited data on the relationship with blood pressure (BP) in normotensive subjects. Here, we examined the relationship of OSA with nocturnal BP in a documented diurnal normotensive cohort, explored potential intermediate pathways and assessed the effects on BP of continuous positive airways pressure (CPAP) therapy. METHODS: 65 males referred for assessment of possible OSA and normotensive on 24-hour BP monitoring underwent overnight inpatient polysomnography (age 41±7 years, body mass index (BMI) 34±6 kg·m-2, apnoea-hypopnoea index (AHI) 14 (interquartile range 5-26)). Urine and serum were assessed for markers of sympathetic activation, renin-angiotensin-aldosterone system activity, oxidative stress, endothelial function and systemic inflammation. In a subset of patients, 24-hour BP monitoring was repeated after CPAP therapy. RESULTS: Within this normotensive cohort, night-time systolic and diastolic BP and nocturnal BP dip were highest in the fourth OSA severity quartile (p<0.05). Nocturnal BP dip correlated with AHI (r=-0.327, p<0.05) and oxygen desaturation index (ODI) (r=-0.371, p<0.05), but only ODI was an independent predictor of BP dip (B=-0.351, p<0.01) and non-dipping status (B=0.046, p<0.05). Overnight urinary norepinephrine correlated with nocturnal systolic BP (r=0.387, p<0.01) with a trend towards correlation with systolic dipping (p=0.087). In 20 CPAP-treated patients, night-time systolic BP decreased (p<0.05) and mean nocturnal BP dip increased (p≤0.05). CONCLUSION: In this normotensive cohort, OSA severity was associated with higher nocturnal BP, which improved following CPAP therapy, and intermittent hypoxia was the most important OSA-related variable in this relationship.

A clinical investigation into the ability of subjects with lung disease to provide breath specimens using the EvidenzerIRL evidential breath analyser in alcohol intoxicant driving in criminal justice evidence.

The EvidenzerIRL instrument has been in use as an evidential breath analyser in the application of drink driving laws in the Republic of Ireland since 2011. The result of the analysis is used as evidence in prosecutions before the Courts in per se offences of driving under the influence of alcohol as distinct from screening results at the roadside. This study aims to assist doctors, lawyers and judges in assessing drivers' failure to provide valid evidential breath specimens. Since the introduction of the EvidenzerIRL, approximately 10% of evidential breath tests annually result in failure or refusal to provide a successful breath specimen, this is an offence under Irish road traffic laws. The presence of lung disease has been given as a reason for the driver failing to provide evidential breath specimens. The aim of this study is to assess the ability of subjects with lung disease to provide breath specimens using the EvidenzerIRL. Pulmonary function tests (PFT) were carried out on volunteers from outpatients of the pulmonary laboratory in St Vincent's University Hospital, Dublin (n = 58) and a control group with no underlying lung disease (n = 19). After the PFTs all volunteers were asked to provide breath specimens using the EvidenzerIRL. Fourteen (24%) out of 58 lung disease volunteers failed to provide a breath specimen, no one from the control group was unsuccessful. Thirteen females and one male volunteer could not successfully provide. Female volunteers were more likely to fail to provide than male volunteers. A significant difference was found between the median age of successful (62.2 years) and unsuccessful (69.2 years) lung disease volunteers. Only one PFT, percentage predicted of Forced Expiratory Volume in 1 second (FEV1), had a significant difference between the mean of successful (86.6%) and unsuccessful (66.5%) lung disease volunteers. A subject with lung disease was more likely to be successful than unsuccessful. Drivers' effort and operators' guidance through the process were found to be crucial parts to a successful outcome.

Impact of obstructive sleep apnoea on cognitive function in multiple sclerosis: A longitudinal study.

Cognitive impairment (CI) and fatigue are common in people with multiple sclerosis (MS), with well-known profound effects on quality of life. Sleep disorders, including obstructive sleep apnoea (OSA), are also common in MS patients. The presence of CI has previously been shown to strongly correlate with OSA diagnosed using polysomnography in MS. Treatment of OSA has not previously been investigated as a potential modality to improve cognition in MS patients. Therefore, we sought to investigate the potential effects of OSA treatment on both cognitive function and fatigue in MS patients. Twenty-three participants with MS reporting significant fatigue were enrolled. CI was assessed by the Brief International Cognitive Assessment in MS and the 3-second Paced Auditory Serial Addition Test. All participants underwent overnight polysomnography to assess for possible OSA. Cognitive and fatigue measures were repeated in those subsequently treated for OSA and in a comparative untreated sample. Seven participants (30%) had a diagnosis of OSA based on an apnoea-hypopnea index greater than 5 per hour, with no correlation between the presence of CI and OSA. Verbal learning at follow-up assessment was seen to improve significantly in those treated for OSA, compared with those who were not treated for a sleep disorder. This small study demonstrates the potential for OSA treatment to improve verbal learning in people with MS, larger studies are indicated to further investigate the potential for cognitive and fatigue improvement in people with MS through treatment of comorbid OSA.

A clinical investigation into the ability of subjects with a lung disease to provide breath specimens using the Dräger 6510.

In the enforcement of drink driving laws failing to provide a breath specimen for alcohol analysis at the roadside when requested by a Police Officer is an offence in many countries. Some drivers claim that a lung disease prevented their ability to be successful. This study aims to investigate the relationship between the presence of a lung disease and the ability to provide a successful breath specimen using the Dräger 6510 screening device. Sixty participants with lung disease and nineteen control participants underwent pulmonary function tests and were then tested with a Dräger 6510 screening device. Only one participant was unsuccessful using the Dräger 6510, this participant suffered from interstitial lung disease. The pulmonary function test results did not indicate if someone would be successful or how many attempts would be needed to be successful. The presence of a lung disease did not indicate if a driver would be unsuccessful however all participants were free from infection and the participants with a lung disease were stable at the time of testing. Correct instruction, subject cooperation and the technique used by the driver to provide a breath specimen were found to be important factors in the success of a breath test.

Relationship between pulmonary hyperinflation and dyspnoea severity during acute exacerbations of cystic fibrosis.

BACKGROUND AND OBJECTIVE: Acute exacerbations of cystic fibrosis (CF) occur frequently throughout the course of the disease. Dyspnoea is the most common and distressing symptom experienced by patients during these episodes. We tested the hypothesis that pulmonary hyperinflation is an important determinant of dyspnoea severity during acute exacerbations. METHODS: We studied patients during an acute exacerbation of CF. Lung volumes, spirometry and dyspnoea scores were measured at Day 0, Day 7, at the end of treatment (EOT) and 14 days following the EOT. RESULTS: At the start of treatment, mean residual volume (RV)/total lung capacity (TLC) was 54.9%, which decreased significantly with treatment, as did vital capacity (VC), inspiratory capacity (IC) and dyspnoea scores. IC was the only independent predictor of dyspnoea severity. CONCLUSION: Our study demonstrates significant improvements in hyperinflation, spirometry and dyspnoea scores with treatment of acute exacerbations of CF. Hyperinflation, rather than airflow limitation, may contribute towards the increased dyspnoea during exacerbations.

Invariant Natural Killer T Cell Deficiency and Functional Impairment in Sleep Apnea: Links to Cancer Comorbidity.

STUDY OBJECTIVES: Emerging evidence links obstructive sleep apnea (OSA) with increased cancer incidence and mortality. Invariant natural killer T (iNKT) cells play an important role in cancer immunity. We hypothesized that patients with OSA have low number of circulating invariant natural killer T (iNKT) cells, which may also be functionally impaired. This study aims to evaluate the frequency of circulating iNKT cells in OSA. DESIGN: We evaluated the frequency of circulating iNKT cells by flow cytometry in 33 snorers being assessed for possible OSA. Using iNKT cell lines, we also evaluated the effect of exposure to hypoxia over 24 hours on apoptosis, cytotoxicity, and cytokine production. SETTING: Teaching hospital based sleep unit and research laboratory. PATIENTS: Thirty-three snorers were evaluated: 9 with no OSA (apnea-hypopnea frequency [AHI] < 5/h), 12 with mild-moderate OSA (AHI 5-30) and 12 with severe OSA (AHI > 30). MEASUREMENTS AND RESULTS: Patients with severe OSA had considerably fewer iNKT cells (0.18%) compared to patients with mild-moderate (0.24%) or no OSA (0.35%), P = 0.0026. The frequency of iNKT cells correlated negatively with apnea-hypopnea index (r = -0.58, P = 0.001), oxygen desaturation index (r = -0.58, P = 0.0003), and SpO2% < 90% (r = -0.5407, P = 0.005). The frequency of iNKT cells increased following 12 months of nCPAP therapy (P = 0.015). Hypoxia resulted in increased apoptosis (P = 0.016) and impaired cytotoxicity (P = 0.035). CONCLUSION: Patients with obstructive sleep apnea (OSA) have significantly reduced levels of circulating invariant natural killer T (iNKT) cells and hypoxia leads to impaired iNKT cell function. These observations may partly explain the increased cancer risk reported in patients with OSA.

Severity of obstructive sleep apnoea predicts coronary artery plaque burden: a coronary computed tomographic angiography study.

Obstructive sleep apnoea (OSA) is associated with significantly increased risk of cardiovascular disease. Carotid ultrasonography and retrospective, uncontrolled, coronary imaging studies have suggested an association of OSA with subclinical atherosclerosis, but there is a lack of prospective, controlled studies directly evaluating the relationship of OSA with occult coronary artery disease. We performed coronary computed tomographic angiography and inpatient-attended sleep studies on a cohort of otherwise healthy males attending our sleep laboratory, and compared coronary artery plaque volume between subjects with low and high apnoea/hypopnoea index (AHI) scores. 29 subjects participated. The median AHI was 15.5 events · h(-1), with subjects who scored above this classified as high AHI. No significant differences were observed in demographic, anthropometric and clinical variables between the high- and low-AHI groups. Coronary plaque volume was significantly greater in the high-AHI group (mean plaque volume 2.6 ± 0.7 mm(2) versus 0.8 ± 0.2 mm(2); p=0.017) and, furthermore, correlated significantly with AHI (Spearman's r=0.433; p=0.019). Following adjustment for dyslipidaemia and fasting plasma glucose levels, AHI remained a significant predictor of plaque volume (standardised ß=0.424; p=0.027). In this prospective case-control study, we found that severity of OSA may predict occult coronary atherosclerosis in otherwise healthy overweight or obese male subjects.

Weight Care Project: Health professionals' attitudes and ability to assess body weight status - study protocol.

BACKGROUND: Health professionals working in primary care and public health have opportunities to address body weight status issues with their patients through face-to-face contact. The objectives of this all-Ireland project are: 1. to assess the attitudes, current practices/behaviours and knowledge of key health professional groups on body weight status; 2. to assess the health professional groups' ability to identify body weight status in both adults and children. The health professional groups are: (a) community related public health nurses; (b) school public health nurses; (c) GPs and practice nurses (primary care); and (d) occupational health nurses (workplace) from both Northern Ireland and the Republic of Ireland. METHODS/DESIGN: This all-Ireland multi-disciplinary project follows a mixed methods approach using both quantitative and qualitative methodologies, and consists of four components:1. Literature review - to explore the role of health professionals in managing obesity through spontaneous intervention in a variety of health promotion settings.2. Telephone interviews and focus groups - to gain an in-depth insight into the views of health professionals in assessing body weight status.3. Survey (primarily online but also paper-based) - to determine the attitudes, current practices/behaviours and knowledge of health professionals in assessing body weight status.4. Online evaluation study - an online interactive programme will be developed to assess health professionals' ability to identify the body weight status of adults and children. DISCUSSION: This project will assess and report the attitudes, current practices/behaviours and knowledge of key health professional groups within Northern Ireland and the Republic of Ireland on body weight status, and their ability to identify body weight status in both adults and children. The results of this project will generate recommendations for clinical practice in managing obesity, which may inform policy guidelines.

Effects of salmeterol on sleeping oxygen saturation in chronic obstructive pulmonary disease.

BACKGROUND: Sleep is associated with important adverse effects in patients with chronic obstructive pulmonary disease (COPD), such as disturbed sleep quality and gas exchange, including hypoxemia and hypercapnia. The effects of inhaled long-acting beta(2)-agonist therapy (LABA) on these disturbances are unclear. OBJECTIVES: The aim of the study was to assess the effect of inhaled salmeterol on nocturnal sleeping arterial oxygen saturation (SaO(2)) and sleep quality. METHODS: In a randomized, double-blind, placebo-controlled, crossover study of moderate/severe stable COPD patients, we compared the effects of 4 weeks of treatment with salmeterol 50 microg b.d. and matching placebo on sleeping SaO(2) and sleep quality. Overnight polysomnography (PSG) was performed at baseline, and after 4 and 8 weeks in addition to detailed pulmonary function testing. Of 15 patients included, 12 completed the trial (median age 69 years, forced expiratory volume in 1 s, FEV(1): 39%). RESULTS: Both mean SaO(2) [salmeterol vs. placebo: 92.9% (91.2, 94.7) vs. 91.0% (88.9, 94.8); p = 0.016] and the percentage of sleep spent below 90% of SaO(2) [1.8% (0.0, 10.8) vs. 25.6% (0.5, 53.5); p = 0.005] improved significantly with salmeterol. Sleep quality was similar with both salmeterol and placebo on PSG. Static lung volumes, particularly trapped gas volume, tended to improve with salmeterol. CONCLUSION: We conclude that inhaled LABA therapy improves sleeping SaO(2) without significant change in sleep quality.

Effects of heated humidification and topical steroids on compliance, nasal symptoms, and quality of life in patients with obstructive sleep apnea syndrome using nasal continuous positive airway pressure.

BACKGROUND: Nasal side effects are common in patients with obstructive sleep apnea syndrome (OSAS) starting on nasal continuous positive airway pressure (CPAP) therapy. We tested the hypothesis that heated humidification or nasal topical steroids improve compliance, nasal side effects and quality of life in this patient group. METHODS: 125 patients with the established diagnosis of OSAS (apnea/hypopnea index > or = 10/h), who tolerated CPAP via a nasal mask, and who had a successful CPAP titration were randomized to 4 weeks of dry CPAP, humidified CPAP or CPAP with additional topical nasal steroid application (fluticasone, GlaxoWellcome). Groups were similar in all demographic variables and in frequency of nasal symptoms at baseline. Outcome measures were objective compliance, quality of life (short form 36), subjective sleepiness (Epworth Sleepiness Scale score) and nasal symptoms such as runny, dry or blocked nose, sneezing and headaches; all variables assessed using a validated questionnaire and by direct interview. RESULTS: There was no difference in compliance between groups after 4 weeks (dry: 5.21 +/- 1.66 h/night, fluticasone: 5.66 +/- 1.68, humidifier: 5.21 +/- 1.84; p = 0.444). Quality of life and subjective sleepiness improved in all groups, but there were no differences in the extent of improvement. Nasal Symptoms were less frequently reported in the humidifier group (28%) than in the remaining groups (dry: 70%, fluticasone: 53%, p = 0.002). However, the addition of fluticasone resulted in increased frequency of sneezing. CONCLUSION: The addition of a humidifier, but not nasal steroids decreases the frequency of nasal symptoms in unselected OSAS patients initiating CPAP therapy; however compliance and quality of life remain unaltered.

Auto-adjusting versus fixed positive pressure therapy in mild to moderate obstructive sleep apnoea.

STUDY OBJECTIVES: To determine if auto-adjusting positive airway pressure (APAP) would be better tolerated on the basis of delivering a lower mean pressure in patients with mild to moderate obstructive sleep apnoea syndrome (OSAS). DESIGN: Patients spent 8 weeks on continuous positive airway pressure (CPAP) and 8 weeks on APAP in a randomized crossover design. SETTING: Respiratory Sleep Disorders Unit in a University Hospital and the patient's home. PARTICIPANTS: Twenty-nine patients with newly diagnosed mild to moderate OSAS (apnoea-hypopnoea frequency of 5-30 events/hour) were studied. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Overnight polysomnography and Epworth Sleepiness Scale were recorded at baseline and at the end of each treatment period in addition to patient preference for device, side effects, and objective compliance. No differences were found in polysomnographic variables or Epworth Sleepiness Scale scores between the 2 treatment modes, but all variables were significantly improved from baseline values. Mean APAP pressure levels were significantly lower than CPAP (6.3 +/- 1.4 vs 8.1 +/- 1.7 cm H2O, p < .001). Patient compliance was similar with both treatments. More patients requiring higher fixed pressure (> or = 8cm H2O) preferred APAP, whereas those requiring lower pressure (< 8 cm H2O) preferred CPAP (p = .03). Follow-up after 18 months of therapy indicated that 76% of subjects continued to be compliant, with a nightly use of 5.8 +/- 1.9 hours per night, despite high levels of minor side effects. CONCLUSIONS: APAP and CPAP are equally effective in managing patients with mild to moderate OSAS, but device preference may be influenced by fixed pressure requirements.

Cardiovascular risk markers in obstructive sleep apnoea syndrome and correlation with obesity.

BACKGROUND: High C-reactive protein (CRP) and homocysteine levels are risk factors for cardiovascular disease. Some, but not all, previous studies have reported increased levels of CRP and homocysteine in patients with obstructive sleep apnoea syndrome (OSAS). A study was undertaken to investigate the levels of these factors in carefully selected patients with OSAS and matched normal controls. METHODS: CRP and homocysteine levels were measured in 110 subjects following polysomnography (PSG). Non-OSAS patients (group 1) were compared with two patient groups (mild/moderate OSAS (group 2) and severe OSAS (group 3)) group-matched for body mass index (BMI), and a fourth group of patients with severe OSAS who were more obese (group 4). All were free of other disease and similar in age, smoking habits and cholesterol levels. 50 suitable patients were commenced on continuous positive airway pressure (CPAP) treatment after PSG and 49 were reassessed 6 weeks later. RESULTS: CRP levels were similar in groups 1, 2 and 3 (median (interquartile range (IQR)) 1.11 (0.76-2.11) mg/l vs 1.82 (1.20-3.71) mg/l vs 2.20 (1.16-3.59) mg/l; p=0.727, Kruskal-Wallis test), but were significantly higher in group 4 than in the other groups (5.36 (2.42-9.17) mg/l, p<0.05 by individual group comparisons). In multivariate analysis of all subjects, BMI was an independent predictor for CRP levels (beta=0.221; p=0.006) but apnoea-hypopnoea index and other measures of OSAS were not. There was no difference in homocysteine levels between all four groups (p=0.1). CPAP did not alter CRP (2.29 (1.32-4.10) vs 2.84 (1.13-5.40) mg/l; p=0.145) or homocysteine levels (8.49 (3.66) vs 9.90 (4.72) micromol/l; p=0.381). CONCLUSION: CRP and homocysteine levels are not associated with OSAS severity in men but CRP is independently associated with obesity.

Hurling alone? How social capital failed to save the Irish from cardiovascular disease in the United States.

OBJECTIVES: We performed a historical review of cardiovascular risk profiles of Irish immigrants to the United States, 1850-1970, in regard to lifestyle, socio-economic circumstances, and social capital. METHODS: We analyzed US Census data from 1850-1970, area-based social and epidemiological data from Boston, data from Ireland's National Nutrition Surveillance Centre, and literature on Irish migration. RESULTS: The Irish were consistently at increased risk of cardiovascular diseases, a risk that related initially to material deprivation, across the life course of at least 2 generations. CONCLUSIONS: The principal difference between the Irish and other disadvantaged immigrant groups, such as the Italians, was dietary habits influenced by experiences during the Irish famine. Although there was a psychosocial component to the disadvantage and discrimination they experienced as an ethnic group, the Irish also exhibited strong community networks and support structures that might have been expected to counteract discrimination's negative effects. However, the Irish's high levels of social capital were not protective for cardiovascular disease.

Dieting patterns and related lifestyles of school-aged children in the Republic of Ireland.

OBJECTIVE: The aim of this study was to identify differences in food habits and lifestyle behaviours by dieting status among young people in Ireland. DESIGN: Cross-sectional survey. Participants responded to a self-completion questionnaire designed by researchers on the World Health Organization's collaborative study - Health Behaviour in School Aged Children. Pupils were selected by school and classroom and the sample was stratified to be representative of the geographical distribution of school students in Ireland. SETTING: Data were collected by teachers from school pupils in their classrooms. SUBJECTS: Data were collected from 187 schools which included 8497 pupils (51% girls) aged 9-17 years. RESULTS: While a minority of pupils (12% of girls, 4% of boys) reported that they were on a diet to lose weight, a substantial proportion (28% of girls, 18% of boys) said that they should be on a diet. Dieters reported consuming unhealthy foods less frequently than non-dieters, but did not report an increased consumption of fruit and vegetables. Rather, some categories of dieters reported higher levels of coffee and tobacco use and lower exercise levels than non-dieters. CONCLUSIONS: The results could indicate substitution of unhealthy foods by other unhealthy behaviours as opposed to an increased consumption of healthier foodstuffs, and suggest that both smoking and exercise need to be addressed alongside nutrition in youth health promotion.

Effect of social variation on the Irish diet.

Both jurisdictions of Ireland have high rates of chronic degenerative diseases, particularly of the cardiovascular system, and Irish migrants have worse health profiles, often lasting at least two generations. The influence of socio-demographic variation over the life course, and what role diet plays, has not been well researched in epidemiological terms. There is a long history of an unusual Irish diet. Estimated dietary fat intake (% total energy intake) in 1863 was only 9, but had reached 30 in 1948 and 34 in 1999. Conversely, carbohydrate intake has fallen steadily over 150 years. From 1948 onwards household budget survey data illustrate patterns of increasing urbanisation and socio-economic gradients in food availability. The National Survey of Lifestyles, Attitudes and Nutrition, (n 6539, 62.2% response rate) provides clear evidence of inverse social-class gradients in intake of fruit and vegetables and dairy products and in reported patterns of healthy eating. Median carbohydrate and vitamin C levels are higher among social classes 1-2 and mean saturated fat intake is lower. International comparisons indicate a continuing, if narrowing, north-south gradient across Europe. Data from the Boston-Ireland study suggest a crossover in both dietary intake patterns and risk of heart disease in Ireland and the USA in the 1970s. Contemporary comparative data of middle-aged Irish and American women demonstrate patterns of diet intake and inactivity consistent with the modern epidemic of obesity and non-insulin-dependent diabetes. Thus, dietary variations within and between countries and over time are consistent with chronic disease patterns in contemporary Ireland.