Nocturnal gastro-oesophageal reflux and respiratory symptoms are increased in sleep apnoea: comparison with the general population.

AIM: To assess respiratory symptoms and nocturnal gastro-oesophageal reflux (nGER) among untreated obstructive sleep apnoea (OSA) patients, compared with the general population. Also, if nGER associates differently with respiratory symptoms among OSA patients. METHODS: 2 study cohorts were included: 822 newly diagnosed subjects with moderate-severe OSA and 738 Icelandic general population study participants. All participants answered the same questionnaires. Those reporting nGER symptoms at least once per week were defined as 'with nGER'; those without nGER symptoms and without nGER medication were defined as 'no nGER'; and other participants were defined as having 'possible nGER'. Propensity score-based weights were used to minimise confounding and selection bias and facilitate causal interpretations. RESULTS: The prevalence of nGER among OSA patients was 14.1%, compared with 5.8% in the general population. This increased prevalence in OSA was not explained by differences in age, gender, body mass index, smoking, hypertension and diabetes (adjusted OR (95% CI)=3.79 (2.24 to 6.43)). OSA patients 'with nGER' and with 'possible nGER' reported more wheezing (44% and 44% vs 25%, respectively) and productive cough (47% and 42% vs 29%, respectively), compared with OSA patients with 'no nGER'. The same pattern was seen in the general population, although with a generally lower prevalence. The effect of nGER on respiratory symptoms was similar between the two cohorts. CONCLUSION: nGER was more often reported among untreated moderate-severe OSA patients than in the general population. Participants with nGER had more wheezing and productive cough, both among untreated OSA patients and in the general population.

Positive airway pressure treatment affects respiratory symptoms and gastro-oesophageal reflux: the Icelandic Sleep Apnea Cohort Study.

Aim: To study the effect of positive airway pressure (PAP) treatment on nocturnal gastro-oesophageal reflux (nGOR) and respiratory symptoms among clinical obstructive sleep apnoea (OSA) patients. Methods: 822 patients newly diagnosed with OSA referred for PAP treatment were recruited. 732 patients had a 2-year follow-up visit with continuous PAP compliance data (366 full PAP users, 366 partial/non-PAP users). They answered questionnaires, including reporting of nGOR, sleep and respiratory symptoms and general health. Patients with nGOR symptoms once a week or more were defined as "with nGOR". Those without nGOR symptoms and nGOR medication were defined as "no nGOR". Others were defined as "possible nGOR". Results: At 2-year follow-up, PAP treatment among full users resulted in decreased nGOR (adjusted OR 0.58, 95% CI 0.40-0.86) and wheezing (adjusted OR 0.56, 95% CI 0.35-0.88) compared with partial/non-PAP users. Decreased nGOR, among both full and partial/non-users of PAP treatment, was associated with a decrease in productive morning cough (adjusted OR 4.70, 95% CI 2.22-9.99) and a decrease in chronic bronchitis (adjusted OR 3.86, 95% CI 1.74-8.58), but not decreased wheezing (adjusted OR 0.90, 95% CI 0.39-2.08). A mediation analysis found that PAP treatment directly led to a decrease in wheezing, not mediated through nGOR. Conversely, PAP treatment decreased productive cough mediated through a decrease in nGOR. Conclusion: In an unselected group of OSA patients, PAP treatment for 2 years was associated with a decrease in nGOR and respiratory symptoms. The PAP treatment itself was associated with less wheezing. A decrease in nGOR through PAP treatment was associated with a decrease in productive cough.

Different components of excessive daytime sleepiness and the change with positive airway pressure treatment in patients with obstructive sleep apnea: Results from the Icelandic Sleep Apnea Cohort (ISAC).

Excessive daytime sleepiness includes both an inability to stay awake during the day and a general feeling of sleepiness. We describe different dimensions of daytime sleepiness in adults with moderate-severe obstructive sleep apnea (OSA) before and after 2 years of positive airway pressure (PAP) treatment. Using the Epworth Sleepiness Scale (score >10 defined as "risk of dozing") and Basic Nordic Sleep Questionnaire (feeling sleepy ≥3 times/week defined as "feeling sleepy"), participants were categorised into sleepiness phenotypes labelled non-sleepy, risk of dozing only, feeling sleepy only, or both symptoms. Participants repeated baseline assessments and PAP adherence was evaluated after 2 years. PAP-adherent subjects with sleepiness symptoms at both baseline and follow-up were considered persistently sleepy. Of the 810 participants, 722 (89%) returned for follow-up. At baseline, 17.7% were non-sleepy, 7.7% were at risk of dozing only, 24.7% were feeling sleepy only, and 49.9% had both symptoms. PAP adherence did not differ by baseline sleepiness phenotype. Patients with risk of dozing demonstrated greater PAP benefits for sleepiness symptoms than non-sleepy and feeling sleepy only phenotypes. Using these phenotypes, 42.3% of PAP users had persistent sleepiness; they had less severe OSA (p < 0.001), more persistent OSA symptoms and more often had symptoms of insomnia than patients in whom sleepiness resolved. Our present results, therefore, suggest that measuring the risk of dozing and the feeling of sleepiness reflect different sleepiness components and may respond differently to PAP. Patients feeling sleepy without risk of dozing may need more thorough evaluation for factors contributing to sleepiness before initiating treatment.

Differences in three-dimensional upper airway anatomy between Asian and European patients with obstructive sleep apnea.

STUDY OBJECTIVES: This study evaluated differences in upper airway, soft tissues and craniofacial structures between Asians from China and Europeans from Iceland with OSA using three-dimensional magnetic resonance imaging (MRI). METHODS: Airway sizes, soft tissue volumes, and craniofacial dimensions were compared between Icelandic (N = 108) and Chinese (N = 57) patients with oxygen desaturation index (ODI) ≥ 10 events/h matched for age, gender, and ODI. Mixed effects models adjusting for height or BMI and residual differences in age and ODI were utilized. RESULTS: In our matched sample, compared to Icelandic OSA patients, Chinese patients had smaller BMI (p < 0.0001) and neck circumference (p = 0.011). In covariate adjusted analyses, Chinese showed smaller retropalatal airway size (p ≤ 0.002), and smaller combined soft tissues, tongue, fat pads, and pterygoid (all p ≤ 0.0001), but male Chinese demonstrated a larger soft palate volume (p ≤ 0.001). For craniofacial dimensions, Chinese demonstrated bigger ANB angle (p ≤ 0.0196), differently shaped mandibles, including shorter corpus length (p < 0.0001) but longer ramus length (p < 0.0001), and a wider (p < 0.0001) and shallower (p ≤ 0.0001) maxilla. CONCLUSIONS: Compared to Icelandic patients of similar age, gender and ODI, Chinese patients had smaller retropalatal airway and combined soft tissue, but bigger soft palate volume (in males), and differently shaped mandible and maxilla with more bony restrictions. Results support an ethnic difference in upper airway anatomy related to OSA, which may inform targeted therapies.

PAP treatment in patients with OSA does not induce long-term nasal obstruction.

We hypothesized that positive airway pressure treatment would induce nasal obstruction and decrease nasal cavity due to mucosal swelling. We further hypothesized that subjective and objective nasal obstruction at baseline would negatively affect positive airway pressure adherence. A total of 728 patients with sleep apnea were investigated in the Icelandic Sleep Apnea Cohort at baseline and 2 years after starting positive airway pressure. Patients underwent home sleep apnea testing at baseline. Questionnaires were answered and acoustic rhinometry was completed at baseline and follow-up. The proportion of patients reporting subjective nocturnal nasal obstruction was reduced (baseline: 35% versus follow-up: 24%; p < 0.001). Small interior nasal dimensions increased (p < 0.001) independent of adherence to treatment. Small nasal volume at baseline was a determinant for becoming a non-user of positive airway pressure treatment (odds ratio 2.22, confidence interval 95% 1.35-3.67, p = 0.002). Subjective nasal obstruction decreased 2 years after initiating positive airway treatment in sleep apnea, and objectively small nasal dimensions increased. Small nasal volume at baseline was a negative predictor for positive airway pressure treatment adherence. Maybe most importantly, positive airway pressure treatment did not cause long-term objective or subjective nasal obstruction.

Lifetime alcohol intake and pattern of alcohol consumption in patients with alcohol-induced pancreatitis in comparison with patients with alcohol use disorder.

OBJECTIVE: To examine lifetime drinking patterns in men and women with alcohol-induced pancreatitis (AIP) in comparison with patients with alcoholic use disorder (AUD) without pancreatic disease. METHODS: Alcohol consumption patterns were assessed using a validated questionnaire, the Lifetime Drinking History (LDH), during an outpatient visit. Patients diagnosed with AIP were matched for gender and age (+/- 5 years) with patients with AUD in addiction treatment. RESULTS: A total of 45 patients with AIP (35 males, 10 females) and 45 AUD patients were included. Alcohol consumption patterns were not significantly different between males and females with AIP and those with history of acute AIP and chronic pancreatitis (CP). Alcohol consumption patterns of AIP and AUD patients were similar in terms of onset age and duration of alcohol consumption, lifetime alcohol intake and drinks per drinking day. A higher proportion of binge drinking was found among patients with AUD than those with AIP (median 1.00 vs. 0.94, p = .01). Males with AUD had lower onset age (15 vs. 16 years, p = .03), higher total amount of spirits (35520 vs. 10450 drinks, p = .04) and higher proportion of binge drinking (1.00 vs. 0.97, p = .01) than males with AIP, whereas females with AIP and AUD had similar drinking patterns. CONCLUSIONS: Alcohol drinking patterns and lifetime drinking history was similar in patients with AIP and patients with AUD. Males with AIP had lower total amount of spirits and lower proportion of binge drinking than those with AUD, suggesting the idiosyncratic etiology of AIP.

Nocturnal nasal obstruction is frequent and reduces sleep quality in patients with obstructive sleep apnea.

The prevalence and consequences of nasal obstruction in untreated obstructive sleep apnea patients are not known. The study objectives were to investigate the frequency of subjective and objective nasal obstruction in untreated sleep apnea patients and the associations with sleep and quality of life. Patients in the Icelandic Sleep Apnea Cohort were subjected to a type 3 sleep study, answered questionnaires and had their nasal dimensions measured by acoustic rhinometry. In total, 810 patients participated (including 153 females), aged 54.5 ± 10.6 years [mean ± standard deviation (SD)] with an apnea/hypopnea index 44.7 ± 20.7 h-1 . Nocturnal nasal obstruction (greater than or equal to three times per week) was reported by 35% of the patients. These patients had smaller nasal dimensions measured by the minimum cross-sectional area within the smaller nasal valve (0.42 ± 0.17 versus 0.45 ± 0.16 cm2 , P = 0.013), reported more daytime sleepiness (Epworth Sleepiness Scale score 12.5 ± 4.9 versus 10.8 ± 5.0; P < 0.001) and slightly lower mental quality of life than patients without nocturnal nasal obstruction. Nocturnal nasal obstruction is reported in one-third of the sleep apnea patients and they are more likely to suffer from daytime sleepiness and slightly reduced quality of life than other sleep apnea patients.

Respiratory symptoms, sleep-disordered breathing and biomarkers in nocturnal gastroesophageal reflux.

BACKGROUND: Nocturnal gastroesophageal reflux (nGER) is associated with respiratory symptoms and sleep-disordered breathing (SDB), but the pathogenesis is unclear. We aimed to investigate the association between nGER and respiratory symptoms, exacerbations of respiratory symptoms, SDB and airway inflammation. METHODS: Participants in the European Community Respiratory Health Survey III in Iceland with nGER symptoms (n = 48) and age and gender matched controls (n = 42) were studied by questionnaires, exhaled breath condensate (EBC), particles in exhaled air (PEx) measurements, and a home polygraphic study. An exacerbation of respiratory symptoms was defined as an episode of markedly worse respiratory symptoms in the previous 12 months. RESULTS: Asthma and bronchitis symptoms were more common among nGER subjects than controls (54 % vs 29 %, p = 0.01; and 60 % vs 26 %, p < 0.01, respectively), as were exacerbations of respiratory symptoms (19 % vs 5 %, p = 0.04). Objectively measured snoring was more common among subjects with nGER than controls (snores per hour of sleep, median (IQR): 177 (79-281) vs 67 (32-182), p = 0.004). Pepsin (2.5 ng/ml (0.8-5.8) vs 0.8 ng/ml (0.8-3.6), p = 0.03), substance P (741 pg/ml (626-821) vs 623 pg/ml (562-676), p < 0.001) and 8-isoprostane (3.0 pg/ml (2.7-3.9) vs 2.6 pg/ml (2.2-2.9), p = 0.002) in EBC were higher among nGER subjects than controls. Albumin and surfactant protein A in PEx were lower among nGER subjects. These findings were independent of BMI. CONCLUSION: In a general population sample, nGER is associated with symptoms of asthma and bronchitis, as well as exacerbations of respiratory symptoms. Also, nGER is associated with increased respiratory effort during sleep. Biomarker measurements in EBC, PEx and serum indicate that micro-aspiration and neurogenic inflammation are plausible mechanisms.

Definition of nocturnal gastroesophageal reflux for studies on respiratory diseases.

OBJECTIVE: Nocturnal gastroesophageal reflux (nGER) has been associated with respiratory diseases. Our aim was to study a questionnaire method to identify nGER subjects with respiratory involvement in a general population. MATERIAL AND METHODS: A subgroup of Icelandic participants in the European Community Respiratory Health Survey III (ECRHS III) reporting symptoms of nGER (n = 48) as well as age and gender paired controls (n = 42) were studied further by a structured interview, questionnaires, laryngeal fibrescopy, and exhaled breath condensate. A subgroup underwent 24-h oesophageal pH impedance (24-h MII-pH) measurements. Symptoms of nGER were assessed with a modified version of the reflux disease questionnaire (RDQ), where symptoms were divided into daytime and nocturnal. A report of nGER both at baseline and at follow-up was defined as persistent nGER. RESULTS: Participants reporting persistent nGER had significantly more signs of laryngopharyngeal reflux according to the reflux finding score than those without nGER (Mean ± SD: 5.1 ± 2.3 vs. 3.9 ± 2.2, p = 0.02). Of the 16 persistent nGER subjects that underwent 24-h MII-pH, 11 had abnormal gastroesophageal reflux, but none of three control subjects (69% vs. 0%). Pepsin was more commonly found in exhaled breath condensate in the nGER group (67% vs. 45%, p = 0.04). CONCLUSIONS: Participants with nGER symptoms at least once a month, reported on two occasions, had a high level of positive 24-h MII-pH measurements, laryngeal inflammation and pepsin in exhaled breath condensate. This nGER definition identified a representable group for studies on nGER and respiratory diseases in a general population.

Fiix-prothrombin time versus standard prothrombin time for monitoring of warfarin anticoagulation: a single centre, double-blind, randomised, non-inferiority trial.

BACKGROUND: Rapid fluctuations in factor VII during warfarin anticoagulation change the international normalised ratio (INR) but contribute little to the antithrombotic effect. We aimed to assess non-inferiority of anticoagulation stabilisation with a warfarin monitoring method affected only by factors II and X (Fiix-prothrombin time [Fiix-PT]) compared with standard PT-INR monitoring that includes factor VII measurement as well. METHODS: The Fiix trial was a single centre, double-blind, prospective, non-inferiority, randomised controlled clinical trial. Ambulatory adults on warfarin with an INR target of 2-3 managed by an anticoagulation dosing service using software-assisted dosing at the National University Hospital of Iceland, Reykjavik, Iceland, were eligible for inclusion in this study. We excluded patients undergoing electroconversion and nursing home residents. Patients were randomly assigned (1:1) to either the Fiix-PT monitoring group or the PT monitoring group by block randomisation. A blinded research INR (R-INR) based on results of the respective test was reported to the dosing staff. Participants were contacted by a study nurse at 4-week intervals to elicit information about thromboembolism or bleeding otherwise unknown to the anticoagulation management centre. The primary efficacy outcome was a composite of objectively diagnosed non-fatal and fatal arterial or venous thromboembolism, including myocardial infarction and transient ischaemic attacks, assessed in all eligible patients who were randomised (intention-to-monitor population). The safety endpoint was major bleeding or other clinically relevant bleeding, assessed in the per-protocol population. We assumed a 3% annual thromboembolism incidence and a non-inferiority margin of 2·5%. This trial is registered with ClinicalTrials.gov, number NCT01565239. FINDINGS: Between March 1, 2012, and Feb 28, 2014, we enrolled 1156 patients. 573 patients were assigned to Fiix-PT and 575 to PT-INR monitoring after exclusion of four patients from each group for various reasons. Median follow-up was 1·7 years (IQR 1·1-1·9). During days 1-720, ten (1·2% per patient year) thromboembolic events occurred in the Fiix-PT group versus 19 (2·3% per patient year) in the PT group (relative risk [RR] 0·52, 95% CI 0·25-1·13; pnon-inferiority<0·0001). Major bleeding occurred in 17 of 571 patients in the Fiix group (2·2% per patient year) versus 20 of 573 patients in the PT group (2·5% per patient year; RR 0·85, 0·45-1·61; pnon-inferiority=0·0034). Anticoagulation stability was improved with Fiix-PT monitoring as manifested by fewer tests, fewer dose adjustments, increased time in range and less INR variability than reported with standard PT monitoring. INTERPRETATION: Monitoring of warfarin with Fiix-PT improved anticoagulation and dosing stability and was clinically non-inferior to PT monitoring. Results from this trial suggest that during vitamin K antagonist treatment INR monitoring could be replaced by Fiix-PT and that this would lead to at least a non-inferior clinical outcome compared with monitoring with PT-INR. FUNDING: Innovation Center Iceland, University of Iceland Science Fund, Landspitali Science Fund and Actavis.

Effects of obesity on the association between long-term sleep apnea treatment and changes in interleukin-6 levels: the Icelandic Sleep Apnea Cohort.

The aim of this study was to evaluate changes in interleukin (IL)-6 and soluble IL-6 receptor levels in obstructive sleep apnea patients and assess the role of positive airway pressure treatment and obesity on these changes. A total of 309 newly diagnosed subjects with sleep apnea from the Icelandic Sleep Apnea Cohort were referred for treatment and reassessed at a 2-year follow-up. Full treatment was defined objectively as use ≥ 4 h day(-1) and ≥ 20 days month(-1). At the 2-year follow-up, there were 177 full users, 44 partial users and 88 non-users. The mean change in biomarker levels from baseline to the 2-year follow-up was assessed in a primary model that included adjustment for baseline biomarker levels, baseline body mass index and change in body mass index, as well as after adjustment for numerous relevant covariates. No significant overall difference in IL-6 level change was found among full, partial and non-users. However, in severely obese patients (body mass index ≥ 35), a significant increase in IL-6 levels during the 2-year period was found in partial and non-users, compared to no change in full users. Results were attenuated in a smaller propensity score matched subsample, although similar trends were observed. No differences were found in soluble IL-6 receptor levels between full users and non-users, after adjustment for confounders. In conclusion, among untreated obese sleep apnea patients, IL-6 levels increase substantially during 2 years, while adherence to positive airway pressure treatment may prevent further increases in this inflammatory biomarker.

Obstructive sleep apnoea treatment and fasting lipids: a comparative effectiveness study.

Obstructive sleep apnoea (OSA) is associated with cardiovascular disease. Dyslipidaemia has been implicated as a mechanism linking OSA with atherosclerosis, but no consistent associations with lipids exist for OSA or positive airway pressure treatment. We assessed the relationships between fasting lipid levels and obesity and OSA severity, and explored the impact of positive airway pressure treatment on 2-year fasting lipid level changes. Analyses included moderate-to-severe OSA patients from the Icelandic Sleep Apnoea Cohort. Fasting morning lipids were analysed in 613 untreated participants not on lipid-lowering medications at baseline. Patients were then initiated on positive airway pressure and followed for 2 years. Sub-classification using propensity score quintiles, which aimed to replicate covariate balance associated with randomised trials and, therefore, minimise selection bias and allow causal inference, was used to design the treatment group comparisons. 199 positive airway pressure adherent patients and 118 non-users were identified. At baseline, obesity was positively correlated with triglycerides and negatively correlated with total cholesterol, and low-density and high-density lipoprotein cholesterol. A small correlation was observed between the apnoea/hypopnoea index and high-density lipoprotein cholesterol. No effect of positive airway pressure adherence on 2-year fasting lipid changes was observed. Results do not support the concept of changes in fasting lipids as a primary mechanism for the increased risk of atherosclerotic cardiovascular disease in OSA.

Facial phenotyping by quantitative photography reflects craniofacial morphology measured on magnetic resonance imaging in Icelandic sleep apnea patients.

STUDY OBJECTIVES: (1) To determine whether facial phenotype, measured by quantitative photography, relates to underlying craniofacial obstructive sleep apnea (OSA) risk factors, measured with magnetic resonance imaging (MRI); (2) To assess whether these associations are independent of body size and obesity. DESIGN: Cross-sectional cohort. SETTING: Landspitali, The National University Hospital, Iceland. PARTICIPANTS: One hundred forty patients (87.1% male) from the Icelandic Sleep Apnea Cohort who had both calibrated frontal and profile craniofacial photographs and upper airway MRI. Mean ± standard deviation age 56.1 ± 10.4 y, body mass index 33.5 ± 5.05 kg/m(2), with on-average severe OSA (apnea-hypopnea index 45.4 ± 19.7 h(-1)). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Relationships between surface facial dimensions (photos) and facial bony dimensions and upper airway soft-tissue volumes (MRI) was assessed using canonical correlation analysis. Photo and MRI craniofacial datasets related in four significant canonical correlations, primarily driven by measurements of (1) maxillary-mandibular relationship (r = 0.8, P < 0.0001), (2) lower face height (r = 0.76, P < 0.0001), (3) mandibular length (r = 0.67, P < 0.0001), and (4) tongue volume (r = 0.52, P = 0.01). Correlations 1, 2, and 3 were unchanged when controlled for weight and neck and waist circumference. However, tongue volume was no longer significant, suggesting facial dimensions relate to tongue volume as a result of obesity. CONCLUSIONS: Significant associations were found between craniofacial variable sets from facial photography and MRI. This study confirms that facial photographic phenotype reflects underlying aspects of craniofacial skeletal abnormalities associated with OSA. Therefore, facial photographic phenotyping may be a useful tool to assess intermediate phenotypes for OSA, particularly in large-scale studies.

Symptoms of insomnia among patients with obstructive sleep apnea before and after two years of positive airway pressure treatment.

STUDY OBJECTIVES: To assess the changes of insomnia symptoms among patients with obstructive sleep apnea (OSA) from starting treatment with positive airway pressure (PAP) to a 2-y follow-up. DESIGN: Longitudinal cohort study. SETTING: Landspitali--The National University Hospital of Iceland. PARTICIPANTS: There were 705 adults with OSA who were assessed prior to and 2 y after starting PAP treatment. INTERVENTION: PAP treatment for OSA. MEASUREMENTS AND RESULTS: All patients underwent a medical examination along with a type 3 sleep study and answered questionnaires on health and sleep before and 2 y after starting PAP treatment. The change in prevalence of insomnia symptoms by subtype was assessed by questionnaire and compared between individuals who were using or not using PAP at follow-up. Symptoms of middle insomnia were most common at baseline and improved significantly among patients using PAP (from 59.4% to 30.7%, P < 0.001). Symptoms of initial insomnia tended to persist regardless of PAP treatment, and symptoms of late insomnia were more likely to improve among patients not using PAP. Patients with symptoms of initial and late insomnia at baseline were less likely to adhere to PAP (odds ratio [OR] 0.56, P = 0.007, and OR 0.53, P < 0.001, respectively). CONCLUSION: Positive airway pressure treatment significantly reduced symptoms of middle insomnia. Symptoms of initial and late insomnia, however, tended to persist regardless of positive airway pressure treatment and had a negative effect on adherence. Targeted treatment for insomnia may be beneficial for patients with obstructive sleep apnea comorbid with insomnia and has the potential to positively affect adherence to positive airway pressure.

Nocturnal sweating--a common symptom of obstructive sleep apnoea: the Icelandic sleep apnoea cohort.

OBJECTIVES: To estimate the prevalence and characteristics of frequent nocturnal sweating in obstructive sleep apnoea (OSA) patients compared with the general population and evaluate the possible changes with positive airway pressure (PAP) treatment. Nocturnal sweating can be very bothersome to the patient and bed partner. DESIGN: Case-control and longitudinal cohort study. SETTING: Landspitali-The National University Hospital, Iceland. PARTICIPANTS: The Icelandic Sleep Apnea Cohort consisted of 822 untreated patients with OSA, referred for treatment with PAP. Of these, 700 patients were also assessed at a 2-year follow-up. The control group consisted of 703 randomly selected subjects from the general population. INTERVENTION: PAP therapy in the OSA cohort. MAIN OUTCOME MEASURES: Subjective reporting of nocturnal sweating on a frequency scale of 1-5: (1) never or very seldom, (2) less than once a week, (3) once to twice a week, (4) 3-5 times a week and (5) every night or almost every night. Full PAP treatment was defined objectively as the use for ≥4 h/day and ≥5 days/week. RESULTS: Frequent nocturnal sweating (≥3× a week) was reported by 30.6% of male and 33.3% of female OSA patients compared with 9.3% of men and 12.4% of women in the general population (p<0.001). This difference remained significant after adjustment for demographic factors. Nocturnal sweating was related to younger age, cardiovascular disease, hypertension, sleepiness and insomnia symptoms. The prevalence of frequent nocturnal sweating decreased with full PAP treatment (from 33.2% to 11.5%, p<0.003 compared with the change in non-users). CONCLUSIONS: The prevalence of frequent nocturnal sweating was threefold higher in untreated OSA patients than in the general population and decreased to general population levels with successful PAP therapy. Practitioners should consider the possibility of OSA in their patients who complain of nocturnal sweating.

The interaction of obstructive sleep apnea and obesity on the inflammatory markers C-reactive protein and interleukin-6: the Icelandic Sleep Apnea Cohort.

STUDY OBJECTIVES: To assess the relative roles and interaction of obstructive sleep apnea (OSA) severity and obesity on interleukin-6 (IL-6) and C-reactive protein (CRP) levels. DESIGN: Cross-sectional cohort. SETTING: The Icelandic Sleep Apnea Cohort. PARTICIPANTS: 454 untreated OSA patients (380 males and 74 females), mean ± standard deviation age 54.4 ± 10.6 yr. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Participants underwent a sleep study, abdominal magnetic resonance imaging to measure total abdominal and visceral fat volume, and had fasting morning IL-6 and CRP levels measured in serum. A significantly higher correlation was found for BMI than visceral fat volume with CRP and IL-6 levels. Oxygen desaturation index, hypoxia time, and minimum oxygen saturation (SaO2) significantly correlated with IL-6 and CRP levels, but apnea-hypopnea index did not. When stratified by body mass index (BMI) category, OSA severity was associated with IL-6 levels in obese participants only (BMI > 30 kg/m²). A multiple linear regression model with interaction terms showed an independent association of OSA severity with IL-6 levels and an interaction between OSA severity and BMI, i.e., degree of obesity altered the relationship between OSA and IL-6 levels. An independent association of OSA severity with CRP levels was found for minimum SaO2 only. A similar interaction of OSA severity and BMI on CRP levels was found for males and postmenopausal women. CONCLUSIONS: OSA severity is an independent predictor of levels of IL-6 and CRP but interacts with obesity such that this association is found only in obese patients.

Single slice vs. volumetric MR assessment of visceral adipose tissue: reliability and validity among the overweight and obese.

Visceral adipose tissue (VAT) is associated with abnormal cardiovascular and metabolic profiles. Total VAT volume of the abdominal compartment by magnetic resonance imaging (MRI) is the gold-standard measurement for VAT but is costly and time consuming. Prior studies suggest VAT area on a single slice MR image may serve as a surrogate for total VAT volume but it is unknown if this relationship is maintained in overweight and obese men and women. Untreated sleep apnea subjects enrolled into the Icelandic Sleep Apnea Cohort (ISAC) underwent abdominal MRI. VAT area and subcutaneous adipose tissue (SAT) area at the L2-L3 and L4-L5 interspaces and total VAT and SAT volumes were determined by manual examination using image analysis software; 539 men and 129 women with mean ages of 54.1 and 58.8 years and mean BMI of 32.2 kg/m(2) and 33.7 kg/m(2), respectively, were studied. Mean total VAT volume was 40% smaller and mean total SAT was 25% larger among females compared with males. The correlation with VAT volume was significantly larger for L2-L3 VAT area (r = 0.96) compared to L4-L5 VAT area (r = 0.83). The difference in correlation coefficients was statistically significant (nonparametric bootstrap P < 0.001 with 95% confidence interval (CI) for the difference from 0.11 to 0.15. VAT area at L2-L3 was also significantly better correlated with VAT volume than traditional anthropometric variables. Linear regression analyses demonstrated that L2-L3 area alone was sufficient for predicting total VAT volume and that the nature of the linear association was maintained across all levels of obesity and in both genders.

Nocturnal gastroesophageal reflux, lung function and symptoms of obstructive sleep apnea: Results from an epidemiological survey.

BACKGROUND: Nocturnal gastroesophageal reflux (nGER) has received increasing interest as a predisposing factor for respiratory diseases and sleep disturbances. The possible role of obstructive sleep apnea (OSA) contributing to nGER is of special interest. The aim of this study was to explore the association between nGER and respiratory diseases, lung function and symptoms of OSA. METHODS: Participants in the Burden of Obstructive Lung Disease (BOLD) initiative in Iceland and Sweden, a random sample from the general population of 1325 adults aged 40+ (>70% response rate), were compared by pre- and post-bronchodilator spirometry, answers to questionnaires about OSA and respiratory symptoms, health, and symptoms of GER. RESULTS: Altogether 102 (7.7%) reported nGER and 249 had used medication against GER. The participants were divided into three groups: 1) No nGER (n = 1040), 2) treated GER without nGER (n = 183) and 3) nGER (n = 102). The nGER group had a significantly higher prevalence of respiratory and OSA symptoms than subjects without nGER. The nGER group also had a higher prevalence of COPD (GOLD stage 1+), (25.0% vs. 15.6%) (p = 0.02) and lower FEV(1)/FVC ratio (95.9% vs. 98.9% of the predicted, p = 0.01). These associations remained significant after adjusting for smoking, weight and other possible confounders. No independent association was found between having treated GER and lung function, respiratory or OSA symptoms. CONCLUSIONS: In our cross-sectional epidemiological study, untreated nGER is strongly associated with both respiratory and OSA symptoms as well as airflow obstruction.

The effect of reducing levels of cat allergen (Fel d 1) on clinical symptoms in patients with cat allergy.

BACKGROUND: Treatment of cat allergy normally entails removal of the cat from the household, but cat owners are often unwilling to part with their pets, despite clinically relevant allergies. OBJECTIVE: To determine whether levels of Fel d 1 can be reduced without removal of the cat and whether this will affect symptoms of cat allergy. METHODS: Cat-allergic patients underwent randomization to either a group instructed in environmental control (EC) and a group with unchanged environment (UE). Dust samples were obtained and settled Fel d 1 measured by enzyme-linked immunosorbent assay. Patients recorded daily nasal inspiratory flow rates. At baseline, 3 months, and 8 months, patients underwent symptom evaluation. RESULTS: Eighteen patients were randomized to the EC group and 22 to the UE group; the final number completing the study was 31, 15 in the EC group, and 16 in the UE group. At 8 months, home Fel d 1 levels had diminished to 6.8% of baseline levels in the EC group, whereas no reduction in levels was noted in the UE group. In the EC group, significant improvements were found in nasal inspiratory flow rate and symptoms compared with the UE group. Patients did not have difficulties adhering to EC measures. CONCLUSION: A decrease in the allergen load was found in the EC group, which had a significant effect on symptoms of nasal allergy.