The association between circulating adiponectin levels, lung function and adiposity in subjects from the general population; data from the Akershus Sleep Apnea Project.

BACKGROUND: Circulating adiponectin (ADPN) levels are inversely associated with disease severity in patients with chronic obstructive pulmonary disease (COPD), while studies assessing the relationship between ADPN and lung function in subjects from the general population have shown diverging results. Accordingly, we hypothesized that ADPN would be associated with lung function in a population-based sample and tested how abdominal adiposity, metabolic syndrome, and systemic inflammation influenced this association. METHODS: We measured total ADPN in serum, forced vital capacity (FVC) and forced expiratory volume during the 1st second (FEV1) in 529 participants (median 50 years, 54.6% males) recruited from the general population. We assessed the association between ADPN and lung function by multivariate linear regression analyses and adjusted for age, gender, height, smoking habits, weight, body mass index, waist-hip ratio, metabolic syndrome, obstructive sleep apnoea (OSA) and C-reactive protein. RESULTS: The median (interquartile range) level of serum ADPN was 7.6 (5.4-10.4) mg/L. ADPN levels were positively associated with FVC % of predicted (beta 3.4 per SD adiponectin, p < 0.001)) in univariate linear regression analysis, but the association was attenuated in multivariate analysis (standardized beta 0.03, p = 0.573)). Among co-variates only WHR significantly attenuated the relationship. ADPN levels were also associated with FEV1% of predicted in bivariate analysis that adjusted for smoking (beta 1.4, p = 0.042)), but this association was attenuated and no longer significant in multivariate analysis (standardized beta -0.06, p = 0.254)). CONCLUSION: In this population-based sample no association between ADPN and lung function was evident after adjustment for covariates related to adiposity.

Biomarkers of cardiovascular injury and stress are associated with increased frequency of ventricular ectopy: a population-based study.

BACKGROUND: Asymptomatic ventricular arrhythmias are common and associated with increased risk of cardiovascular mortality. Cardiac troponins, natriuretic peptides and C-reactive protein (CRP) are also predictive of adverse cardiovascular events in the general population, but limited information is available on the relationship between these biomarkers and ventricular ectopy in a community-based population. The objectives were to evaluate the associations between ventricular ectopic activity and N-terminal pro-B-type natriuretic peptide (NT-proBNP), high sensitivity-troponin I (hs-TnI) and hs-CRP in a community-based setting. METHODS: We performed a 24 h Holter-recording and blood sampling in 498 subjects. Premature ventricular complexes (PVC) were classified as frequent at >5/h and the presence of any bigeminy, trigeminy or non-sustained ventricular tachycardia were classified as complex ventricular ectopy. The associations between biomarkers and ventricular arrhythmias were investigated by univariate and multivariate logistic regression analyses. RESULTS: Frequent PVC's and complex ventricular ectopy were detected in 46 (9%) and 47 (9%) participants respectively, and were associated with significantly (p < 0.001) higher concentrations of NT-proBNP and hs-TnI. The association between NT-proBNP and both frequent PVC's (p = 0.020) and complex ventricular ectopy (p = 0.001) remained significant after adjusting for conventional risk markers in multivariate analyses. CONCLUSION: Increased level of NT-proBNP was independently associated with ventricular ectopy, whereas no independent association was observed between hs-TnI and hs-CRP levels and ventricular ectopy in this community-based sample.

Relation of Erectile Dysfunction to Subclinical Myocardial Injury.

The circulating concentration of cardiac troponin I (cTnI) is an index of subclinical myocardial injury in several patient populations and in the general population. Erectile dysfunction is associated with greater risk for cardiovascular events, but the association with subclinical myocardial injury is not known. We aimed to test the hypothesis that the presence and severity of erectile dysfunction is associated with greater concentrations of cTnI in the general population. The presence and severity of erectile dysfunction was assessed by administering the International Index of Erectile Function 5 (IIEF-5) questionnaire to 260 men aged 30 to 65 years recruited from a population-based study. Concentrations of cTnI were determined by a high-sensitivity (hs) assay. Hs-cTnI levels were significantly higher in subjects with than in those without erectile dysfunction (median 2.9 vs 1.6 ng/l; p <0.001). Men with erectile dysfunction (i.e., IIEF-5 sum score <22) were also significantly older; had a higher systolic blood pressure, lower estimated glomerular filtration rate, higher augmentation index and N-terminal pro-B-type natriuretic peptide; and had a higher prevalence of hypertension, diabetes mellitus, and previous coronary artery disease than subjects without erectile dysfunction. These covariates were adjusted for in a multivariate linear regression model, yet the IIEF-5 sum score remained significantly negatively associated with the hs-cTnI concentration (standardized ß -0.206; p <0.001). In conclusion, the presence and severity of erectile dysfunction is associated with circulating concentrations of hs-cTnI, indicating subclinical myocardial injury independently of cardiovascular risk factors, endothelial dysfunction and heart failure biomarkers.

Severity of obstructive sleep apnea is associated with cardiac troponin I concentrations in a community-based sample: data from the Akershus Sleep Apnea Project.

OBJECTIVES: Previous community-based studies have failed to demonstrate an independent association between OSA and circulating cardiac troponin concentrations, a marker of myocardial injury. However, these studies have used troponin assays with modest analytic sensitivity to detect low-level, chronic increments in troponin levels. Using a highly sensitive troponin I (hs-TnI) assay, we tested the hypothesis that the severity of OSA is associated with myocardial injury independently of comorbidities. DESIGN: Cross-sectional study. SETTING: Community-based. PARTICIPANTS: 514 subjects (54% men, age 48 ± 11 y [mean ± SD]). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: hs-TnI concentrations were measured in fasting morning blood samples and 318 participants (62%) had hs-TnI concentration above the limit of detection ([LoD] 1.2 ng/L). The severity of OSA, expressed as the apnea-hypopnea index (AHI) and nocturnal hypoxemia, was assessed by in-hospital polysomnography. After adjustment for age, gender, estimated creatinine clearance, history of coronary artery disease and hypertension, smoking, diabetes mellitus, systolic blood pressure, heart rate, body mass index, left ventricular hypertrophy, and cholesterol ratio in multivariate linear regression models, higher AHI (standardized ß = 0.12, P = 0.006), lower mean SpO2 (ß = -0.13, P = 0.012) and higher percentage of total sleep time with SpO2 < 90% (ß = 0.12, P = 0.011) were all associated with higher hs-TnI levels in separate models. Additional analyses with hs-TnI categorized in tertiles or using a different strategy for persons with hs-TnI levels below the LoD did not change the results. CONCLUSION: Increased obstructive sleep apnea (OSA) severity is independently associated with higher concentrations of hs-TnI, suggesting that frequent apneas or hypoxemia in OSA may cause low-grade myocardial injury.

Type D personality is associated with increased prevalence of ventricular arrhythmias in community-residing persons without coronary heart disease.

BACKGROUND: Type D personality may be a risk factor for poor outcome in patients with cardiovascular disease. The biological mechanisms underlying this association are poorly understood. The objective of the study was to test the hypotheses that Type D personality is associated with biological markers for sympathetic dysregulation. DESIGN: Cross-sectional community-based study. METHODS: Type D personality was evaluated by DS-14 in 450 persons (46% men), aged between 30 and 65 years. From a Holter-recording, (mean length 18.3 hours), long-term heart rate, ventricular arrhythmias, and heart rate variability (HRV) were registered as markers of sympathetic dysregulation. Traditional cardiovascular risk factors, apnoea-hypopnoea index, medication, and anxiety symptoms were adjusted for. RESULTS: Type D persons had higher long-term averaged heart rate (74 vs. 71 beats/min, p = 0.003), but this difference was attenuated and not significant in the multivariate model (p = 0.078)). There was an increased prevalence of complex ventricular ectopy (bigeminy, trigeminy, or non-sustained ventricular tachycardia; 14 vs. 6%, p = 0.005 in multivariate model). HRV indices did not differ significantly between those with or without Type D personality. Anxiety symptoms did not confound these associations. CONCLUSIONS: Type D personality is independently associated with a higher likelihood of ventricular arrhythmias, which may be implicated in the increased cardiovascular risk observed in persons with Type D personality.

Sex-dependent impact of OSA on digital vascular function.

BACKGROUND: Indexes of associations between OSA and impaired vascular function are mainly based on small, clinic-based studies of conduit artery function in men with severe sleep apnea. Larger population-based studies show no independent associations or associations in women only. Sex differences in OSA-related mortality may exist, and sex differences in vascular function in subjects with OSA need to be explored. We, therefore, assessed whether OSA is associated with digital vascular function in a large population-based sample and whether this association is influenced by sex. METHODS: From a population-based cohort of 30,000 subjects aged 30 to 65 years, we examined 479 subjects (mean age, 48 years; 43% women). Oversampling of subjects at high risk of OSA was performed. Sleep apnea was assessed by inhospital polysomnography. Endothelial function was assessed by digital peripheral arterial tonometry and was expressed as the reactive hyperemia index (RHI). RESULTS: OSA was diagnosed in 266 subjects (55.5%). The RHI was significantly lower in subjects with severe OSA than in those without OSA (P = .002). In the multivariate model for RHI, a significant interaction between OSA and sex was found. In sex-specific multivariate linear regression models, adjusting for conventional cardiovascular risk factors, OSA was an independent predictor of a low RHI in women (P = .006) but not in men. The association between OSA and low RHI in women was independent of postmenopausal status. CONCLUSIONS: In a large population-based sample of middle-aged subjects, OSA was independently associated with impaired digital vascular function in women only.

Impaired endothelial function in persons with obstructive sleep apnoea: impact of obesity.

OBJECTIVE: Obstructive sleep apnoea (OSA) and obesity are both associated with endothelial dysfunction, which precedes the development of atherosclerosis. As obesity is highly prevalent in OSA, we wanted to test the hypothesis that OSA is associated with endothelial dysfunction independently of obesity. DESIGN: Cross-sectional, population-based study. SETTING: Norwegian university hospital. PATIENTS: Seventy-one subjects (median age 44 years, 35% female) were recruited from a population-based study in Norway. Participants were categorised as obese (body mass index (BMI) ≥30 kg/m(2)), non-obese (BMI<30 kg/m(2)) with OSA (apnoea-hypopnoea index (AHI)≥10), or non-obese without OSA (AHI<5). INTERVENTIONS: None. MAIN OUTCOME MEASURES: Endothelial function measured by brachial artery ultrasound and expressed as percentage of flow-mediated dilation (FMD%). RESULTS: When non-obese subjects without OSA were used as the reference (FMD% (mean±SD) 10.1±6.3), endothelial function was found to be impaired in subjects with OSA (FMD% 6.4±3.2) (p=0.003). FMD% did not differ between obese (6.0±3.4) and non-obese (6.7±3.1) OSA subjects (p=0.3). By univariate linear regression analysis, AHI, BMI, gender and baseline brachial artery diameter were significantly associated with FMD%. When these variables were entered into a multivariate model, only AHI was significantly associated with FMD%. CONCLUSIONS: OSA is associated with endothelial dysfunction independently of obesity and conventional risk factors.

Novel cardiovascular risk markers in depression: no association between depressive symptoms and osteoprotegerin or adiponectin in persons at high risk for sleep apnea.

BACKGROUND: Inflammation is believed to play a role in the pathogenesis of both cardiovascular disease and depressive disorders. We hypothesized that circulating concentrations of the novel inflammatory and cardiovascular biomarkers osteoprotegerin (OPG) and adiponectin as well as high sensitivity C-reactive protein (hsCRP) are associated with the severity of depressive symptoms and presence of major depressive disorder (MDD). METHODS: In a cross-sectional population-derived study (Akershus Sleep Apnea Project) 520 persons underwent clinical examination and venous blood sampling. Medical history was obtained and the participants completed the Beck Depression Inventory (BDI). Structured clinical interviews for axis-I disorders including MDD were performed in a subgroup of 288 participants. OPG and adiponectin concentrations were determined by in-house time-resolved immunofluorometric assays. RESULTS: Despite significant correlation with hsCRP (r=0.162, p<0.001), the sum-score of BDI did not correlate with OPG or adiponectin levels (r=0.011, p=0.811 and r=0.055, p=0.210, respectively). Neither circulating OPG nor adiponectin differed between persons with (n=34) and without (n=246) MDD (median±interquartile range: 1.18 (0.96-1.49) vs. 1.17 (0.93-1.57) ug/l and 7.26 (5.13-9.91) vs. 7.39 (5.23-11.37) mg/l, respectively). LIMITATIONS: Causal considerations are not possible, and results in the sub-group of diagnosed participants need careful interpretation due to small sample size. CONCLUSIONS: hsCRP was independently associated with depressive symptoms, but no association between depression severity or presence of MDD and OPG- or adiponectin concentrations was observed in community-residing persons at high risk for obstructive sleep apnea.

Sleep apnoea, anxiety, depression and somatoform pain: a community-based high-risk sample.

Community-based studies that measure both psychiatric diagnoses and obstructive sleep apnoea (OSA) are lacking. This study reports current psychiatric disorders in community-dwelling adults at high risk for OSA identified by the Berlin Questionnaire. Furthermore, associations between OSA and current psychiatric disorders, unadjusted and adjusted for putative confounders, are reported. A subsample of the Akershus Sleep Apnoea Project consisting of 290 adults, aged 30-65 yrs, with positive Berlin Questionnaire screening underwent the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, version IV and polysomnography. Auxiliary analyses of depression are provided. The median apnoea/hypopnoea index score in the sample was 7.7 (interquartile range 2.4-22.2). Major depressive disorder, current anxiety and somatoform pain disorder were diagnosed in 12.4%, 14.8% and 19.3% of participants, respectively. At least one psychiatric disorder was diagnosed in 110 participants. The odds ratio of participants with OSA having a psychiatric disorder compared with participants without OSA was 0.54 (95% CI 0.33-0.88). A negative association did not exist among Berlin Questionnaire low-risk participants. In conclusion, more than one-third of participants in a community-based, Berlin Questionnaire high-risk sample were diagnosed with a psychiatric disorder. A negative association between OSA and psychiatric morbidity was found.

Obstructive sleep apnea is associated with increased high-sensitivity cardiac troponin T levels.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with increased cardiovascular risk. Stress imposed on the myocardium by repeated severe hypoxemia and/or BP surges during sleep may result in subclinical myocardial injury. A high-sensitivity cardiac troponin T (hs-cTnT) assay has been developed. We hypothesized that the severity of OSA, as assessed by the apnea-hypopnea index (AHI), is associated with circulating levels of hs-cTnT in the general population. METHODS: Five hundred five subjects drawn from the general population (age range, 30-65 years; 45% women) underwent in-hospital polysomnography and had morning blood samples drawn. Oversampling of subjects at high risk of OSA was performed. RESULTS: Overall, hs-cTnT was detectable (≥ 3 ng/L) in 216 subjects (42.8%). After categorizing subjects according to AHI cutoffs that correspond to no, mild to moderate, and severe OSA, the proportion of subjects with detectable hs-cTnT levels increased with increasing severity of OSA (P for trend < .001). Multivariate logistic regression with detectable hs-cTnT as the dependent variable was used to further assess the association between OSA and troponin T. After adjustment for significant univariate predictors of detectable hs-cTnT, the association between AHI and hs-cTnT was no longer statistically significant. CONCLUSIONS: The prevalence of detectable hs-cTnT increases in proportion to OSA severity, but this association is likely to be caused by a clustering of cardiovascular risk factors among subjects with OSA.

Circulating cytokine concentrations are not associated with major depressive disorder in a community-based cohort.

OBJECTIVE: The objective was to test the hypotheses that cytokine levels are elevated in community-residing persons at high risk for obstructive sleep apnea with major depressive disorder (MDD) compared to nondepressive persons and that cytokine levels show stronger correlations with somatic than psychological symptoms of depression. METHOD: A case-control study within the cross-sectional Akershus Sleep Apnea Project was performed. Two controls matched for age, gender, metabolic syndrome and obstructive sleep apnea were drawn for each case of MDD. RESULTS: Group comparisons revealed no significant difference in the levels of 17 cytokines [interleukin-1ß, -2,-4, -5, -6, -7, -8, -10, -12(p70), -13 and -17; tumor necrosis factor-α; interferon-γ; granulocyte colony-stimulating factor; granulocyte-monocyte colony-stimulating factor; macrophage chemoattractant protein-1 and monocyte inhibitory protein-1ß] between persons with (n=34) and without MDD (n=68). There was no association between cytokines levels and MDD in multivariate regression analyses. The concentration of interleukin-4 was significantly more positively correlated with psychological than somatic symptoms (r=0.046 vs. -0.143, respectively, P=0.024), while no different correlations were observed for other cytokines. CONCLUSION: The cytokine levels were not elevated in MDD, and cytokine levels were not more strongly associated with somatic than psychological symptoms of depression. The depression-specific effect on inflammation may be weak in community-based samples with prevalent somatic comorbidity.

Body fat and fat-free mass measured by bioelectric impedance spectroscopy and dual-energy X-ray absorptiometry in obese and non-obese adults.

The aim of the present study was to compare body fat mass (FM) and fat-free mass (FFM) estimates by bioelectric impedance spectroscopy (BIS), with respective estimates by dual-energy X-ray absorptiometry (DXA), in obese and non-obese subjects. Body composition was measured in ninety-three obese and non-obese men and women by BIS device, BodyScout (Fresenius Kabi, Bad Homburg, Germany) and DXA device, Lunar iDXA (GE Healthcare, Madison, WI, USA). Mean difference between the methods was analysed by t tests, and Bland-Altman plots were generated to further examine the differences between the methods. Mean difference between the estimates by DXA and BIS (ΔDXA - BIS and Bland-Altman 95 % limits of agreement) were as follows: FM 4·1 ( - 2·9, 11·2) kg and 4·5 ( - 2·9, 11·8) %, FFM - 4·1 ( - 11·2, 2·9) kg and - 4·5 ( - 11·9, 2·9) %, indicating large inter-individual variation and statistically significant underestimation of FM and overestimation of FFM by BIS, as compared to DXA. The underestimation of FMkg (FM measured in kg) and overestimation of FFMkg (FFM measured in kg) were more pronounced in men than in women, and the underestimation of FM% (FM measured in percent) and overestimation of FFM% (FFM measured in percent) were more pronounced in normal weight (BMI = 20·0-24·9 kg/m2) than in overweight and obese (BMI ≥ 25·0 kg/m2) subjects. BIS may be suitable for classification of a population into groups according to FM and FFM. However, the large inter-individual variation suggests that this BIS device with the proprietary software is insufficient for estimation of single individual body FM and FFM.

Obstructive sleep apnea, verbal memory, and executive function in a community-based high-risk population identified by the Berlin Questionnaire Akershus Sleep Apnea Project.

PURPOSE: Cognitive functions in community-dwelling adults at high risk of obstructive sleep apnea have not been described and nor are associations between cognitive functions and obstructive sleep apnea severity fully understood. The study aimed to describe verbal memory and executive function in community-dwelling adults identified by the Berlin Questionnaire and to investigate associations between these cognitive domains and different obstructive sleep apnea severity indicators. METHODS: Among 29,258 age- and gender-stratified persons 30-65 years who received the Berlin Questionnaire by mail, 16,302 (55.7%) responded. From 654 randomly drawn respondents with BQ high risk who were approached for study participation, 290 participants (55.9% males, mean age 48.2 years) were included. Verbal memory was assessed by Rey Auditory Verbal Learning Test and executive function by Stroop test. Obstructive sleep apnea severity indicators were assessed by polysomnography. RESULTS: Mean (standard deviation) verbal learning score was 42.0 (8.9), mean interference time was 31.1 (12.7), median (25th percentile, 75th percentile) apnea-hypopnea index was 7.7 (2.4-22.2), and mean average oxygen saturation was 94.3 (2.0). Verbal learning score was independently associated with average oxygen saturation (ß = 0.721, p = 0.025) in multivariate linear regression models adjusted for putative confounders. Interference time was only related to OSA severity indicators in bivariate analyses. CONCLUSIONS: Verbal memory and executive function impairments were mild in community-dwelling adults at high risk of obstructive sleep apnea. Average oxygen saturation was the indicator of obstructive sleep apnea severity most strongly associated with cognitive function.

Cardiac arrhythmias in obstructive sleep apnea (from the Akershus Sleep Apnea Project).

Increased prevalence of cardiac arrhythmias has been reported in patients with severe obstructive sleep apnea (OSA), but this may not be generalizable to patients from the general population with a milder form of the condition. The aim of this study was to assess the association between cardiac arrhythmias and OSA of mainly mild and moderate severity. In total, 486 subjects (mean age 49 years, 55% men) recruited from a population-based study in Norway underwent polysomnography for OSA assessment and Holter recordings for arrhythmia assessment. Of these, 271 patients were diagnosed with OSA (apnea-hypopnea index [AHI] ≥5, median AHI 16.8, quartiles 1 to 3 8.9 to 32.6). Mean nadir oxygen saturations were 82% and 89% in patients with and without OSA, respectively. Ventricular premature complexes (≥5/hour) were more prevalent in subjects with OSA compared to subjects without OSA (median AHI 1.4, quartiles 1 to 3 0.5 to 3.0) during the night (12.2% vs 4.7%, p = 0.005) and day (14% vs 5.1%, p = 0.002). In multivariate analysis after adjusting for relevant confounders, AHI was independently associated with an increased prevalence of ventricular premature complexes at night (odds ratio per 1-U increase of log-transformed AHI 1.5, 95% confidence interval 1.1 to 2.0, p = 0.008) and during the day (odds ratio 1.37, 95% confidence interval 1.0 to 1.8, p = 0.035). In conclusion, the prevalence of ventricular premature complexes is increased in middle-aged patients with mainly mild or moderate OSA, suggesting an association between OSA and ventricular arrhythmias even in mild OSA.

Major depressive disorder, anxiety disorders, and cardiac biomarkers in subjects at high risk of obstructive sleep apnea.

OBJECTIVE: Cardiac biomarkers may be valuable when exploring potential mechanisms for the association between cardiovascular disease and psychiatric disorders. In subjects at increased risk for obstructive sleep apnea, we examined whether major depressive disorder (MDD), anxiety disorders, or the combination of these was associated with circulating C-reactive protein (CRP), cardiac troponin T (cTnT), or heart rate variability (HRV). METHODS: From the Akershus Sleep Apnea Project, 290 participants were assessed for MDD or any anxiety disorder by a physician using the Structured Clinical Interview for DSM-IV. Fasting blood samples were analyzed with high-sensitivity assays for CRP, cTnT, and HRV calculated from a Holter recording. Age, sex, hypertension, diabetes, hyperlipidemia, obesity, smoking, apnea-hypopnea index, and previous cardiovascular disease were adjusted for. RESULTS: The CRP levels (median [interquartile range], mg/L) were higher in depressive (2.7 [1.1-5.8]) versus nondepressive (1.3 [0.7-3.1], p = .02) and in anxious (2.8 [0.9-5.2]) versus nonanxious (1.3 [0.7-3.1], p = .01). MDD was independently associated with CRP (unstandardized ß = 0.387, p = .04), but anxiety was not (unstandardized ß = 0.298, p = .09). The CRP level was highest in subjects with comorbid MDD and anxiety (3.4 [1.1-7.8]). The unadjusted and adjusted odds ratios (95% confidence interval) for having measurable cTnT (> 3 ng/L) were 0.49 (0.24-1.07) and 0.92 (0.31-2.67) for MDD versus nondepressive and 0.38 (0.18-0.80) and 0.61 (0.30-2.05) for anxiety versus nonanxiety, respectively. HRV did not vary between groups. CONCLUSIONS: Although CRP was increased both in MDD and anxiety disorders, patients with comorbid MDD and anxiety may be particularly prone to increased systemic inflammation. Neither MDD nor anxiety disorders were associated with low-level myocardial damage or HRV.

Prevalence of cardiovascular risk factors and concentration of C-reactive protein in Type D personality persons without cardiovascular disease.

BACKGROUND: Type D personality is associated with poor cardiovascular outcome in patients with coronary or peripheral arterial disease. Whether Type D personality is associated with cardiovascular risk in persons without overt cardiovascular disease remains unknown. We hypothesized that Type D personality is associated with higher prevalence of traditional cardiovascular risk factors and higher concentration of C-reactive protein. DESIGN: Cross-sectional study. METHODS: Type D personality was assessed in 453 participants without cardiovascular disease derived from an epidemiological study of obstructive sleep apnoea. An evaluation of obesity, lipid status, diabetes, blood pressure, heart rate, smoking, leisure-time physical activity and high-sensitivity C-reactive protein was performed. RESULTS: Smoking (43% vs. 21%, P < 0.001) and low leisure-time physical activity (<3 hours/week, 57% vs. 40%, P = 0.003) were more prevalent, and heart rate (mean (standard deviation), 75 (10) vs. 71 (9), P = 0.001) and body mass index was higher (29.8 (6.0) vs. 28.4 (4.5) kg/m2, P = 0.009) in Type D compared to non-Type D participants. The total number of risk factors was significantly higher in Type D than non-Type D participants (3.4 (1.3) vs. 3.0 (1.2), P = 0.004). The concentration of C-reactive protein was higher in participants with Type D personality (median, interquartile range 1.6, 0.7-3.4 vs. 1.1, 0.6-2.6, P = 0.047), although not statistically significant after adjustment for possible mediating factors. CONCLUSIONS: Among participants at high risk of cardiovascular disease, presence of Type D personality was associated with elevated body mass index and unhealthy behaviour such as smoking and low physical activity, which may have mediated the elevated concentration of C-reactive protein.

A Norwegian population-based study on the risk and prevalence of obstructive sleep apnea. The Akershus Sleep Apnea Project (ASAP).

The Berlin Questionnaire (BQ) is a widely used screening tool for obstructive sleep apnea (OSA), but its performance in the general population setting is unknown. The prevalence of OSA in middle-aged adults is not known in Norway. Accordingly, the aims of the current study were to evaluate the utility of the BQ for OSA screening in the general population and to estimate the prevalence of OSA in Norway. The study population consisted of 29,258 subjects (aged 30-65 years, 50% female) who received the BQ by mail. Of these, 16,302 (55.7%) responded. Five-hundred and eighteen subjects were included in the clinical sample and underwent in-hospital polysomnography. Screening properties and prevalence were estimated by a statistical model that adjusted for bias in the sampling procedure. Among the 16,302 respondents, 24.3% (95% confidence interval (CI)=23.6-25.0%) were classified by the BQ to be at high-risk of having OSA. Defining OSA as an apnea-hypopnea index (AHI) ≥5, the positive predictive value of the BQ was estimated to be 61.3%, the negative predictive value 66.2%, the sensitivity 37.2% and the specificity 84.0%. Estimated prevalences of OSA were 16% for AHI≥5 and 8% for AHI≥15. In conclusion, the BQ classified one out of four middle-aged Norwegians to be at high-risk of having OSA, but the screening properties of the BQ were suboptimal. The estimated prevalence of OSA was comparable to previous estimates from general populations in the USA, Australia and Europe.