Association between obstructive sleep apnea and persistent postural-perceptual dizziness.

BACKGROUND: Obstructive sleep apnea (OSA) has been linked to vestibular dysfunction, but no prior studies have investigated the relationship between Persistent Postural-Perceptual Dizziness (PPPD), a common cause of chronic dizziness, and OSA. OBJECTIVE AND METHODS: We determined the frequency of OSA in an uncontrolled group of PPPD patients from a tertiary dizziness clinic based on polysomnogram (PSG). We then assessed the sensitivity and specificity of common OSA questionnaires in this population. RESULTS: Twenty-five patients with PPPD underwent PSG (mean age 47, 60% female, mean BMI 29.5). A majority, or 56%, of patients were diagnosed with OSA, and in most, the OSA was severe. OSA patients were older (56 years versus 40 years, p = 0.0006) and had higher BMI (32 versus 26, p = 0.0078), but there was no clear gender bias (56% versus 64% female, p = 1.00). The mean sensitivity and specificity of the STOP BANG questionnaire for detecting OSA was 86% and 55%, respectively. Sensitivity and specificity of the Berlin Questionnaire was 79% and 45%, respectively. CONCLUSIONS: The prevalence of OSA was much higher in our small PPPD group than in the general population. Screening questionnaires appear to demonstrate good sensitivity to detect PPPD patients at risk of OSA in this small study. Future studies should confirm these findings and determine whether treatment of OSA improves symptoms in PPPD.

Effects of CPAP on Blood Pressure and Sympathetic Activity in Patients With Diabetes Mellitus, Chronic Kidney Disease, and Resistant Hypertension.

BACKGROUND: Patients with obstructive sleep apnea (OSA) have increased sympathetic activity and frequently also have resistant hypertension (HTN). Treatment of OSA with continuous positive airway pressure (CPAP) decreases awake and sleep blood pressure (BP) and sympathetic activity. This study was designed to assess the effect of treatment of OSA with CPAP on sympathetic activity and BP in patients with diabetes mellitus (DM), chronic kidney disease (CKD), and resistant HTN. METHODS: This was a randomized, double-blind, sham-controlled trial. Patients with DM, CKD, and resistant HTN were randomized to treatment with a therapeutic or subtherapeutic CPAP for 6 weeks. They underwent 24-hour ambulatory BP monitoring and assessment of muscle sympathetic nerve activity before and after 6 weeks on treatment. RESULTS: Treatment with therapeutic CPAP caused significant decreases in awake systolic and diastolic BP from 144 to 136 mm Hg (P = 0.004) and from 79 to 74 mm Hg (P = 0.004) and in sleep BP from 135 to 119 mm Hg (P = 0.045) and from 75 to 65 mm Hg (P = 0.015) compared with treatment with subtherapeutic CPAP. In contrast, treatment with therapeutic CPAP did not decrease sympathetic activity as assessed from muscle sympathetic nerve activity. CONCLUSIONS: Decrease in BP by treatment with CPAP in patients with DM, CKD, and OSA indicates the contribution of OSA to severity of HTN in this clinical scenario. Decrease in BP in the absence of changes in sympathetic activity is suggestive that other mechanisms induced by OSA play a larger role in the maintenance of HTN in these patients.

CONTEXTE: Les patients atteints d'apnée obstructive du sommeil (AOS) présentent une activité sympathique accrue qui est souvent accompagnée d'hypertension artérielle (HTA) réfractaire. Le traitement de l'AOS par ventilation en pression positive continue (CPAP, pour Continuous Positive Airway Pressure) diminue la pression artérielle (PA) à l'état de veille et durant le sommeil ainsi que l'activité sympathique. Cette étude était conçue pour évaluer l'effet du traitement de l'AOS par CPAP sur l'activité sympathique et la PA chez des patients atteints de diabète sucré (DS), d'insuffisance rénale chronique (IRC) et d'HTA réfractaire. MÉTHODOLOGIE: Il s'agissait d'une étude à double insu et à répartition aléatoire contrôlée par simulation. Les patients atteints de DS, d'IRC et d'HTA réfractaire ont été répartis de façon aléatoire pour recevoir un traitement par CPAP thérapeutique ou subthérapeutique pendant 6 semaines. Une surveillance ambulatoire de la PA et une évaluation de l'activité nerveuse sympathique musculaire sur 24 h ont été effectuées chez les patients avant et après 6 semaines de traitement. RÉSULTATS: Comparativement à la CPAP subthérapeutique, la CPAP thérapeutique a entraîné une diminution significative de la PA systolique et de la PA diastolique à l'état de veille, qui sont passées respectivement de 144 à 136 mmHg (p = 0,004) et de 79 à 74 mmHg (p = 0,004). La même observation a été faite à l'égard de la PA systolique et de la PA diastolique durant le sommeil, qui sont passées respectivement de 135 à 119 mmHg (p = 0,045) et de 75 à 65 mmHg (p = 0,015). En revanche, l'évaluation de l'activité nerveuse sympathique musculaire n'a révélé aucune diminution de l'activité sympathique associée au traitement par CPAP thérapeutique. CONCLUSIONS: La diminution de la PA associée au traitement par CPAP chez les patients atteints de DS, d'IRC et d'AOS indique que l'AOS contribue à l'intensité de l'HTA dans ce scénario clinique. La diminution de la PA en l'absence de modification de l'activité sympathique laisse supposer que d'autres mécanismes induits par l'AOS jouent un rôle plus important dans le maintien de l'HTA chez ces patients.

Comparative effectiveness and safety of pharmacological and non-pharmacological interventions for insomnia: an overview of reviews.

BACKGROUND: This review aimed to assess the existing evidence regarding the clinical effectiveness and safety of pharmacological and non-pharmacological interventions in adults with insomnia and identify where research or policy development is needed. METHODS: MEDLINE, Embase, PsycINFO, The Cochrane Library, and PubMed were searched from inception until June 14, 2017, along with relevant gray literature sites. Two reviewers independently screened titles/abstracts and full-text articles, and a single reviewer with an independent verifier completed charting, data abstraction, and quality appraisal. RESULTS: A total of 64 systematic reviews (35 with meta-analysis) were included after screening 5024 titles and abstracts and 525 full-text articles. Eight of the included reviews were rated as high quality using the Assessment of Multiple Systematic Reviews 2 (AMSTAR2) tool, and over half of the included articles (n = 40) were rated as low or critically low quality. Consistent evidence of effectiveness across multiple outcomes based on more than one high- or moderate quality review with meta-analysis was found for zolpidem, suvorexant, doxepin, melatonin, and cognitive behavioral therapy (CBT), and evidence of effectiveness across multiple outcomes based on one high-quality review with meta-analysis was found for temazepam, triazolam, zopiclone, trazodone, and behavioral interventions. These interventions were mostly evaluated in the short term (< 16 weeks), and there was very little harms data available for the pharmacological interventions making it difficult to evaluate their risk-benefit ratio. CONCLUSIONS: Assuming non-pharmacological interventions are preferable from a safety perspective CBT can be considered an effective first-line therapy for adults with insomnia followed by other behavioral interventions. Short courses of pharmacological interventions can be supplements to CBT or behavioral therapy; however, no evidence regarding the appropriate duration of pharmacological therapy is available from these reviews. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42017072527.

Changes in sleep duration and recreational screen time among Canadians, 1998-2010.

It is commonly claimed that sleep duration has declined in recent years - over a period coinciding with a marked increase in personal electronics and communications use. The aim of this study was to assess change in sleep duration among Canadians from 1998 to 2010, and examine any associations with non-work-related screen time. The analysis uses population-representative data from Statistics Canada's General Social Survey cycles of 1998 and 2010; the respective samples numbered 10 749 and 15 390 individuals. Response rates were 80% in 1998 and 55% in 2010. Respondents were aged 15 years and older, residing in private households in the 10 Canadian provinces. The General Social Survey is administered by computer-assisted telephone interviewing. Data on sleep duration (excluding naps outside essential sleep time) and recreational screen time were obtained using a 24-h time-use diary. Survey weights were applied to adjust for non-response and non-landline households. Frequencies (respondent characteristics) and averages (time-use variables) were estimated by age group and sex. Sleep duration was examined by weighted quartile of screen time. Confidence intervals (95%) were calculated around estimates. Average sleep duration increased from 8.1 h in 1998 to 8.3 h in 2010. Average screen time increased from 140 min in 1998 to 154 min in 2010. Sleep duration and screen time were positively related in both years. The percentage of people averaging less than 6 h sleep decreased from 9.6% in 1998 to 8.6% in 2010. Between 1998 and 2010, increases in screen time did not occur at the expense of sleep duration.

Effects of short-term continuous positive airway pressure on myocardial sympathetic nerve function and energetics in patients with heart failure and obstructive sleep apnea: a randomized study.

BACKGROUND: Heart failure with reduced ejection fraction and obstructive sleep apnea (OSA), 2 states of increased metabolic demand and sympathetic nervous system activation, often coexist. Continuous positive airway pressure (CPAP), which alleviates OSA, can improve ventricular function. It is unknown whether this is due to altered oxidative metabolism or presynaptic sympathetic nerve function. We hypothesized that short-term (6-8 weeks) CPAP in patients with OSA and heart failure with reduced ejection fraction would improve myocardial sympathetic nerve function and energetics. METHODS AND RESULTS: Forty-five patients with OSA and heart failure with reduced ejection fraction (left ventricular ejection fraction 35.8±9.7% [mean±SD]) were evaluated with the use of echocardiography and 11C-acetate and 11C-hydroxyephedrine positron emission tomography before and ≈6 to 8 weeks after randomization to receive short-term CPAP (n=22) or no CPAP (n=23). Work metabolic index, an estimate of myocardial efficiency, was calculated as follows: (stroke volume index×heart rate×systolic blood pressure÷Kmono), where Kmono is the monoexponential function fit to the myocardial 11C-acetate time-activity data, reflecting oxidative metabolism. Presynaptic sympathetic nerve function was measured with the use of the 11C-hydroxyephedrine retention index. CPAP significantly increased hydroxyephedrine retention versus no CPAP (Δretention: +0.012 [0.002, 0.021] versus -0.006 [-0.013, 0.005] min(-1); P=0.003). There was no significant change in work metabolic index between groups. However, in those with more severe OSA (apnea-hypopnea index>20 events per hour), CPAP significantly increased both work metabolic index and systolic blood pressure (P<0.05). CONCLUSIONS: In patients with heart failure with reduced ejection fraction and OSA, short-term CPAP increased hydroxyephedrine retention, indicating improved myocardial sympathetic nerve function, but overall did not affect energetics. In those with more severe OSA, CPAP may improve cardiac efficiency. Further outcome-based investigation of the consequences of CPAP is warranted. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00756366.

The association between personal care products and lung function.

PURPOSE: Chemical exposures are important determinants of respiratory health. The objective of the present study was to determine the association between the use of personal care products, which may contain respirable components, and lung function. METHODS: Using questionnaire and spirometry data collected during the Canadian Health Measures population survey, the association was tested between 1-second forced expiratory volume (FEV(l)) and forced vital capacity (FVC) expressed as a percentage of predicted, and the frequency of use of personal care products categorized as eye makeup, fragrances, hairstyle products, lipstick, and scented body products. RESULTS: Five thousand sixteen of the 5604 participants in the survey reported using at least one personal care product in the past 3 months. Among men and women, an interquartile increase in hairstyle products was associated with an approximate 2% decrease in both FEV(1) and FVC (P < .05). Among women, each product category was associated with a significant decrease in lung function with the largest observed effect being a 4.08% (95% confidence interval, 7.71-0.45) decrease in FVC associated with an interquartile range increase in the frequency of use of scented body products. CONCLUSIONS: This study provides data suggesting that using personal care products may have a small adverse effect on lung function. Further research is warranted to investigate this possibility.

The influence of air pollution on cardiovascular and pulmonary function and exercise capacity: Canadian Health Measures Survey (CHMS).

BACKGROUND: Air pollution has been associated with adverse cardiovascular effects. OBJECTIVE: To measure the association between air pollution, spirometry, blood pressure, and exercise capacity. METHODS: We used data from 5604 subjects collected during the Canada Health Measures Survey to test the association between air pollution measured on the day of the survey and spirometry (n=5011 subjects), blood pressure, and exercise capacity (n=3789 subjects). RESULTS: An interquartile range (IQR) increase in ozone (17.0 ppb) was significantly associated with a 0.883% higher resting heart rate, a 0.718% higher systolic and 0.407% higher diastolic blood pressure, a 0.393% lower FEV1/FVC expressed as a percentage of predicted, and a 1.52% reduction in the aerobic fitness score (p<0.05). Resting systolic and diastolic blood pressure were approximately 0.5 mmHg higher for an (IQR 4.5 µg/m3) increase in PM2.5 (IQR 4.5 µg/m3) and 1 mmHg higher for a 12.6 ppb increase in NO2 (IQR 12.6 ppb). An increase in PM2.5 was also associated with an approximate 0.4% decrease in percent predicted FEV1 and FVC (p<0.05). CONCLUSION: Exposure to higher concentrations of air pollution was associated with higher resting blood pressure and lower ventilatory function. Ozone was associated with reduced exercise capacity.

Air pollution and emergency department visits for cardiac and respiratory conditions: a multi-city time-series analysis.

BACKGROUND: Relatively few studies have been conducted of the association between air pollution and emergency department (ED) visits, and most of these have been based on a small number of visits, for a limited number of health conditions and pollutants, and only daily measures of exposure and response. METHODS: A time-series analysis was conducted on nearly 400,000 ED visits to 14 hospitals in seven Canadian cities during the 1990 s and early 2000s. Associations were examined between carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), and particulate matter (PM 10 and PM2.5), and visits for angina/myocardial infarction, heart failure, dysrhythmia/conduction disturbance, asthma, chronic obstructive pulmonary disease (COPD), and respiratory infections. Daily and 3-hourly visit counts were modeled as quasi-Poisson and analyses controlled for effects of temporal cycles, weather, day of week and holidays. RESULTS: 24-hour average concentrations of CO and NO2 lag 0 days exhibited the most consistent associations with cardiac conditions (2.1% (95% CI, 0.0-4.2%) and 2.6% (95% CI, 0.2-5.0%) increase in visits for myocardial infarction/angina per 0.7 ppm CO and 18.4 ppb NO2 respectively; 3.8% (95% CI, 0.7-6.9%) and 4.7% (95% CI, 1.2-8.4%) increase in visits for heart failure). Ozone (lag 2 days) was most consistently associated with respiratory visits (3.2% (95% CI, 0.3-6.2%), and 3.7% (95% CI, -0.5-7.9%) increases in asthma and COPD visits respectively per 18.4 ppb). Associations tended to be of greater magnitude during the warm season (April - September). In particular, the associations of PM 10 and PM2.5 with asthma visits were respectively nearly three- and over fourfold larger vs. all year analyses (14.4% increase in visits, 95% CI, 0.2-30.7, per 20.6 microg/m3 PM 10 and 7.6% increase in visits, 95% CI, 5.1-10.1, per 8.2 microg/m3 PM2.5). No consistent associations were observed between three hour average pollutant concentrations and same-day three hour averages of ED visits. CONCLUSION: In this large multicenter analysis, daily average concentrations of CO and NO2 exhibited the most consistent associations with ED visits for cardiac conditions, while ozone exhibited the most consistent associations with visits for respiratory conditions. PM 10 and PM2.5 were strongly associated with asthma visits during the warm season.

Acute and chronic effects of continuous positive airway pressure therapy on left ventricular systolic and diastolic function in patients with obstructive sleep apnea and congestive heart failure.

BACKGROUND: Obstructive sleep apnea (OSA) may contribute to the pathogenesis of congestive heart failure (CHF). Nocturnal continuous positive airway pressure (CPAP) therapy can alleviate OSA and may have a role in the treatment of CHF patients. OBJECTIVES: To investigate the acute and chronic effects of CPAP therapy on left ventricular systolic function, diastolic function and filling pressures in CHF patients with OSA. METHODS: Twelve patients with stable CHF (New York Heart Association II or III, radionuclide ejection fraction lower than 40%) underwent overnight polysomnography to detect OSA. In patients with OSA (n=7), echocardiography was performed at baseline (awake, before and during acute CPAP administration) and after 6.9+/-3.3 weeks of nocturnal CPAP therapy. Patients without OSA (n=5) did not receive CPAP therapy, but underwent a baseline and follow-up echocardiogram. RESULTS: In CHF patients with OSA, acute CPAP administration resulted in a decrease in stroke volume (44+/-15 mL versus 50+/-14 mL, P=0.002) and left ventricular ejection fraction ([LVEF] 34.8+/-5.0% versus 38.4+/-3.3%, P=0.006) compared with baseline, but no change in diastolic function or filling pressures (peak early diastolic mitral annular velocity [Ea]: 6.0+/-1.6 cm/s versus 6.3+/-1.6 cm/s, P not significant; peak early filling velocity to peak late filling velocity [E/A] ratio: 1.05+/-0.74 versus 1.00+/-0.67, P not significant; E/Ea ratio: 10.9+/-4.1 versus 11.3+/-4.1, P not significant). In contrast, chronic CPAP therapy resulted in a trend to an increase in stroke volume (59+/-19 mL versus 50+/-14 mL, P=0.07) and a significant increase in LVEF (43.4+/-4.8% versus 38.4+/-3.3%, P=0.01) compared with baseline, but no change in diastolic function or filling pressures (Ea: 6.2+/-1.2 cm/s versus 6.3+/-1.6 cm/s, P not significant; E/A ratio: 1.13+/-0.61 versus 1.00+/-0.67, P not significant; E/Ea ratio: 12.1+/-2.7 versus 11.3+/-4.1, P not significant). There was no change in left ventricular systolic function, diastolic function or filling pressures at follow-up in CHF patients without OSA. CONCLUSIONS: Acute CPAP administration decreased stroke volume and LVEF in stable CHF patients with OSA. In contrast, chronic CPAP therapy for seven weeks improved left ventricular systolic function, but did not affect diastolic function or filling pressures. The potential clinical implications of the discrepant effects of CPAP therapy on left ventricular systolic and diastolic function in CHF patients with OSA warrant further study.

The feasibility of adding fetal heart rate to the nocturnal polysomnogram.

STUDY OBJECTIVES: To demonstrate that fetal heart rate measured by ultrasound can be successfully captured and monitored throughout the nocturnal polysomnogram. METHODS: Fetal heart rate by ultrasound using an abdominal belt (Hewlett Packard Fetal Monitor 8040A) was measured during 1 overnight polysomnogram in volunteers in late pregnancy and added to a digitized polysomnography system (Alice 4, Respironics). RESULTS: In 6 women with a single fetus in their third trimester, the fetal heart rate monitor band only infrequently needed to be readjusted. Fetal kicks and movements resulted in signal loss, usually with subsequent recapture without having to awaken the mother. CONCLUSIONS: Fetal heart rate, 1 of the classic signals of fetal distress, can be added to the nocturnal polysomnogram with minimal disruption of maternal sleep and with signal capture throughout the night.

The effects of continuous positive airway pressure on myocardial energetics in patients with heart failure and obstructive sleep apnea.

OBJECTIVES: We sought to examine the short-term and longer term (6-week) effects of continuous positive airway pressure (CPAP) on myocardial energetics. BACKGROUND: Obstructive sleep apnea (OSA) and heart failure (HF) are both states of increased afterload and metabolic demand. Treatment with CPAP may initially reduce stroke volume but subsequently improves left ventricular function. However, it is not clear whether CPAP therapy favorably affects myocardial energetics and hence improves cardiac efficiency. METHODS: Twelve patients with HF were divided into two groups: 7 patients with OSA were treated with CPAP (group I), and 5 patients without OSA served as a control group (group II). Oxidative metabolism was measured using the mono-exponential fit of the myocardial [(11)C] acetate positron emission tomography time-activity curve (k-mono). Myocardial efficiency was derived using the work metabolic index (WMI = [heart rate x stroke volume index x systolic blood pressure]/k-mono) measured at baseline, during short-term CPAP, and after 6 +/- 3 weeks of CPAP. RESULTS: In group I, short-term CPAP tended to reduce SVI (p = 0.063) and reduced oxidative metabolism (p = 0.031). Work metabolic index did not change. However, longer term CPAP improved left ventricular ejection fraction (38.4 +/- 3.3% to 43.4 +/- 4.8%, p = 0.031), tended to reduce oxidative metabolism (0.047 +/- 0.012 to 0.040 +/- 0.008 min(-1), p = 0.078), and improved WMI (7.13 +/- 2.82 x 10(6) to 8.17 +/- 3.06 x 10(6) mm Hg.ml/m(2), p = 0.031). In group II (control), these parameters did not change. CONCLUSIONS: In this cohort of patients with HF and OSA, short-term CPAP decreased oxidative metabolism and tended to decrease SVI, but did not alter cardiac efficiency. Longer term CPAP improved cardiac efficiency, indicating an energy-sparing effect. These effects may contribute to the benefits of CPAP therapy.

Exposure time and place: do COPD patients differ from the general population?

Time-activity patterns in a panel of 70 patients with COPD (35 males) are compared to an age-matched subgroup from the randomly sampled Canadian Human Activity Pattern Survey. Total time indoors and outdoors were similar in both groups but significantly more indoor time in COPD subjects was spent at home than the indoor time of controls, who were more often indoors elsewhere. As part of improving their indoor air at home, COPD subjects were significantly more likely to have air conditioning at home. These results suggest that while outdoor air exposure strategies need not differ in COPD subjects from normals, indoor mitigation strategies should emphasize source pollutant control in the patient's home.

It's about time: a comparison of Canadian and American time-activity patterns.

This study compares two North American time-activity data bases: the National Human Activity Pattern Survey (NHAPS) of 9386 interviewees in 1992-1994 in the continental USA with the Canadian Human Activity Pattern Survey (CHAPS) of 2381 interviewees in 1996-1997 in four major Canadian cities. Identical surveys and methodology were used to collect this data: random sample telephone selection within the identified telephone exchanges, computer-assisted telephone interviews, overselection of children and weekends in the 24-h recall diary and the same interviewers. Very similar response rates were obtained: 63% (NHAPS) and 64.5% (CHAPS). Results of comparisons by age within major activity and location groups suggest activity and location patterns are very similar (most differences being less than 1% or 14 min in a 24-h day) with the exception of seasonal differences. Canadians spend less time outdoors in winter and less time indoors in summer than their U.S. counterparts. When exposure assessments use time of year or outdoor/indoor exposure gradients, these differences may result in significant differences in exposure assessments. Otherwise, the 24-h time activity patterns of North Americans are remarkably similar and use of the combined data set for some exposure assessments may be feasible.