The effects of sleep-disordered breathing on arterial stiffness are modulated by age

Observational study on the influence of averaging time on oximetry results in infants and children

AIM

Oximetry values are influenced by the averaging time (AT) used. We aimed to evaluate the effect of different ATs on number, duration, mean single event and total integral of desaturations in preterm infants and children to convert between parameters obtained with different ATs.

METHODS

In a prospective observational study, 49 children underwent sleep laboratory-based polysomnography and 15 preterm infants were studied in the intensive care unit. Their raw red-to-infrared-saturation-data were reprocessed using seven different ATs (3-16 seconds). Desaturation thresholds were <80% (infants) and <90% (children), conversion formulas and their median percentage errors were calculated.

RESULTS

We found a linear relationship between the logarithms of the ATs and those of the desaturation parameters, leading to a conversion formula with different exponents. Based on this relationship, the number of desaturations decreased from AT = 3s to AT = 16s by factor 0.28 (children) and 0.18 (infants); total oxygen saturation integral decreased by factor 0.72 (children) and 0.48 (infants). The desaturation duration increased by factor 1.89 (children) and 3.34 (infants).

CONCLUSION

The number and total integral decreased, but the duration and mean single event integral increased with increasing AT. These changes were stronger in infants. Conversion formulas may facilitate comparisons between studies using different averaging times.

Arterial stiffness in people with Type 2 diabetes and obstructive sleep apnoea

AIMS

To examine whether people with Type 2 diabetes with concurrent obstructive sleep apnoea have increased arterial stiffness as compared with people with Type 2 diabetes without obstructive sleep apnoea.

METHODS

In a study with a case-control design, 40 people with Type 2 diabetes and treatment-naïve moderate to severe obstructive sleep apnoea (Apnoea-Hypopnoea Index ≥15) and a control group of 31 people with Type 2 diabetes without obstructive sleep apnoea (Apnoea-Hypopnoea Index <5) were examined. Obstructive sleep apnoea status was evaluated using the ApneaLink^® + home-monitoring device (Resmed Inc., San Diego, CA, USA), providing the Apnoea-Hypopnoea Index scores. Arterial stiffness was assessed according to carotid-femoral pulse wave velocity using the Sphygmocor device and the oscillometric Mobil-O-Graph^® (I.E.M. GmbH, Stolberg, Germany).

RESULTS

Carotid-femoral pulse wave velocity was not significantly different between participants with Type 2 diabetes with obstructive sleep apnoea and those without obstructive sleep apnoea (10.7±2.2 m/s vs 10.3±2.1 m/s; P=0.513), whereas oscillometric pulse wave velocity was significantly higher in participants with Type 2 diabetes with obstructive sleep apnoea than in those without obstructive sleep apnoea (9.5±1.0 m/s vs 8.6±1.4 m/s; P=0.002). In multiple regression analysis, age (P=0.002), gender (men; P=0.018) and HbA_1c (P=0.027) were associated with carotid-femoral pulse wave velocity, and systolic blood pressure (P=0.004) and age (P<0.001) were associated with oscillometric pulse wave velocity. After adjustment, presence of obstructive sleep apnoea was not independently associated with pulse wave velocity whether assessed by tonometry or oscillometry.

CONCLUSION

In conclusion, the present study did not find an age- and blood pressure-independent association between moderate to severe obstructive sleep apnoea and arterial stiffness in non-sleepy people with Type 2 diabetes. (Clinical trial registration number: NCT02482584).

"Sleep disordered breathing and ECG R-wave to radial artery pulse delay, The Multi-Ethnic Study of Atherosclerosis"

BACKGROUND

Electrocardiography R-wave to radial artery pulse delay (RRD) represents pulse transit time inclusive of pre-ejection period (PEP) and arterial pulse propagation time. RRD is proposed to largely reflect arterial stiffness when PEP is accounted for (shorter RRD = higher arterial stiffness). Sleep disordered breathing (SDB) causes intermittent hypoxemia and sympathetic activation, which negatively influences vascular function. We aimed to examine the association of measures of SDB with RRD.

METHODS

Our sample consisted of participants in the Multi-Ethnic Study of Atherosclerosis without prevalent cardiovascular disease who underwent a daytime arterial elasticity exam, cardiac magnetic resonance imaging (MRI), and overnight polysomnography. SDB measures of interest included apnea hypopnea index (AHI) and oxygen desaturation index (ODI) (N = 1173). RRD was regressed on each measure of SDB separately, with adjustment for other cardiovascular risk factors as well as for correlates of the PEP, another component of RRD, by including cardiac MRI measures of contractility and preload.

RESULTS

In multivariate analysis, among measures of SDB, ODI, a marker of intermittent hypoxemia, was inversely associated with RRD (β = -60.2 msec per SD [15.5/hr], p = 0.04). No significant association was found with AHI. In gender stratified analyses, ODI and AHI were predictive of RRD in men only (β = -111.3 msec per SD [15.5/hr], p = 0.01 and β = -100.3 msec per SD [16.1/hr], p = 0.02 respectively).

CONCLUSION

Severity of SDB as measured by ODI was associated with RRD, a marker of arterial stiffness. Thus, association of RRD with measures of SDB appears to be gender-dependent.

Obstructive sleep apnoea is associated with progression of arterial stiffness independent of obesity in participants without hypertension: A KoGES Prospective Cohort Study

Accumulating evidence shows that obstructive sleep apnoea (OSA) is associated with an increased risk of cardiovascular disease. However, there are no published prospective studies on the relationship between OSA and the progression of arterial stiffness. We hypothesised that OSA would increase the risk of arterial stiffness progression, independent of obesity. In the present large cohort study, 1921 participants were randomly selected and underwent polysomnography. The brachial ankle pulse wave velocity (baPWV) was measured at baseline and during the follow-period using a standard protocol. Elevated baPWV was defined as a value greater than the cut-off of highest tertile level in the complete study cohort. The percentage of elevated baPWV and the ΔbaPWV significantly increased with OSA severity. After adjusting for potential confounding factors, participants with moderate-to-severe OSA without hypertension had a significantly higher risk of elevated ΔbaPWV than those without OSA. More importantly, using multivariate mixed-effect models, we found that the ΔbaPWV over 6 years significantly differed according to OSA severity. Therefore, moderate-to-severe OSA in participants without hypertension was a predictor of future burden of arterial stiffness progression, independent of obesity, suggesting that it may contribute to the increased risk of cardiovascular disease.

Factors related to pediatric obstructive sleep apnea-hypopnea syndrome in children with attention deficit hyperactivity disorder in different age groups

This study aimed to retrospectively investigate the factors related to pediatric obstructive sleep apnea-hypopnea syndrome (OSAHS) with attention deficit hyperactivity disorder (ADHD) in children younger than 6 years and those older than 6 years.A total of 437 children who were hospitalized due to OSAHS between January 2014 and December 2014 were retrospectively reviewed. The children were further divided into OSAHS group and OSAHS + ADHD group. The general characteristics, OSA-18 quality of life, intention-hyperactivity score, and polysomnographic parameters (apnea-hypopnea index and the lowest oxygen saturation) were collected and compared between groups.There were 298 boys and 139 girls with the male to female ratio of 2.14:1. ADHD was found in 146 children including 105 boys and 41 girls with the male to female ratio of 2.56:1. Of these children, 31.62% and 35.46% had concomitant ADHD in children aged 4 to 5 years and those aged 6 to 11 years, respectively. In children aged 4 to 5 years, the incidence of allergic rhinitis was significantly higher (P = .016) and the adenoid hypertrophy was more severe (P = .001) in those with concomitant ADHD. In children aged 6 to 11 years, the tonsil hypertrophy was more severe in those with concomitant ADHD (P = .019). In children with concomitant ADHD, OSA-18 score was higher than in those with OSAHS alone (P < .001). Higher frequency of respiratory events (P < .001) and more severe hypoxia (P < .001) were found in children with concomitant ADHD than in those with OSAHS alone.As high as 30% of OSAHS children have concomitant ADHD, and the incidence of ADHD in OSAHS children is increasing over age. Boys are more likely to develop OSAHS and incidence of ADHD in OSAHS boys is higher than in OSAHS girls. In addition, risk factors of ADHD also vary between age groups. The ADHD is related to the severity of allergic rhinitis and adenoid hypertrophy in children aged 4 to 5 years, and to the severity of tonsil hypertrophy in children aged 6 to 11 years. Hypoxia may be an important factor causing ADHD. OSAHS should be treated as early as possible to reduce the incidence of ADHD in children.

The association between sleep-disordered breathing and aortic stiffness in a community cohort

OBJECTIVE

Sleep-disordered breathing is associated with hypertension and cardiovascular disease. Increased aortic stiffness is one possible linking mechanism. We evaluated the association between sleep-disordered breathing and aortic stiffness in a community-based sample.

METHODS

Our community-based cross-sectional observational study included 381 participants from the Framingham Heart Study (55% women, mean age 58.0 S.D. = 9.4 years, 51% ethnic minorities). Polysomnographically derived apnea-hypopnea index and CT90% (cumulative % sleep time with oxyhemoglobin saturation <90%) quantified sleep-disordered breathing severity. Carotid-femoral pulse wave velocity, the gold-standard measure of aortic stiffness, was calculated using arterial applanation tonometry-derived waveforms and body surface measured transit distance. We assessed associations between sleep-disordered breathing and carotid-femoral pulse wave velocity using multivariable regression. We adjusted for age, sex, race, body mass index, diabetes, alcohol consumption, hormone replacement therapy, cholesterol/high-density lipoprotein, lipid-lowering therapy, anti-hypertensive medication, smoking, hypertension, and prevalent cardiovascular disease.

RESULTS

After multivariable adjustment, carotid-femoral pulse wave velocity was associated with both apnea-hypopnea index (β = 0.03, 95% CI: 0.002-0.07, p= 0.04) and CT90% (β = 0.05, 95% CI: 0.005-0.1, p= 0.03). The adjusted mean carotid-femoral pulse wave velocity was 9.43 (95% CI: 9.12-9.74), 9.76 (95% CI: 9.25-10.26), and 10.15 (95% CI: 9.37-10.92) m/s, respectively, in subjects with apnea-hypopnea index <5, 5-14.9, and ≥15 events/h.

CONCLUSIONS

In a community-based sample of middle aged and older men and women, sleep-disordered breathing was associated with increased carotid-femoral pulse wave velocity, a strong predictor of cardiovascular risk.

Association of Central Versus Brachial Blood Pressure With Target-Organ Damage: Systematic Review and Meta-Analysis

Accumulating evidence suggests that central blood pressure (BP) may reflect the hemodynamic stress on target organs more accurately than brachial BP. A systematic review assessing the relationship of central versus brachial BP with preclinical target-organ damage was performed. Meta-analysis of cross-sectional data showed that central compared with brachial systolic BP was more closely associated with (1) left ventricular mass index (12 studies, n=6431; weighted age [SD], 49.9 [13.1] years; 51% hypertensives): pooled correlation coefficients r=0.30; 95% confidence interval (CI), 0.23-0.37 versus r=0.26; 95% CI, 0.19-0.33, respectively; P<0.01 for difference; (2) carotid intima-media thickness (7 studies, n=6136; weighted age, 55.6 [13.2] years; 48% hypertensives): r=0.27; 95% CI, 0.19-0.34 versus r=0.23; 95% CI, 0.16-0.30, respectively; P<0.01 for difference; (3) pulse-wave velocity (14 studies, n=3699; weighted age, 53.9 [13.3] years; 53% hypertensives): r=0.42; 95% CI, 0.37-0.47 versus r=0.39; 95% CI, 0.33-0.45, respectively; P<0.01 for difference. Four studies assessing urine albumin excretion (n=3718; weighted age, 56.4 [5] years; 69% hypertensives) reported similar correlations (P=not significant) with central (r=0.22; 95% CI, 0.14-0.29) and brachial systolic BP (r=0.22; 95% CI, 0.12-0.32). Similar findings were observed for central compared with brachial pulse pressure in terms of relationship with target-organ damage. Metaregression analyses did not reveal any significant effect of age. In conclusion, central compared with brachial BP seems to be more strongly associated with most of the investigated indices of preclinical organ damage.

Relationships between sleep apnea, cardiovascular disease risk factors, and aortic pulse wave velocity over 18 years: the Wisconsin Sleep Cohort

PURPOSE

The purpose of this study is to determine if apnea-hypopnea index (AHI) severity predicts future aortic pulse wave velocity (PWV) in the Wisconsin Sleep Cohort.

METHODS

Applanation tonometry was used to derive carotid-to-femoral PWV a mean of 18 years (standard deviation 4) after overnight polysomnography. Multivariable regression models were created to describe prospective associations between baseline AHI and future PWV.

RESULTS

The 618 adults were mean 65 (7) years old (55 % male) with a mean body mass index of 31 (7) kg/m(2) at the tonometry visit. Mean baseline AHI was 4.6 (9.7) events/h. In multiple linear regression models adjusted for age (β = 0.13/year, standard error [SE] = 0.01, p < 0.001) and sex, higher log10AHI (β = 0.43/events/h, SE = 0.18, p = 0.02) was associated with PWV. After adjustment for waist circumference (β = 0.01/cm, SE = 0.01, p = 0.05) and height, the association between baseline log10AHI and future PWV was not statistically significant (p = 0.11), although the association with age persisted unchanged. Addition of covariates such as smoking status (current smoker β = 0.66, SE = 0.22, p = 0.002), diabetes mellitus status (β = 2.89, SE = 0.59, p < 0.001), and systolic blood pressure (BP, β = 0.03/mmHg, SE = 0.01, p < 0.001) did not change the association. AHI did not interact with age or smoking status to predict PWV. A secondary analysis of nocturnal oxygen saturation parameters in 517 participants, 9 (2) years prior also did not show any significant relationships with future PWV.

CONCLUSIONS

The prospective association between AHI and PWV is confounded by body size and influenced by smoking, diabetes mellitus, and BP. Weight management, BP control, and smoking cessation may help prevent arterial stiffening associated with obstructive sleep apnea.

Arterial stiffness in adult patients after Fontan procedure

Objectives

Increased arterial stiffness is a risk factor of atherosclerosis and cardio-vascular complications. The aim of the study was to determine whether peripheral vascular function might be an early marker of impaired health status in patients with a single ventricle after Fontan procedure.

Methods and results

Twenty five consecutive adults (11 women and 14 men) aged 24.7 ± 6.2 years after the Fontan procedure and 25 sex, age and BMI match healthy volunteers underwent physical examination, blood analysis, transthoracic echocardiography and noninvasive assessment of aortic stiffness. Augmented pressure and Augmentation Index (AIx) were both significantly elevated in Fontan when compared to the controls (6,08 ± 0,7 vs. 2,0 ± 3,7; p = 0.002 and 17,01 ± 3,3 vs. 6,05 ± 11; p < 0.001, respectively). There were no differences in pulse wave velocity (PWV), mean blood pressure (BP), brachial pulse pressure (PP), central: systolic BP, diastolic BP and PP. In Fontan group we find negative correlation between PWV and SatO2 (r = −0.68; p = 0.04) and positive correlation with WBC (0.72; p = 0.72; p = 0.013), INR (0.81; p = 0.008), TNFα (r = 0.45; p = 0.04), and postoperative time (r = 0.77; p = 0.02). AIx correlates positively only with age at surgery (r = 0.45; p = 0.04). Bilirubin level correlates positively with brachial PP (r = 0.71; p = 0.02) and central PP (r = 0.68; p = 0.03).

The multivariate model showed that SatO2 (β = −0.44, p = 0.04) was the only independent predictor of PWV (R² = 0.32, p = 0.03).

Conclusion

Adult Fontan patients have an increased arterial stiffness assessed by a noninvasive technique. Low arterial oxygen saturation postoperative time, age at surgery, white blood cells, TNFα and bilirubin level are associated with arterial stiffening in these patients. The combination of blood parameters of the hepatic function and noninvasive measurements of arterial stiffness could be helpful in comprehensive care of patients with Fontan circulation.

Systematic review on noninvasive assessment of subclinical cardiovascular disease in obstructive sleep apnea: new kid on the block!

Patients with obstructive sleep apnea (OSA) have a high burden of cardiovascular disease (CVD) but a causal relationship between OSA and atherosclerotic CVD remains unclear. We systematically reviewed the literature analyzing the relationship. A review of the Medline database for studies noninvasively evaluating subclinical CVD in OSA was conducted. A total of fifty-two studies were included in this review. Across the studies the prevalence of atherosclerosis, as assessed by coronary artery calcification, carotid intima-media thickness, brachial artery flow-mediated dilation and pulse wave velocity was higher in patients with OSA and correlated with increasing severity and duration of OSA. This study shows OSA is an independent predictor of subclinical CVD as CVD is more likely to occur in patients with long standing and severe OSA. Further research is however necessary to identify specific OSA populations that would benefit from aggressive screening.

A conversion formula for comparing pulse oximeter desaturation rates obtained with different averaging times

Objective

The number of desaturations determined in recordings of pulse oximeter saturation (SpO₂) primarily depends on the time over which values are averaged. As the averaging time in pulse oximeters is not standardized, it varies considerably between centers. To make SpO₂ data comparable, it is thus desirable to have a formula that allows conversion between desaturation rates obtained using different averaging times for various desaturation levels and minimal durations.

Methods

Oxygen saturation was measured for 170 hours in 12 preterm infants with a mean number of 65 desaturations <90% per hour of arbitrary duration by using a pulse oximeter in a 2–4 s averaging mode. Using 7 different averaging times between 3 and 16 seconds, the raw red-to-infrared data were reprocessed to determine the number of desaturations (D). The whole procedure was carried out for 7 different minimal desaturation durations (≥1, ≥5, ≥10, ≥15, ≥20, ≥25, ≥30 s) below SpO₂ threshold values of 80%, 85% or 90% to finally reach a conversion formula. The formula was validated by splitting the infants into two groups of six children each and using one group each as a training set and the other one as a test set.

Results

Based on the linear relationship found between the logarithm of the desaturation rate and the logarithm of the averaging time, the conversion formula is: D₂ = D₁ (T₂/T₁)^c, where D₂ is the desaturation rate for the desired averaging time T₂, and D₁ is the desaturation rate for the original averaging time T₁, with the exponent c depending on the desaturation threshold and the minimal desaturation duration. The median error when applying this formula was 2.6%.

Conclusion

This formula enables the conversion of desaturation rates between different averaging times for various desaturation thresholds and minimal desaturation durations.

Profile of circulating cytokines: impact of OSA, obesity and acute cardiovascular events

Obstructive sleep apnea (OSA) is inducing oxidative stress and consequently promotes systemic inflammation and cardiovascular morbidity. The respective impact of obesity, sleep apnea and acute cardiovascular events on the profile of inflammatory cytokines has not been extensively evaluated. We examined the profile of circulating cytokines in a case-control study comparing nonobese or obese patients with or without sleep apnea and with or without an acute cardiovascular event. Patients were assessed by sleep studies and inflammatory (hs-CRP, Leptin, RANTES, MCP1, IL6, IL8, TNF-α) and anti-inflammatory (adiponectin, IL1-Ra) cytokines profile. A cardiovascular phenotyping was performed including carotid intima-media thickness, pulse wave velocity and 24h blood pressure monitoring. In comparison with patients without sleep apnea or without comorbidities, patients with the combination of an acute cardiovascular event and pre-existing sleep apnea showed a higher burden of systemic inflammation with significant increase in serum levels of hs-CRP, IL1-Ra, IL-8, IL-6, TNF-α, Rantes and sICAM. Rantes and sICAM serum levels were independently associated with AHI after an acute cardiovascular event. Serum levels of different inflammatory markers were significantly increased in patients with the combination of sleep apnea and an acute cardiovascular event. Since these biomarkers could be associated with worsened cardiovascular outcome, diagnosing and treating associated sleep apnea is potentially important in patients after an acute cardiovascular event.

Effects of sleep patterns and obesity on increases in blood pressure in a 5-year period: report from the Tucson Children's Assessment of Sleep Apnea Study

OBJECTIVES

To determine associations between body mass index and sleep on blood pressure in a 5-year period from childhood to adolescence.

STUDY DESIGN

Study consisted of a longitudinal, community-based sample of 334 children recruited at ages 6 through 11 years. Each participant underwent in-home polysomnography initially and then 5 years later. Individual systolic blood pressure (SBP) and diastolic blood pressure (DBP) were calculated at both points during wake periods and classified as hypertensive when SBP or DBP was ≥ 95th standardized percentiles for height and weight.

RESULTS

Hypertension was present in 3.6% of the sample at time one and increased to 4.2% 5 years later. Obesity prevalence increased from 15.0% to 19.5%. Normal changes in sleep architecture were observed in the sample. With random effects modeling, which controlled for age, sex, and ethnicity, change in obesity status and decrease in total sleep time were indicated to be associated with increases in SBP. Change in obesity status was also associated with increases in DBP in the 5-year period. A trend for sleep-disordered breathing to increase SBP was noted.

CONCLUSIONS

Increases in SBP and DBP were associated with increasing body mass index and decreased total sleep time in a 5-year period from childhood to adolescence.

Is obstructive sleep apnoea causally related to arterial stiffness? A critical review of the experimental evidence

Large elastic arteries and smaller muscular conduit arteries become stiffer with ageing, a process that is accelerated in the presence of cardiovascular disease (CVD). In recent years, numerous techniques have been developed to measure arterial stiffness, either in single vessels or in entire muscular arterial trees. These techniques have increasingly been shown to improve stratification of cardiovascular risk and risk reduction beyond that provided by conventional risk factors. Obstructive sleep apnoea (OSA) has been increasingly linked with excess cardiovascular morbidity and mortality however the mechanisms are still not well understood. Robustly designed studies have shown that treatment of OSA with nasal continuous positive airway pressure improves important intermediate risk factors for CVD including hypertension and endothelial function. More recently, there has been increased exploration of arterial stiffness in both cross-sectional and interventional studies in OSA patients. This review aims to give the reader a better understanding of the measurement and pathophysiology of arterial stiffness as well as providing an indication of how well a prognostic indicator are the various measures of arterial stiffness for hard cardiovascular endpoints. A critical appraisal is then provided of cross-sectional and interventional studies that have explored these same techniques in OSA populations.

A prospective randomized controlled trial of the effects of vitamin D supplementation on cardiovascular disease risk

Vitamin D (VitD) supplementation has been advocated for cardiovascular risk reduction; however, supporting data are sparse. The objective of this study was to determine whether VitD supplementation reduces cardiovascular risk. Subjects in this prospective, randomized, double-blind, placebo-controlled trial of post-menopausal women with serum 25-hydroxyvitamin D concentrations >10 and <60 ng/mL were randomized to Vitamin D3 2500 IU or placebo, daily for 4 months. Primary endpoints were changes in brachial artery flow-mediated vasodilation (FMD), carotid-femoral pulse wave velocity (PWV), and aortic augmentation index (AIx). The 114 subjects were mean (standard deviation) 63.9 (3.0) years old with a 25-hydroxyvitamin D level of 31.3 (10.6) ng/mL. Low VitD (<30 ng/mL) was present in 47% and was associated with higher body-mass index, systolic blood pressure, glucose, CRP, and lower FMD (all p<0.05). After 4 months, 25-hydroxyvitamin D levels increased by 15.7 (9.3) ng/mL on vitamin D3 vs. −0.2 (6.1) ng/mL on placebo (p<0.001). There were no significant differences between groups in changes in FMD (0.3 [3.4] vs. 0.3 [2.6] %, p = 0.77), PWV (0.00 [1.06] vs. 0.05 [0.92] m/s, p = 0.65), AIx (2.7 [6.3] vs. 0.9 [5.6] %, p = 0.10), or CRP (0.3 [1.9] vs. 0.3 [4.2] mg/L, p = 0.97). Multivariable models showed no significant interactions between treatment group and low VitD status (<30 ng/mL) for changes in FMD (p = 0.65), PWV (p = 0.93), AIx (p = 0.97), or CRP (p = 0.26).In conclusion, VitD supplementation did not improve endothelial function, arterial stiffness, or inflammation. These observations do not support use of VitD supplementation to reduce cardiovascular disease risk.

MR elastography of the in vivo abdominal aorta: a feasibility study for comparing aortic stiffness between hypertensives and normotensives

PURPOSE

To demonstrate feasibility of using MR elastography (MRE) to identify hypertensive changes in the abdominal aorta when compared with normotensives based on the stiffness measurements.

MATERIALS AND METHODS

MRE was performed on eight volunteers (four normotensives and four hypertensives) to measure the effective stiffness of the abdominal aorta. MRE wave images are directionally filtered and phase gradient analysis was performed to determine the stiffness of the aorta. Student's t-test was performed to determine significant difference in stiffness measurements between normotensives and hypertensives.

RESULTS

The normotensive group demonstrated a mean abdominal aortic stiffness of 3.7 ± 0.8 kPa, while the controlled-hypertensive demonstrated a mean abdominal aortic stiffness of 9.3 ± 1.9 kPa. MRE effective stiffness of abdominal aorta in hypertensives was significantly greater than that of normotensives with p = 0.02.

CONCLUSION

Feasibility of in vivo aortic MRE is demonstrated. Hypertensives have significantly higher aortic stiffness assessed through MRE than normotensives.

Relation between self-reported sleep duration and arterial stiffness: a cross-sectional study of middle-aged Japanese civil servants

OBJECTIVES

The aim of this study is to examine the relationship between self-reported sleep duration and arterial stiffness in a large-scale Japanese study.

DESIGN

Cross-sectional study.

SETTING

Sapporo City, Hokkaido, Japan.

PARTICIPANTS

Local government employees aged 35-62 years, who underwent annual health checkups from April 2003 to March 2004. After excluding those with incomplete data, data from 4,268 employees (males: 3,410) participants were analyzed.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Brachial-ankle pulse-wave velocity (baPWV) was investigated as an indicator of arterial stiffness. We used a self-administered questionnaire, which included items on daily sleep duration, lifestyle factors, and occupational factors. Sleep duration was classified into 5 categories; " ≤ 5 h," "6 h," "7 h," "8 h," and " ≥ 9 h." Results of multiple linear regression analysis after fully adjusting the model revealed that subjects with ≥ 9 h of daily sleep had significantly elevated baPWV values compared with the reference group with 7 h of sleep. Stratified analyses by sex showed that there was a significant association among male subjects only.

CONCLUSIONS

Daily sleep duration ≥ 9 h was found to be associated with elevated values of baPWV. This suggests that there is an association between long sleep duration and arterial stiffness.