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Blood pressure (BP) fluctuates throughout the day. The pattern it follows represents one of the most important circadian rhythms in the human body. For example, morning BP surge has been suggested as a potential risk factor for cardiovascular events occurring in the morning, but the accurate quantification of this phenomenon remains a challenge. Here, we outline a novel method to quantify morning surge. We demonstrate how the most commonly used method to model 24-hour BP, the single cosinor approach, can be extended to a multiple-component cosinor random-effects model. We outline how this model can be used to obtain a measure of morning BP surge by obtaining derivatives of the model fit. The model is compared with a functional principal component analysis that determines the main components of variability in the data. Data from the Mitchelstown Study, a population-based study of Irish adults (n = 2047), were used where a subsample (1207) underwent 24-hour ambulatory blood pressure monitoring. We demonstrate that our 2-component model provided a significant improvement in fit compared with a single model and a similar fit to a more complex model captured by b-splines using functional principal component analysis. The estimate of the average maximum slope was 2.857 mmHg/30 min (bootstrap estimates; 95% CI: 2.855-2.858 mmHg/30 min). Simulation results allowed us to quantify the between-individual SD in maximum slopes, which was 1.02 mmHg/30 min. By obtaining derivatives we have demonstrated a novel approach to quantify morning BP surge and its variation between individuals. This is the first demonstration of cosinor approach to obtain a measure of morning surge., (Copyright © 2018 John Wiley & Sons, Ltd.)

Introduction: The aim of this study was to examine the association of night-time systolic blood pressure (BP) with subclinical cardiac dysfunction measured by global longitudinal strain (GLS) and subclinical vascular damage measured by carotid intima-media thickness (CIMT) and carotid plaques., Methods: GLS was measured by speckle-tracking analysis of echocardiogram images. CIMT was measured at the distal 1 cm of the common carotid artery. The presence of carotid plaques was recorded. Philips QLAB cardiac and vascular ultrasound quantification software was used for analysis. The association of night-time systolic BP with GLS, CIMT and carotid plaques was assessed using linear and logistic regression., Results: Fifty (response rate 63%) individuals took part in this study. In univariable models, night-time systolic BP was significantly associated with GLS [β coefficient 0.85 for every 10 mmHg increase, 95% confidence interval (CI): 0.3-1.4] and carotid plaques (odds ratio 1.9 for every 10 mmHg increase, 95% CI: 1.1-3.2). Univariable analysis of daytime systolic BP did not show any statistically significant associations. In age-adjusted and sex-adjusted models, the association for night-time systolic BP and GLS remained significant (β coefficient 0.68 for every 10 mmHg increase, 95% CI: 0.1-1.3). The association for carotid plaques was no longer statistically significant. In multivariable models, findings were diminished., Discussion: Our results suggest a trend towards an association between night-time systolic BP and subclinical cardiac and vascular disease. When assessing ambulatory blood pressure monitoring results, the absolute night-time systolic BP seems to be a better prognostic parameter than daytime systolic BP, but ultimately a large randomised controlled trial involving chronotherapy is necessary to fully address this.

Long-term blood pressure variability (BPV) has been associated with cardiovascular events but the prognostic significance of short-term BPV remains uncertain, including its influence on the presence of target-organ damage, specifically left-ventricular hypertrophy. A meta-analysis exploring the correlation between short-term BPV and left-ventricular mass index was performed. Studies were identified by systematic searches in Pubmed and EMBASE. Any summary measure of short-term BPV obtained from ambulatory blood pressure monitoring was included. Twelve studies were included. Average real variability (ARV), s.d., weighted s.d. and coefficient of variation across 24 h/day/night periods were identified as measures of variability. Meta-analysis showed the pooled subgroup correlation coefficients of LVMI with 24 h systolic blood pressure (SBP) s.d., day SBP s.d., weighted s.d. SBP and 24 h ARV SBP were 0.22 (95% confidence interval (CI): 0.12-0.31), 0.19 (95% CI: 0.15-0.25), 0.23 (95% CI: 0.13-0.33), 0.37 (95% CI: 0.01-0.65), respectively. This meta-analysis suggests there is a weak positive correlation, between BPV and LVMI.

Blood pressure variability (BPV) has been associated with cardiovascular events; however, the prognostic significance of short-term BPV remains uncertain. As uncertainty also remains as to which measure of variability most accurately describes short-term BPV, this study explores different indices and investigates their relationship with subclinical target organ damage (TOD). We used data from the Mitchelstown Study, a cross-sectional study of Irish adults aged 47-73 years (n=2047). A subsample (1207) underwent 24-h ambulatory BP monitoring (ABPM). As measures of short-term BPV, we estimated the s.d., weighted s.d. (wSD), coefficient of variation (CV) and average real variability (ARV). TOD was documented by microalbuminuria and electrocardiogram (ECG) left ventricular hypertrophy (LVH). There was no association found between any measure of BPV and LVH in both unadjusted and fully adjusted logistic regression models. Similar analysis found that ARV (24 h, day and night), s.d. (day and night) and wSD were all univariately associated with microalbuminuria and remained associated after adjustment for age, gender, smoking, body mass index (BMI), diabetes and antihypertensive treatment. However, when the models were further adjusted for the mean BP the association did not persist for all indices. Our findings illustrate choosing the appropriate summary measure, which accurately captures that short-term BPV is difficult. Despite discrepancies in values between the different measures, there was no association between any indexes of variability with TOD measures after adjustment for the mean BP.

Background: The prognostic significance of abnormal circadian blood pressure (BP) patterns is well established. Research to date has focused on both nocturnal dipping and absolute night-time BP levels; however, which of these variables should be the primary target for therapy remains unclear. The aim of this study is to determine whether dipping status or absolute night-time BP levels have a stronger association with subclinical target organ damage (TOD)., Methods: The Mitchelstown Cohort was established to examine cardiovascular health in an adult population sample recruited from primary care. Night-time BP was categorized by dipping status. Subclinical TOD was defined as Cornell Product left ventricular hypertrophy (LVH) voltage criteria on ECG and urine albumin : creatinine ratio (ACR) at least 1.1 mg/mmol. Multivariable logistic regression analysis was used to assess the association between night-time BP and TOD., Results: Of 2047 participants, 1207 (response rate 59%), underwent 24-h ambulatory BP monitoring. We excluded 161 studies due to incomplete data. Of 1046 participants, 178 (17%) had evidence of TOD. Each 10-mmHg rise in night-time SBP increased the odds of TOD. Odds ratio (OR) ACR at least 1.1 mg/mmol 1.5 [95% confidence interval (95% CI) 1.2-1.8] and OR LVH 1.4 (95% CI 1.1-1.8)., Conclusion: Absolute BP level rather than dipping status may be a superior early marker of risk associated with night-time BP. Interventional studies are required to determine whether there is a benefit in specifically targeting absolute night-time BP levels to prevent clinically important outcomes.

Isolated nocturnal hypertension (INH) is associated with greater mortality and cardiovascular events. Subclinical target organ damage (TOD) is a prognostic marker for cardiovascular events. Our objective is to systematically summarize evidence on the association between INH and subclinical TOD. Observational population studies were considered. INH was defined as nighttime blood pressure (BP) ⩾120 and/or 70 mm Hg with daytime BP <135/85 mm Hg. We systematically searched Pubmed, EMBASE and the Cochrane Library. Abstracts were reviewed by two assessors. Potentially eligible articles were compared with inclusion criteria. The search yielded 954 titles, 13 abstracts were selected for review and four articles fulfilled inclusion criteria. INH was associated with higher ambulatory arterial stiffness index (0.4 unit vs. 0.35 unit, P<0.05), pulse wave velocity (16.2 m s(-1) vs. 14.7 m s(-1), P<0.05), central (140.4% vs. 134.0%, P<0.05) and peripheral (82.6% vs. 76.5%, P<0.01) augmentation index in a Chinese study. In the same population there was no association with left ventricular hypertrophy documented by electrocardiogram. INH was not associated with increased arterial stiffness or left venticular mass index in a Swedish study. An American study demonstrated higher left ventricular mass (152.46 g vs. 136.16 g, P=0.01) and greater odds of left ventricular hypertrophy (odds ratio 3.03, 95% confidence interval 1.02-9.05) in unadjusted analysis. There was no association with proteinuria. Evidence is inconclusive regarding the association between INH and subclinical TOD. Future research should focus on trying to elucidate the mechanisms that generate INH and contribute to the higher mortality associated with this BP pattern.

Background: The Dietary Approaches to Stop Hypertension (DASH) Trial provides critical data on the impact of a specific diet pattern (low in salt, fat, and processed foods and high in fruit and vegetables) on blood pressure (BP). The effect of compliance with a DASH-type diet on BP in a general population sample is less well defined. We studied associations between a DASH style diet and BP., Methods: We used cross-sectional data from a study of men and women aged 47-73 years (n = 2,047). Participants completed a physical examination that included 3 standardized clinical BP recordings. A subsample (n = 1,187) had ambulatory BP measurements (ABPM) taken. Diet was assessed using a DASH dietary score constructed from a standard Food Frequency Questionnaire. Lower scores indicated less healthy diets. Hypertension was defined as clinic BP ≥ 140/90 mm Hg on medication or as 24-hour ABPM ≥ 130/80 mmHg., Results: Inverse associations were evident between DASH and systolic BP (SBP). There was a difference in clinic SBP of 7.5 mm Hg and 5.1 mm Hg and a difference in ABPM SBP of 6.3mm Hg and 5.4mm Hg in men and women, respectively, between the highest and lowest DASH quintiles. In fully adjusted multivariable regression analysis, DASH score was inversely associated with SBP. Clear population differences in SBP were evident across DASH quintiles., Conclusions: The observed associations indicate that the findings are consistent with the hypothesis that adherence to DASH-equivalent diet can reduce BP at the population level. Public policy promoting a DASH-style healthy diet could have a significant impact on population health by reducing average BP in the population., (© American Journal of Hypertension, Ltd 2013. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: White matter hyperintensities may contribute to depression by disrupting neural connections among brain regions that regulate mood. Orthostatic hypotension (OH) may be a risk factor for white matter hyperintensities and accumulating evidence, although limited suggests it may play a role in the development of late-life depression. The aim of this study was to examine the relationship between an oscillometric measure of orthostatic hypotension and depression in population based sample of older adults., Methods: We analysed data on adults aged 60 and over from the first wave of The Irish Longitudinal Study on Ageing (TILDA). Depression was assessed using the Center for Epidemiologic Studies--Depression (CES-D) scale and OH was assessed by a sit-to-stand orthostatic stress test; two seated blood pressure measurements were followed by a single standing blood pressure measurement. Participants self reported whether they felt dizzy, light-headed or unsteady on standing., Results: Participants with symptomatic OH (SOH, n=20) had the highest mean CES-D score (mean 8.6, SE 1.6) when compared to participants with asymptomatic OH (AOH) (mean 5.6, SE .48) and participants with no OH (mean 5.2, SE .14) and this difference was significant for both comparisons (p<0.001). Linear regression analysis adjusted for socio-demographic and clinical characteristics showed that SOH was associated with higher CES-D scores (unstandardised B coefficient = 2.24; 95% CI .301 - 4.79; p =0.05) compared to participants without OH. AOH was not associated with higher CES-D scores (unstandardised B coefficient =.162; 95% CI -.681, 1.00; p= 0.70)., Conclusions: Symptomatic orthostatic hypotension is associated with depression in older adults and needs to be considered in studies examining the relationship between vascular disease and depression in older adults.