Metabolic syndrome is associated with and predicted by resting heart rate: a cross-sectional and longitudinal study

Modifications of long-term heart rate variability produced in an experimental model of diet-induced metabolic syndrome

Metabolic syndrome (MetS) has been linked to a higher prevalence of cardiac arrhythmias, the most frequent being atrial fibrillation, but the mechanisms are not well understood. One possible underlying mechanism may be an abnormal modulation of autonomic nervous system activity, which can be quantified by analysing heart rate variability (HRV). Our aim was to investigate the modifications of long-term HRV in an experimental model of diet-induced MetS to identify the early changes in HRV and the link between autonomic dysregulation and MetS components. NZW rabbits were randomly assigned to control (n = 10) or MetS (n = 10) groups, fed 28 weeks with high-fat, high-sucrose diet. 24-hour recordings were used to analyse HRV at week 28 using time-domain, frequency-domain and nonlinear analyses. Time-domain analysis showed a decrease in RR interval and triangular index (Ti). In the frequency domain, we found a decrease in the low frequency band. Nonlinear analyses showed a decrease in DFA-α1 and DFA-α2 (detrended fluctuations analysis) and maximum multiscale entropy. The strongest association between HRV parameters and markers of MetS was found between Ti and mean arterial pressure, and Ti and left atrial diameter, which could point towards the initial changes induced by the autonomic imbalance in MetS.

Childhood maltreatment predicts physical health in college students

Objective: Childhood maltreatment (CM) is associated with physical health problems throughout the lifespan, yet more research is needed regarding the trajectory of health problems (e.g., onset of health risk indicators) in young adults. The current study examined whether college students self-reporting higher levels of CM exhibited poorer physical health outcomes. Method: Young adults in college (N = 100) completed a physical health assessment (heart rate, body mass index (BMI), blood pressure, blood sugar, waist circumference), self-reported measures of health (symptoms of illness), and CM during spring semester 2018. Results: CM scores predicted higher heart rate and increased symptoms of illness. Females with maltreatment history presented higher levels of obesity and more metabolic syndrome conditions than their peers. Conclusions: Findings support the importance of examining the trajectory of CM to chronic disease, as health risk indicators are present in young adults.

Comparative Analysis of Resting Heart Rate Measurement at Multiple Instances in a Single Day

Resting Heart Rate (RHR) is used as an indicator of cardiovascular health and overall fitness. Clinically, RHR is measured from beat-to-beat heart rate data during the day when the body is at rest (RHR_rest), typically for ≥ 5 minutes. In this paper, we have compared the RHR measurements done at multiple instances in a single day namely, [Formula: see text], RHR immediately after waking up (RHR_morning) and RHR during sleep (RHR_sleep). The significance of measuring RHR_sleep and why it can be used as a potential replacement for the conventional methods is analysed through an experimental study in this paper. The results obtained using the proposed method stands out in terms of repeatability. RHR measurements were taken for 3 instances on a single day for 9 subjects on 5 alternate workdays. A comparative analysis was performed by measuring the repeatability coefficient (RC) and Standard Deviation (SD) on the RHR measurements taken during multiple instances for each subject separately. The average RC and SD over the 5 alternate workdays was 5 bpm and SD was 2 bpm for RHR_slep. For RHR_rest and RHR_morning, the average RC was 12 bpm and 11 bpm and the average SD was 5 bpm and 4 bpm respectively, which is comparatively higher. Hence this method can be potentially adopted instead of the conventional methods as the RHRsleep parameter is more reliable and precise due to its repeatable nature.

A High-Protein and Low-Glycemic Formula Diet Improves Blood Pressure and Other Hemodynamic Parameters in High-Risk Individuals

Low-caloric formula diets can improve hemodynamic parameters of patients with type 2 diabetes. We, therefore, hypothesized that persons with overweight or obesity can benefit from a high-protein, low-glycemic but moderate-caloric formula diet. This post-hoc analysis of the Almased Concept against Overweight and Obesity and Related Health Risk- (ACOORH) trial investigated the impact of a lifestyle intervention combined with a formula diet (INT, n = 308) compared to a control group with lifestyle intervention alone (CON, n = 155) on hemodynamic parameters (systolic and diastolic blood pressure (SBP, DBP), resting heart rate (HR), and pulse wave velocity (PWV)) in high-risk individuals with prehypertension or hypertension. INT replaced meals during the first 6 months (1 week: 3 meals/day; 2−4 weeks: 2 meals/day; 5−26 weeks: 1 meal/day). Study duration was 12 months. From the starting cohort, 304 (68.3%, INT: n = 216; CON: n = 101) participants had a complete dataset. Compared to CON, INT significantly reduced more SBP (−7.3 mmHg 95% CI [−9.2; −5.3] vs. −3.3 mmHg [−5.9; −0.8], p < 0.049) and DBP (−3.7 mmHg [−4.9; −2.5] vs. −1.4 mmHg [−3.1; 0.2], p < 0.028) after 12 months. Compared to CON, INT showed a pronounced reduction in resting HR and PWV after 6 months but both lost significance after 12 months. Changes in SBP, DBP, and PWV were significantly associated positively with changes in body weight and fat mass (all p < 0.05) and resting HR correlated positively with fasting insulin (p < 0.001) after 12 months. Combining a lifestyle intervention with a high-protein and low-glycemic formula diet improves hemodynamic parameters to a greater extent than lifestyle intervention alone in high-risk individuals with overweight and obesity.

Conventional and Bidirectional Genetic Evidence on Resting Heart Rate and Cardiometabolic Traits

CONTEXT

Observational studies have suggested that higher resting heart rate (RHR) may be associated with increased cardiometabolic risk. However, causal associations are not fully understood.

OBJECTIVE

We aimed to examine the direction, strength, and causality of the associations of RHR with cardiometabolic traits.

METHODS

We assessed the strength of associations between measured RHR and cardiometabolic traits in 506 211 and 372 452 participants from China Kadoorie Biobank (CKB) and UK Biobank (UKB). Mendelian randomization (MR) analyses were used to make causal inferences in 99 228 and 371 508 participants from CKB and UKB, respectively.

RESULTS

We identified significant directionally concordant observational associations between RHR and higher total cholesterol, triglycerides (TG), low-density lipoprotein, C-reactive protein (CRP), glucose, body mass index, waist-hip ratio (WHR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) after the Bonferroni correction. MR analyses showed that 10 beat/min higher genetically predicted RHR was trans-ethnically associated with a higher DBP (beta 2.059 [95% CI 1.544, 2.574] mmHg in CKB; 2.037 [1.845, 2.229] mmHg in UKB), higher CRP (0.180 [0.057, 0.303] log mg/L in CKB; 0.154 [0.134, 0.174] log mg/L in UKB), higher TG (0.052 [-0.009, 0.113] log mmol/L in CKB; 0.020 [0.010, 0.030] log mmol/L in UKB) and higher WHR (0.218 [-0.033, 0.469] % in CKB; 0.225 [0.111, 0.339] % in UKB). In the opposite direction, higher genetically predicted SBP, TG, glucose, and WHR, and lower high-density lipoprotein, were associated with elevated RHR.

CONCLUSION

Our large-scale analyses provide causal evidence for associations between RHR and cardiometabolic traits, highlighting the importance of monitoring heat rate as a means of alleviating the adverse effects of metabolic disorders.

Effect of Probiotics Supplementation on Heart Rate: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Background and Aims

Probiotics consumption lowers the risk of cardiovascular disease, but whether it affects heart rate (HR) remains controversial. Therefore, our study aimed to assess the chronotropic effects of probiotics on heartbeat via a meta-analysis of randomized clinical trials.

Methods

Relevant studies were identified by searching PubMed, Cochrane library, and Clinical Trials databases up to October 2021. Either a fixed-effects or a random-effects model was used to calculate the pooled effect sizes and 95% confidence intervals (CIs).

Results

This meta-analysis included 13 studies involving 16 interventional trial arms and 931 participants according to inclusion criteria. The overall pooled estimate showed that probiotics supplementation had a slight, but no significant reduction of 0.28 bpm (95% CI: −1.17, 0.60) on HR. Relatively high heterogeneity was observed among included trials (I² = 80.8%, P heterogeneity < 0.001). Subgroup analysis displayed that probiotics supplementation significantly reduced HR by 2.94 bpm (95% CI: −5.06, −0.82) among participants with baseline HR ≥ 75 bpm, by 1.17 bpm (95% CI: −2.34, −0.00) with probiotics dose ≥1 × 10¹⁰ CFU/day, and by 1.43 bpm (95% CI: −2.69, −0.17) with multiple-strain intervention. Meta-regression analysis showed that baseline HR was a major potential effect modifier of probiotics supplementation on lowering HR.

Conclusion

Hitherto, the overall evidence in the literature was insufficient to support the notion that probiotics supplementation has a class effect on HR reduction. However, in subgroup analysis, probiotics reduced HR significantly in those who had higher baseline HR, received a higher dose or multiple strains of probiotics.

Association between Cardiorespiratory Fitness and Metabolic Syndrome in Korean Older Adults

Background: Little is known about the relationship between non-exercise-based estimation of cardiorespiratory fitness (eCRF) and metabolic syndrome (MetS) in Korea. The current study examined the prognostic role of eCRF in the risk stratification of MetS in a representative sample of Korean older adults (1822 men and 3069 women). Methods: The data used in the current study were extracted from the Korea National Health and Nutrition Examination Surveys IV and V. eCRF was obtained using a previously validated algorithm. MetS was defined according to the National Cholesterol Education Program definition with the acceptance of a Korean-specific waist circumference cutoff point. Results: Lower eCRF was significantly correlated with abnormalities in several components of MetS, including abdominal obesity, elevated glucose, elevated triglycerides, and decreased high-density lipoprotein cholesterol. Furthermore, there was an inverse linear relationship between MetS prevalence and eCRF levels; higher eCRF was significantly and independently associated with lower prevalence of MetS. Conclusion: The current findings suggest that eCRF can be adopted as a prognostic measure in determining the risk for MetS for elderly persons.

Resting heart rate is associated with the risk of metabolic syndrome and its components among Dong adults in southwest China: Cross-sectional findings of the China Multi-Ethnic Cohort Study

AIMS

High resting heart rate (RHR), one abnormal manifestation of autonomic nervous system, is associated with metabolic disorders. However, the association between RHR and metabolic syndrome (MetS) and its components remains controversial. We aimed to explore the link between these two parameters.

MATERIALS AND METHODS

The study included 6589 Dong adults (1434 cases of MetS) from the cross-sectional survey of the China Multi-Ethnic Cohort Study. Logistic regression model was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) and assess the association between RHR and MetS, clustered metabolic risk, and MetS components. Restricted cubic splines model was used to evaluate the dose response association.

RESULTS

A positive association existed between RHR and MetS, and people in the highest RHR quartile had a higher MetS risk (OR 1.75 [95% CI 1.42-2.15]) than those in the lowest quartile. The clustered metabolic risk associated with RHR (p < 0.05). Furthermore, RHR was related to elevated blood pressure (BP), elevated triglycerides (TG) and elevated fasting plasma glucose (FPG); the ORs (95% CIs) for the highest versus lowest RHR quartile were 2.06 (1.75-2.43), 1.37 (1.17-1.62) and 2.53 (2.04-3.14), respectively. Similar results were found in sensitivity and subgroup analyses. Also, non-linear dose response association existed between RHR and MetS and elevated levels of BP, TG and FPG (p < 0.001).

CONCLUSIONS

RHR was related to increased risk of MetS, three MetS components (elevated BP, elevated TG and elevated FPG) and the clustered metabolic risk. RHR may be a useful indicator for MetS.

Tale of two kinases: Protein kinase A and Ca2+/calmodulin-dependent protein kinase II in pre-diabetic cardiomyopathy

Metabolic syndrome is a pre-diabetic state characterized by several biochemical and physiological alterations, including insulin resistance, visceral fat accumulation, and dyslipidemias, which increase the risk for developing cardiovascular disease. Metabolic syndrome is associated with augmented sympathetic tone, which could account for the etiology of pre-diabetic cardiomyopathy. This review summarizes the current knowledge of the pathophysiological consequences of enhanced and sustained β-adrenergic response in pre-diabetes, focusing on cardiac dysfunction reported in diet-induced experimental models of pre-diabetic cardiomyopathy. The research reviewed indicates that both protein kinase A and Ca²⁺/calmodulin-dependent protein kinase II play important roles in functional responses mediated by β₁-adrenoceptors; therefore, alterations in the expression or function of these kinases can be deleterious. This review also outlines recent information on the role of protein kinase A and Ca²⁺/calmodulin-dependent protein kinase II in abnormal Ca²⁺ handling by cardiomyocytes from diet-induced models of pre-diabetic cardiomyopathy.

Automatic Artery/Vein Classification Using a Vessel-Constraint Network for Multicenter Fundus Images

Retinal blood vessel morphological abnormalities are generally associated with cardiovascular, cerebrovascular, and systemic diseases, automatic artery/vein (A/V) classification is particularly important for medical image analysis and clinical decision making. However, the current method still has some limitations in A/V classification, especially the blood vessel edge and end error problems caused by the single scale and the blurred boundary of the A/V. To alleviate these problems, in this work, we propose a vessel-constraint network (VC-Net) that utilizes the information of vessel distribution and edge to enhance A/V classification, which is a high-precision A/V classification model based on data fusion. Particularly, the VC-Net introduces a vessel-constraint (VC) module that combines local and global vessel information to generate a weight map to constrain the A/V features, which suppresses the background-prone features and enhances the edge and end features of blood vessels. In addition, the VC-Net employs a multiscale feature (MSF) module to extract blood vessel information with different scales to improve the feature extraction capability and robustness of the model. And the VC-Net can get vessel segmentation results simultaneously. The proposed method is tested on publicly available fundus image datasets with different scales, namely, DRIVE, LES, and HRF, and validated on two newly created multicenter datasets: Tongren and Kailuan. We achieve a balance accuracy of 0.9554 and F1 scores of 0.7616 and 0.7971 for the arteries and veins, respectively, on the DRIVE dataset. The experimental results prove that the proposed model achieves competitive performance in A/V classification and vessel segmentation tasks compared with state-of-the-art methods. Finally, we test the Kailuan dataset with other trained fusion datasets, the results also show good robustness. To promote research in this area, the Tongren dataset and source code will be made publicly available. The dataset and code will be made available at https://github.com/huawang123/VC-Net.

Autonomic Imbalance and Risk of Dementia and Stroke: The Framingham Study

Background and Purpose

The autonomic nervous system has been implicated in stroke and dementia pathophysiology. High resting heart rate and low heart rate variability indicate the effect of autonomic imbalance on the heart. We examined the associations of resting heart rate and heart rate variability with incident stroke and dementia in a community-based cohort of middle- and old-aged adults.

Methods

The study sample included 1581 participants aged >60 years and 3271 participants aged >45 years evaluated for incident dementia and stroke, respectively, who participated in the Framingham Offspring cohort third (1983–1987) examination and had follow-up for neurology events after the seventh (1998–2001) examination. Heart rate variability was assessed through the standard deviation (SD) of normal-to-normal RR intervals and the root mean square of successive differences between normal heartbeats from 2-hour Holter monitor. Participants were followed-up for stroke and dementia incidence from exam 7 to a maximum of 10 years. Cox regression models were used to assess the link of resting heart rate and heart rate variability with stroke and dementia risk while adjusting for potential confounders, and interactions with age and sex were assessed.

Results

Of the dementia (mean age, 55±6 years, 46% men) and stroke (mean age, 48±9 years, 46% men) samples, 133 and 127 developed dementia and stroke, respectively, during the follow-up. Overall, autonomic imbalance was not associated with dementia risk. However, age modified the associations such that SD of normal-to-normal intervals and root mean square of successive differences were associated with dementia risk in older people (hazard ratio [HR] [95% CI] per 1SD, 0.61 [0.38–0.99] and HR [95% CI] per 1SD, 0.34 [0.15–0.74], respectively). High resting heart rate was associated with increased stroke risk (HR [95% CI] per 10 bpm, 1.18 [1.01–1.39]), and high SD of normal-to-normal intervals was associated with lower stroke risk in men (HR [95% CI] per 1SD, 0.46 [0.26–0.79]) but not women (HR [95% CI] per 1SD, 1.25 [0.88–1.79]; P for interaction=0.003).

Conclusions

Some measures of cardiac autonomic imbalance may precede dementia and stroke occurrence, particularly in older ages and men, respectively.

Resting Heart Rate as a Cardiovascular Risk Factor in Hypertensive Patients: An Update

A large body of evidence has shown that resting heart rate (RHR) holds important prognostic information in several clinical conditions. In the majority of the general population studies, a graded association between RHR and mortality from all causes, cardiovascular (CV) disease, ischemic heart disease, and stroke has been observed. These associations appeared even stronger and more consistent in hypertensive patients. Studies performed with 24-hour ambulatory recording have shown that an elevated nighttime heart rate may confer an additional risk on top of office RHR. The mechanisms by which tachycardia alone or in association with sympathetic overactivity induces CV damage are well understood. Fast RHR is a strong predictor of future hypertension, metabolic disturbances, obesity, and diabetes. Several experimental lines of research point to high RHR as a main risk factor for the development of atherosclerosis, large artery stiffness, and CV disease. Elevated RHR is a common feature in patients with hypertension. Thus, there is a large segment of the hypertensive population that would benefit from a treatment able to decrease RHR. Improvement of unhealthy lifestyle should be the first goal in the management of the hypertensive patient with elevated RHR. Most clinical guidelines now recommend the use of combination therapies even in the initial treatment of hypertension. Although no results of clinical trials specifically designed to investigate the effect of RHR lowering in human beings without CV diseases are available, in hypertensive patients with high RHR a combination therapy including a cardiac slowing drug at optimized dose seems a sensible strategy. Tachycardia can be considered both as a marker of sympathetic overactivity and as a risk factor for cardiovascular events. In this sketch, the main cardiovascular and metabolic effects of increased sympathetic tone underlying high heart rate are shown. The link between tachycardia and cardiovascular events can be explained also by the direct hemodynamic action of heart rate on the arteries and the left ventricular (LV) wall.

Chronotropic effects and mechanisms of long-chain omega-3 polyunsaturated fatty acids on heartbeat: the latest insights

The roles of the resting heart rate (RHR) have been actively investigated and increasingly recognized in recent decades, because of the growing evidence that fast RHR is associated with and predicts the risk of developing cardiovascular and metabolic disorders, as well as all-cause mortality. Long-chain omega-3 polyunsaturated fatty acids (PUFAs) (eg, eicosapentaenoic acid and docosahexaenoic acid) have been shown to have chronotropic effects on heartbeat in both healthy people and patients with various disease conditions. The aims of this review are (1) to briefly summarize the importance of elevated RHR in disease pathogenesis and mortality; (2) to provide an update on the negative chronotropic effect of omega-3 PUFAs on the heart; (3) to highlight how omega-3 PUFAs regulate heart rate through the autonomic nervous system - a central control mechanism; and (4) to highlight how omega-3 PUFAs modulate the trans-membrane ionic channels in cardiomyocytes - a fundamental mechanism of cardiac automaticity. Eicosapentaenoic acid and docosahexaenoic acid are nutrients derived from some aquatic organisms, and they can also be converted from digested oily seeds and nuts of some terrestrial plants in the body. The consumption of omega-3 PUFAs for RHR reduction represents a lifestyle modification for risk factor management and promises nutritional benefits for public health improvement.

Reliability of bioimpedance and indirect calorimetry to evaluate resting metabolic rate in Brazilian women with metabolic syndrome

BACKGROUND AND AIMS

Precise evaluation of resting metabolic rate (RMR) is critical, especially for seniors in syndromes conditions. The study aimed to compare different methods and devices to evaluate the resting metabolic rate and assess them' reliability in Brazilian women with metabolic syndrome.

METHODS

A single-center prospective study with forty elderly postmenopausal women was performed to verify the reliability of indirect calorimetry (IC) versus Bioimpedance (BIA) on RMR fluctuations for an interval length of six months.

RESULTS

Measurements showed a high correlation between devices at baseline [BIA vs IC, intraclass correlation coefficient (ICC) = 0.906 (0.822-0.950)]. Surprisingly, a high correlation was kept between BIA and IC after six months [BIA vs. IC, ICC = 0.909 (0.829-0.952)]. The results suggest that both BIA and IC are excellent strategies to measure RMR in elderly postmenopausal women and with metabolic syndrome.

CONCLUSIONS

However, the BIA method presents greater convenience, optimizes patients' time, and does not require prolonged fasting to obtain good reliable results compared to IC.

Experimental dopaminergic neuron lesion at the area of the biological clock pacemaker, suprachiasmatic nuclei (SCN) induces metabolic syndrome in rats

BACKGROUND

The daily peak in dopaminergic neuronal activity at the area of the biological clock (hypothalamic suprachiasmatic nuclei [SCN]) is diminished in obese/insulin resistant vs lean/insulin sensitive animals. The impact of targeted lesioning of dopamine (DA) neurons specifically at the area surrounding (and that communicate with) the SCN (but not within the SCN itself) upon glucose metabolism, adipose and liver lipid gene expression, and cardiovascular biology in normal laboratory animals has not been investigated and was the focus of this study.

METHODS

Female Sprague-Dawley rats received either DA neuron neurotoxic lesion by bilateral intra-cannula injection of 6-hydroxydopamine (2-4 μg/side) or vehicle treatment at the area surrounding the SCN at 20 min post protriptyline ip injection (20 mg/kg) to protect against damage to noradrenergic and serotonergic neurons.

RESULTS

At 16 weeks post-lesion relative to vehicle treatment, peri-SCN area DA neuron lesioning increased weight gain (34.8%, P < 0.005), parametrial and retroperitoneal fat weight (45% and 90% respectively, P < 0.05), fasting plasma insulin, leptin and norepinephrine levels (180%, 71%, and 40% respectively, P < 0.05), glucose tolerance test area under the curve (AUC) insulin (112.5%, P < 0.05), and insulin resistance (44%-Matsuda Index, P < 0.05) without altering food consumption during the test period. Such lesion also induced the expression of several lipid synthesis genes in adipose and liver and the adipose lipolytic gene, hormone sensitive lipase in adipose (P < 0.05 for all). Liver monocyte chemoattractant protein 1 (a proinflammatory protein associated with metabolic syndrome) gene expression was also significantly elevated in peri-SCN area dopaminergic lesioned rats. Peri-SCN area dopaminergic neuron lesioned rats were also hypertensive (systolic BP rose from 157 ± 5 to 175 ± 5 mmHg, P < 0.01; diastolic BP rose from 109 ± 4 to 120 ± 3 mmHg, P < 0.05 and heart rate increase from 368 ± 12 to 406 ± 12 BPM, P < 0.05) and had elevated plasma norepinephrine levels (40% increased, P < 0.05) relative to controls.

CONCLUSIONS

These findings indicate that reduced dopaminergic neuronal activity in neurons at the area of and communicating with the SCN contributes significantly to increased sympathetic tone and the development of metabolic syndrome, without effect on feeding.

Heart rate as a predictor of cardiovascular risk

Heart rate is a parameter that is very easy to measure and is widely used both in clinic and during daily life activities. Its value gained more relevance with the evidence, in prospective studies and meta-analysis, of association between elevated heart rate values and diseases and outcomes.The increased knowledge of physiological mechanisms of heart rate control and the pathophysiological mechanisms responsible for its dysfunction allows to identify the cut-off value of normalcy providing info for non-pharmacological and pharmacological treatments to reduce the cardiovascular risk both in general population and in pathophysiological conditions. This paper overviews the knowledges of the role of resting heart rate as predictor of cardiovascular risk.

Association of resting heart rate with nonalcoholic fatty liver disease in postmenopausal women

Resting heart rate, a simple and useful indicator of autonomic function, and its imbalance has emerged as an independent predictor of cardio metabolic diseases. Nonalcoholic fatty liver disease (NAFLD) is increasingly being diagnosed worldwide and is strongly associated with the features of cardiometabolic diseases. This study aimed to examine the association between resting heart rate and NAFLD in postmenopausal women.The cross-sectional study included 1017 postmenopausal women aged ≥46 years, who attended a health examination program. Resting heart rate and NAFLD were measured in all subjects who underwent a medical examination. Resting heart rate quartiles were categorized as follows: Q1: 56 to 65, Q2: 66 to 71, Q3: 72 to 78, and Q4: 79 to 99 beats/min. The odds ratios and 95% confidence intervals for NAFLD were calculated after adjusting for confounding variables across resting heart rate quartiles using multiple logistic regression analysis.The prevalence of NAFLD increased with increasing resting heart rate quartiles: 28.2% for Q1, 31.5% for Q2, 33.4% for Q3, and 38.1% for Q4 (P < .001). Compared to the 1st quartile, the odds ratio (95% confidence intervals) of NAFLD in the 4th quartile of resting heart rates was 2.11 (1.17-3.42) after adjusting for age, body mass index, cigarette smoking, regular exercise, blood pressure, total cholesterol, triglyceride, aspartate aminotransferase, and alanine aminotransferase levels.Resting heart rate was positively associated with NAFLD in postmenopausal women, suggesting that it could be a useful additional measure to assess the risk for NAFLD in postmenopausal women.

Link Between Elevated Long-Term Resting Heart Rate Variability and Pulse Pressure Variability for All-Cause Mortality

Background

Elevated long‐term systolic blood pressure and resting heart rate (RHR) variability are suggested to amplify the risk of all‐cause mortality (ACM). However, the link between increased RHR and pulse pressure for ACM remained unclear.

Methods and Results

This study analyzed 46 751 individuals from Kailuan Cohort Study for the end outcome of ACM. A Cox regression model was used to estimate hazard ratios for death events. Kaplan‐Meier analysis was performed to study the differences in survival as stratified by the SD, coefficient of variation, and average real variability of RHR and pulse pressure quartiles. A total of 1667 deaths (<65 years of age=866/40351, ≥65 years of age=801/6400) were recorded over 4.97±0.69 years follow‐up. Participants under the age of 65 years in the third and fourth quartiles of pulse pressure SD had an independent increase in risk for ACM (hazard ratio [95% CI], 1.16 [1.06–1.28]; and 1.19 [1.05–1.35], respectively). Additionally, participants >65 years of age had a higher risk for ACM across quartiles of RHR‐SD. The hazard ratio (95% CI) for the subjects in quartiles 2, 3, and 4 were 1.81 (1.10–2.97), 2.31 (1.37–1.3.90), and 2.64 (1.63–4.29), respectively.

Conclusions

An elevated long‐term RHR variability combined with an increased pulse pressure variability or vice versa amplifies the risk of ACM.

Heart rate as cardiovascular risk factor

Heart rate is a parameter that is widely used by the general population as a marker of health. The availability of wearable electronic heart rate monitoring devices and use of specific apps are widely used both at rest and during daily life activities. Resting heart rate values gained more relevance with the evidence of association between elevated heart rate values at rest and diseases and adverse events. Also longitudinal studies demonstrated a clear association between increase in heart rate over time and cardiovascular and all-cause mortality. The increased knowledge of physiological mechanisms of heart rate control and the pathophysiological mechanisms responsible for its dysfunction allows identification of the cutoff value of normalcy. This information can be used to select non-pharmacological and pharmacological interventions to reduce the cardiovascular risk both in the general population and in patients with pathophysiological conditions. This review provides an overview of the current knowledge of resting heart rate as cardiovascular risk factor.

Circadian-timed quick-release bromocriptine lowers elevated resting heart rate in patients with type 2 diabetes mellitus

OBJECTIVE

Sympathetic nervous system (SNS) overactivity is a risk factor for insulin resistance and cardiovascular disease (CVD). We evaluated the impact of bromocriptine-QR, a dopamine-agonist antidiabetes medication, on elevated resting heart rate (RHR) (a marker of SNS overactivity in metabolic syndrome), blood pressure (BP) and the relationship between bromocriptine-QR's effects on RHR and HbA1c in type 2 diabetes subjects.

DESIGN AND SUBJECTS

RHR and BP changes were evaluated in this post hoc analysis of data from a randomized controlled trial in 1014 type 2 diabetes subjects randomized to bromocriptine-QR vs placebo added to standard therapy (diet ± ≤2 oral antidiabetes medications) for 24 weeks without concomitant antihypertensive or antidiabetes medication changes, stratified by baseline RHR (bRHR).

RESULTS

In subjects with bRHR ≥70 beats/min, bromocriptine-QR vs placebo reduced RHR by -3.4 beats/min and reduced BP (baseline 130/79; systolic, diastolic, mean arterial BP reductions [mm Hg]: -3.6 [P = .02], -1.9 [P = .05], -2.5 [P = .02]). RHR reductions increased with higher baseline HbA1c (bHbA1c) (-2.7 [P = .03], -5 [P = .002], -6.1 [P = .002] with bHbA1c ≤7, >7, ≥7.5%, respectively] in the bRHR ≥70 group and more so with bRHR ≥80 (-4.5 [P = .07], -7.8 [P = .015], -9.9 [P = .005]). Subjects with bRHR <70 had no significant change in RHR or BP. With bHbA1c ≥7.5%, %HbA1c reductions with bromocriptine-QR vs placebo were -0.50 (P = .04), -0.73 (P = .005) and -1.22 (P = .008) with bRHR <70, ≥70 and ≥80, respectively. With bRHR ≥70, the magnitude of bromocriptine-QR-induced RHR reduction was an independent predictor of bromocriptine-QR's HbA1c lowering effect.

CONCLUSION

Bromocriptine-QR lowers elevated RHR with concurrent decrease in BP and hyperglycaemia. These findings suggest a potential sympatholytic mechanism contributing to bromocriptine-QR's antidiabetes effect and potentially its previously demonstrated effect to reduce CVD events.

The Association of Metabolic Syndrome and Its Components with Electrocardiogram Parameters and Abnormalities Among an Iranian Rural Population: The Fasa PERSIAN Cohort Study

BACKGROUND

Metabolic syndrome (MetS) as a set of cardiac risk factors and its growing prevalence is one of the major concerns in different societies. In this study, we aimed to investigate the relationship between Mets and electrocardiogram (ECG) parameters and abnormalities as indicators for subclinical cardiovascular diseases (CVD).

METHODS

In this sub-analysis study, we used the data from Fasa PERSIAN Cohort Study which includes subjects age 35-70 years. Subjects with available ECG data included in the study (n=7002) and subjects with missing data on MetS components and non-sinus rhythm ECG were excluded (n=44). The MetS definition based on the Adult Treatment Panel (ATP) III guidelines and also a 12-lead ECG was obtained from all participants.

RESULTS

Our study population (n=6958) showed a mean age of 48.60±9.34 years and also 1656 (24.2%) subjects had MetS. Except for P duration, PR interval and S amplitude in men and P amplitude, S amplitude, Sokolow-Lyon Index, and QT interval in women, other ECG parameters differ significantly between subjects with and without Mets (P<0.05). Also among ECG abnormalities, prolonged P duration (≥120ms), QRS duration (≥100ms), and QTc interval (>450ms in male, >470ms in female) had a significant association with MetS in the total population. Waist circumferences (WC) showed the most count of significant relationship with ECG parameters in both genders. In males, WC more than ATP cut-points had significant associations with prolonged P and QRS duration, and also blood pressure (BP) had significant associations with prolonged P and QRS durations and QTc interval. In females, the MetS component except triglyceride had at least a significant relationship with prolonged P and/or QRS duration.

CONCLUSION

MetS and its component especially WC and BP were associated with ECG parameters and abnormalities. These associations with ECG as a marker of subclinical CVD showed the importance of MetS and each component in our population to monitor in the further longitudinal studies.

Vitamin D Status and Correlation with Glucose and Lipid Metabolism in Gansu Province, China

OBJECTIVE

To investigate the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels and blood glucose and lipid levels in people over 18 years of age in Gansu, China.

SUBJECTS AND METHODS

A total of 1928 volunteers (958 males and 970 females) were selected. The prevalence of abnormal glucose metabolism and lipid metabolism in the vitamin D deficiency group (<20 ng/mL) and the non-vitamin D deficiency group (≥20 ng/mL) were compared. The correlations between serum 25(OH)D and blood glucose and lipid were analyzed.

RESULTS

A total of 1681 patients had 25(OH)D deficiency, with an overall prevalence of 87.2% (82.9% in males and 91.4% in females). The levels of 25(OH)D in the diabetic group and the IGT/IFG group were significantly lower than that in the normal group. The level of 25(OH)D was significantly lower in the dyslipidemia group than that in the normal group, and was significantly lower in the fasting plasma glucose (FPG) ≥5.6 mmol/L group than that in the FPG <5.6 mmol/L group (p=0.002). The 25(OH)D level in the serum triglyceride (TG) ≥1.7 mmol/L group was significantly lower than that of the TG <1.7 mmol/L group (p=0.0274). The age, heart rate, TG, TC, FPG and H₂PG levels in the vitamin D deficiency group were significantly higher than those in the non-vitamin D deficiency group (p<0.05). The prevalence of FPG ≥5.6 mmol/L in the vitamin D deficiency group was higher than that in the non-vitamin D deficiency group (23.5% vs 16.6%, p=0.016). Multiple linear regression analysis suggested that serum 25(OH)D levels were independently correlated with gender, age, FPG, TG and heart rate (β=-0.218, -0.129, -0.075, β=-0.103, -0.058, all p<0.05).

CONCLUSION

The incidences of dyslipidemia and dysglycemia were higher in the vitamin D deficiency group. The vitamin D level was independently and negatively correlated with FPG and TC, but not with waist circumference, BMI and blood pressure.

Exercise capacity and body mass index - important predictors of change in resting heart rate

BACKGROUND

Resting heart rate (RHR) is an obtainable, inexpensive, non-invasive test, readily available on any medical document. RHR has been established as a risk factor for cardiovascular morbidity, is related to other cardiovascular risk factors, and may possibly predict them. Change in RHR over time (∆RHR) has been found to be a potential predictor of mortality.

METHODS

In this prospective study, RHR and ∆RHR were evaluated at baseline and over a period of 2.9 years during routine check-ups in 6683 subjects without known cardiovascular disease from the TAMCIS: Tel-Aviv Medical Center Inflammation Survey. Multiple linear regression analysis with three models was used to examine ∆RHR. The first model accounted for possible confounders by adjusting for age, sex and body mass index (BMI). The 2nd model included smoking status, baseline RHR, diastolic blood pressure (BP), dyslipidemia, high-density lipoprotein (HDL) and metabolic equivalents of task (MET), and in the last model the change in MET and change in BMI were added.

RESULTS

RHR decreased with age, even after adjustment for sex, BMI and MET. The mean change in RHR was - 1.1 beats/min between two consecutive visits, in both men and women. This ∆RHR was strongly correlated with baseline RHR, age, initial MET, and change occurring in MET and BMI (P < 0.001).

CONCLUSIONS

Our results highlight the need for examining individual patients' ∆RHR. Reinforcing that a positive ∆RHR is an indicator of poor adherence to a healthy lifestyle.

Resting heart rate is associated with metabolic syndrome and predicted 10-year risk of cardiovascular disease: a cross-sectional study

BACKGROUND

This study examined whether resting heart rate (RHR) was associated with metabolic syndrome (MetS) and the 10-year predicted risk of cardiovascular disease in a Chinese population.

METHODS

The associations of RHR with MetS and 10-year risk of atherosclerotic cardiovascular diseases (ASCVD) was examined in a cross-sectional study conducted in Shanghai, China (n = 9486).

RESULTS

Compared with individuals in the lowest RHR quintile (≤71 b.p.m.), those in the highest quintile (≥91 b.p.m.) had a higher prevalence of MetS (21.2% vs 32.6%, respectively; P < 0.001). Logistic regression analyses showed that the multivariate-adjusted odds ratio (OR) and 95% confidence interval (CI) for MetS was 1.13 (1.08-1.18) for each 10-b.p.m. increment of RHR (P < 0.0001). Furthermore, RHR was strongly associated with the prevalence of hypertension, high blood glucose, and dyslipidemia, but not with central obesity. A stronger association of RHR with MetS was observed among individuals aged <65 years, male, with a body mass index <24 kg/m² , without diabetes, hypertension, abnormal lipids, and insulin resistance than among their counterparts (P < 0.05 for all). A significantly higher 10-year risk for ASCVD was observed with each 10-b.p.m. increment in RHR in both men and women (ORs [95% CIs] 1.20 [1.07-1.33] and 1.28 [1.17-1.39], respectively; P_trend  = 0.002 and < 0.0001, respectively).

CONCLUSIONS

In this study, RHR was associated with a higher prevalence of MetS and elevated 10-year predicted risk of ASCVD in both Chinese men and women. Whether RHR may serve as an indicator for MetS among relatively healthy individuals requires further investigation.

Physical Activity Practice and Healthy Lifestyles Related to Resting Heart Rate in Health Sciences First-Year Students

The expression lifestyle describes a frame of expressed behaviors, usually in the form of patterns of consumption, that defines how an individual or social group fits into society. It presents as a focus of interest by researchers in this field, who classically favor the study of alcohol consumption, tobacco, eating habits, and physical activity. The aim of this study was to identify the relationship between physical activity and healthy lifestyles, especially in terms of eating habits, tobacco, alcohol consumption, resting habits, and resting heart rate (RHR) in Health Sciences first-year students. A total of 177 students of both genders participated, of whom 31 (17.5%) were male and 146 (82.5%) were female, with a mean age of 20.20 years, from 18 to 30 years. The data collection instrument used was the Healthy Lifestyle Questionnaire (EVS), using SPSS 21.0 for descriptive statistics and the Cronbach α to evaluate the internal consistency of the questionnaires. A level of significance was adopted with a margin of error of 5% for a probability of at least 95% using the Kolmogorov-Smirnov technique and Mann-Whitney test for comparisons between practitioners’ students and genders. The results obtained demonstrate more favorable results in all variables in students practicing physical activity with significant differences in eating habits and RHR. In terms of gender, there were significant differences in all variables except for eating habits. We conclude that students practicing physical activity present more favorable results in terms of lifestyles combined with lower RHR values, considered as positive factors in terms of quality of life.

Vitamin D deficiency is associated with dyslipidemia: a cross-sectional study in 3788 subjects

BACKGROUND

Previously we reported on severe vitamin D deficiency in a large-scale cohort in the Tangshan area in northern China. However, whether vitamin D deficiency is associated with cardiovascular risk factors has not been systematically examined in the cohort.

OBJECTIVE

We aimed to determine the correlation between serum vitamin D status and lipid levels in circulation via an observational study.

METHODS

Serum 25-hydroxyvitamin D (25[OH]D) was measured. Based on the measurement subjects were classified into quintiles. Dyslipidemia was defined as having one of the following: elevated serum total cholesterol, LDL cholesterol, triglycerides or decreased HDL cholesterol, under lipid-control treatment.

RESULTS

The study was conducted in a total of 3788 adults in northern China during their routine health examinations. When the highest quintile of the 25(OH)D level was set as reference, the risk of having dyslipidemia increased progressively across the highest to the lowest 25(OH)D with ORs of 1 (reference), 1.232 (95% CI, 1.005-1.509), 1.235 (95% CI, 1.007-1.513), 1.403 (95% CI, 1.143-1.735) and 1.494 (95% CI, 1.217-1.833), respectively (P_trend < .0001) after adjustment for age. This trend was unchanged after further adjustment for several potential confounders. In linear regression analysis, we found an inverse significant correlation between 25(OH)D and triglycerides (β coefficient = -0.077, p < .05) and LDL cholesterol (β coefficient = -0.245, p < .05), and positive correlation with HDL cholesterol (β coefficient = 0.038, p = .018).

CONCLUSION

Vitamin D deficiency is found to be associated with dyslipidemia in a cohort of 3788 subjects. Specifically, serum 25(OH)D is inversely correlated with LDL cholesterol and triglycerides levels, and positively correlated with HDL cholesterol level.

Habitual coffee intake reduces all-cause mortality by decreasing heart rate

It is well known that subjects with metabolic syndrome show an elevated resting heart rate. We previously reported that elevated heart rate was significantly related to all-cause mortality, and that coffee consumption was inversely associated with metabolic syndrome. We hypothesized that higher coffee consumption may decrease all-cause mortality by reducing resting heart rate. We performed a longitudinal epidemiological study in Tanushimaru (a cohort of the Seven Countries Study). A total of 1920 residents aged over 40 years received health checkups in 1999. We measured components of metabolic syndrome, and eating and drinking patterns were evaluated by a food frequency questionnaire. We followed up the participants annually for 15 years. During the follow-up period, 343 of the participants died. Of these, 102 subjects died of cancer, 48 of cerebro-cardiovascular diseases, and 44 of infectious diseases. Multivariate analyses revealed that higher coffee consumption was inversely associated with resting heart rate. Kaplan-Meier curves found lower mortality rates in the higher coffee consumption groups. In the lower coffee consumption groups, elevated hazard ratios of all-cause death were observed in the increased heart rate quintiles, whereas heart rate was not associated with all-cause death in the higher coffee consumption groups. These significant associations remained after further adjustment for confounders. This prospective study suggests that higher coffee consumption may have a protective effect against all-cause death due to reducing resting heart rate.

The Association between Resting Heart Rate and Urinary Albumin/Creatinine Ratio in Middle-Aged and Elderly Chinese Population: A Cross-Sectional Study

OBJECTIVE

In general population, resting heart rate (RHR) is associated with cardiovascular disease. However, its relation to chronic kidney disease (CKD) is debated. We therefore investigated the relationship between RHR and urinary albumin/creatinine ratio (UACR, an indicator of early kidney injury) in general population at different levels of blood pressure and blood glucose.

METHODS

We screened out 32,885 subjects from the REACTION study after excluding the subjects with primary kidney disease, heart disease, tumor history, related drug application, and important data loss. The whole group was divided into four groups (Q1: RHR ≤ 71, Q2: 72 ≤ RHR ≤ 78, Q3: 79 ≤ RHR ≤ 86, and Q4: 87 ≤ RHR) according to the quartile of average resting heart rate. The renal function was evaluated by UACR (divided by quartiles of all data in the center to which the subject belonged). Ordinary logistic regression was carried out to explore the association between RHR and UACR at diverse blood pressure and blood glucose levels.

RESULTS

The subjects with higher RHR quartile tend to have a higher UACR, even multifactors were adjusted. After stratifying the subjects according to blood pressure and blood glucose, the positive relationship between RHR and UACR remained in the subjects with normal blood pressure and normal glucose tolerance, while in the hypertension (SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg) group and the diabetic mellitus (FPG ≥ 7.0 mmol/L and/or PPG ≥ 11.1 mmol/L) group, the relationship disappeared. In the subjects without hypertension, compared with the Q1 group, the UACR is significant higher in the Q3 group (OR: 1.11) and the Q4 group (OR: 1.22). In the subjects with normal glucose tolerance (NGT), compared with the Q1 group, the UACR is significantly higher in the Q3 group (OR: 1.13) and the Q4 group (OR: 1.19).

CONCLUSIONS

The population with higher RHR tend to have a higher UACR in the normal blood pressure group and the normal glucose tolerance group.

Heart Rate and Bone Mineral Density in Older Women with Hypertension: Results from the Korea National Health and Nutritional Examination Survey

OBJECTIVES

To determine whether high heart rate is associated with low bone mineral density (BMD) in older women with hypertension.

DESIGN

Retrospective cohort study.

SETTING

Population-based study conducted in Korea (Korea National Health and Nutritional Examination Survey 2009-10).

PARTICIPANTS

Postmenopausal women aged 60 and older with hypertension (N=981) divided into 2 groups according to resting heart rate, with a cut-off value of 80 bpm, which has been found to be associated with osteoporosis.

MEASUREMENTS

BMD profiles and clinical and laboratory data were collected. Osteoporosis was defined as a T-score of -2.5 or less, according to World Health Organization criteria.

RESULTS

BMD was significantly lower in participants with a high heart rate, even after adjustment for age, diabetes mellitus, white blood cell count, and fasting glucose and triglyceride levels. The prevalence of osteoporosis was also significantly higher in those participants. In multivariate logistic regression analysis, the group with high heart rate was 1.7 times as likely (95% confidence interval=1.2-2.3) to have osteoporosis as those with a lower heart rate, independent of age, body mass index, comorbidities, and laboratory findings.

CONCLUSION

High heart rate is independently associated with lower BMD in older women with hypertension; proactive surveillance of BMD could be helpful when managing older women with hypertension and a high heart rate.

Heart rate as a predictor of cardiovascular risk

BACKGROUND

Heart rate (HR) is a predictor of cardiovascular, cerebrovascular and all-cause mortality in the general population, as well as in patients with cardio- and cerebrovascular diseases. We aimed to summarize current knowledge regarding the influence of HR on cardio- and cerebrovascular morbidity and mortality.

MATERIALS AND METHODS

PubMed, MEDLINE, Ovid and EMBASE databases were searched for large follow-up studies or meta-analysis published between January 1990 and September 2017 in the English language using the following keyword "heart rate," "resting heart rate," "mortality," "outcome," "hypertension," "heart failure," "ischaemic heart disease," "coronary heart disease" and "stroke."

RESULTS

The relationship between increased HR and cardio- and cerebrovascular morbidity and mortality has been reported in a large number of studies, and the results regarding this association are concurrent. This connection is generally stronger in men than in women. The increase in HR usually occurs in parallel with elevation of blood pressure and metabolic disturbances (insulin resistance, dyslipidaemia). However, even after adjustment for the most important cardiovascular risk factors, HR remained an independent predictor of adverse events in global population or in patients with cardio- and cerebrovascular diseases.

CONCLUSION

HR has an important negative effect on cardio- and cerebrovascular morbidity and mortality. Future longitudinal investigations should clarify HR significance and optimal HR reduction for primary and secondary prevention in cardio- and cerebrovascular events.

Effect of omega-3 long-chain polyunsaturated fatty acid supplementation on heart rate: a meta-analysis of randomized controlled trials

Background

Elevated resting heart rate (HR) has emerged as a new risk factor for all-cause and cardiovascular mortality. The effect of marine-derived omega-3 long-chain polyunsaturated fatty acid (n−3 LCPUFAs) supplementation on HR was investigated as an outcome in many clinical trials. The present study was to provide an updated meta-analysis on the HR-slowing effect of n−3 LCPUFAs, and to differentiate the chronotropic effect between eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Methods

PubMed and Cochrane databases were searched for relevant articles examining the effects of n−3 PUFAs on HR through May 2017. A random-effects model was used to generate the pooled effect sizes and 95% confidence intervals (CIs). The pooled effect sizes were presented as weighted mean differences (WMDs).

Results

A total of 51 randomized controlled trials (RCTs) with approximately 3000 participants were included in this meta-analysis. Compared to placebo, n−3 PUFA supplementation mildly but significantly reduced HR (−2.23 bpm; 95% CI: −3.07, −1.40 bpm). Moderate evidence of heterogeneity was observed among included trials (I² = 49.1%, P heterogeneity < 0.001). When DHA and EPA were separately administered, modest HR reduction was observed in trials that supplemented with DHA (−2.47 bpm; 95% CI: −3.47, −1.46 bpm), but not in trials with EPA.

Conclusions

The present meta-analysis provides strong clinical evidence demonstrating the effect of heart rate reduction by n−3 LCPUFA supplementation. When DHA or EPA administered alone, heart rate was slowed by DHA rather than by EPA.

Resting heart rate, heart rate reserve, and metabolic syndrome in professional firefighters: A cross-sectional study

BACKGROUND

Little is known about the associations of resting heart rate (RHR) and heart rate reserve (HRR) with metabolic syndrome (MetS) in firefighters.

METHODS

For each of 288 professional firefighters, HRR was calculated as the difference between measured RHR and estimated maximum HR. For comparison, VO₂ max based on a treadmill test was included. MetS was defined according to the NCEP/ATP III criteria.

RESULTS

The prevalence of MetS was 14.2%. The average of RHR was 61.5 beat/min. Only 5.8% of the firefighters had RHR of ≥80 beat/min. Between the firefighters in the lowest and highest quintiles, the prevalence ratios (95% confidence intervals) for MetS were 1.88 (0.71-4.94), 5.90 (1.74-20.02), and 8.03 (1.86-34.75) for RHR, HRR, and VO₂ max, respectively. Both HRR and VO₂ max, but not RHR, were significantly associated with MetS and its most component risk factors in middle-aged firefighters.

CONCLUSIONS

HRR, a simple cardiovascular fitness measure, was inversely associated with MetS among middle-aged professional firefighters.

Resting heart rate and impaired glucose regulation in middle-aged and elderly Chinese people: a cross-sectional analysis

Background

Elevated resting heart rate (RHR) has been reported to be associated with metabolic syndrome and type 2 diabetes. The aim of this study was to explore whether a positive relationship exists between RHR and impaired glucose regulation (IGR) among middle-aged and older Chinese individuals.

Methods

We conducted a cross-sectional analysis that included a total of 9898 subjects (3194 men and 6704 women) in a Chinese population. The RHRs were derived from ECG recordings, and the subjects were stratified based on RHR quartiles.

Results

RHR levels were significantly higher in the subjects with isolated impaired fasting glucose (i-IFG), isolated impaired glucose tolerance (i-IGT), IFG + IGT and diabetes than in those with normal glucose regulation. When multivariate logistic regression analyses were performed, the odds ratios were substantially higher for the subjects with IGR (odds ratio 2.19, 95% confidence interval 1.85–2.58) in the fourth RHR quartile compared with those in the first quartile after adjustment for potential confounding covariates, and the corresponding OR for the combined IGR and type 2 diabetes group was 2.56 (95% CI 2.20–2.98, p < 0.001). Multiple regression analyses demonstrated that RHR was significantly associated with fasting plasma glucose, 2-h OGTT plasma glucose and A1c.

Conclusions

Our cross-sectional findings provide evidence that high RHR is associated with existing IGR among middle-aged and older Chinese individuals.

Effects of Metabolically Healthy and Unhealthy Obesity on Prolongation of Corrected QT Interval

Although obesity and the metabolic syndrome (MS) often co-occur, many obese (OB) subjects have a favorable metabolic profile. It is unclear whether these factors independently influence cardiac electrophysiology including prolongation of the QT interval. We examined associations among obesity, MS, and prolonged corrected QT (QTc) interval in a large sample of Chinese research participants aged ≥35 years recruited from rural areas of Liaoning Province during 2012 to 2013. Of the 11,209 participants, 6,364 (56.8%) were nonobese and metabolically healthy (OB-/MS-), 2,853 (25.5%) were OB-/MS+, 493 (4.4%) were OB+/MS-, and 1,499 (13.4%) were OB+/MS+. Mean (±SD) QTc intervals were higher in OB-/MS+ (436.3 ± 24.3) and OB+/MS+ (436.6 ± 25.9) participants but not OB+/MS- participants (425.4 ± 24.0) than in OB-/MS- participants (426.8 ± 21.5, p <0.001), and the prevalence of QTc prolongation was higher in OB-/MS+ and OB+/MS+ participants (adjusted odds ratios [aOR] 1.68, 95% confidence interval [CI] 1.52 to 1.85; aOR 1.92, 95% CI 1.69 to 2.17, respectively) compared with OB-/MS- group but not in OB+/MS- participants (aOR 0.92, 95% CI 0.73 to 1.15). Prevalence increased with each MS component (aOR 1.27, 95% CI 1.22 to 1.32) but not with body mass index (aOR 1.01, 95% CI 0.99 to 1.02). In conclusion, prolonged QTc interval is associated with the MS and not independently associated with obesity.

Resting heart rate and risk of metabolic syndrome in adults: a dose-response meta-analysis of observational studies

The magnitude of the risk of metabolic syndrome (MetS) with increased resting heart rate (RHR) has been inconsistently reported in some observational studies, and whether a dose-response relationship exists between RHR and MetS is unclear. We performed a meta-analysis including dose-response analysis to quantitatively evaluate this association in adults. We searched PubMed, Web of Knowledge, China National Knowledge Infrastructure, and WanFang databases for articles published up to April 2, 2016. A random-effects model was used to pool relative risks (RRs) and 95% confidence intervals (CIs); restricted cubic spline function was used to assess the dose-response relationship. Seven prospective cohort studies and 10 cross-sectional studies with a total of 169,786 participants were included. The pooled RR was 2.10 (95% CI 1.80-2.46, I ² = 79.8%, n = 13) for the highest versus reference RHR category and 1.28 (95% CI 1.23-1.34, I ² = 87.7%, n = 15) for each 10 beats per minute (bpm) increment in RHR. We found no evidence of a nonlinear dose-response association between RHR and MetS (P _nonlinearity = 0.201). The relationship was consistent in most subgroup analyses and robust on sensitivity analysis. No significant publication bias was observed. This meta-analysis suggests that risk of MetS may be increased with elevated RHR.

Association of metabolic syndrome and electrocardiographic markers of subclinical cardiovascular disease

BACKGROUND

The metabolic syndrome (MetS) and its components are well-established risk factors for cardiovascular diseases (CVD). It is inconclusive whether MetS and MetS score are associated with electrocardiographic markers of subclinical CVD, therefore we investigated this in a population without pre-existing CVD.

METHODS

We performed a cross-sectional analysis in the Netherlands Epidemiology of Obesity study, a population-based cohort including 6671 participants aged 45-65. We excluded participants with pre-existing CVD (n = 499) or missing MetS components (n = 58). MetS was defined based on a modified definition of Adult Treatment Panel III. Subclinical CVD parameters were determined with 12-lead ECGs. MetS score was defined as number of abnormal MetS components and obesity as Body Mass Index (BMI) ≥30 kg/m². We performed weighted adjusted linear regression analyses.

RESULTS

Our study population (n = 6114) had a mean (SD) BMI of 26.3 (4.4) kg/m² and MetS was present in 24% of participants. All ECG parameters differed between participants with and without MetS. Per additional MetS component, heart rate was 0.17 SD (95% CI 0.15, 0.19) higher, P wave duration, QRS complex duration and corrected QT interval were longer [0.07 SD (0.05, 0.10), 0.04 SD (0.01, 0.06) and 0.05 SD (0.02, 0.08) respectively], P wave axis, T wave axis and QRS axis were lower [-0.10 SD (-0.12, -0.07), -0.07 SD (-0.10, -0.05) and -0.19 SD (-0.22, -0.16)] and percentage small Q-waves also increased per additional MetS component. Associations were stronger in non-obese than obese participants. In joint modelling of all MetS components, increased waist circumference showed strongest associations with ECG parameters.

CONCLUSIONS

Metabolic syndrome score and its individual components, in particular abdominal obesity, are associated with ECG markers of subclinical CVD, showing the importance of limiting the amount of MetS components in both obese and non-obese persons.

Clinical evaluation of vasomotor system functionality in type 2 diabetic Patients

BACKGROUND

Autonomic neuropathy and vital organ dysfunctions are the known complications in type 2 diabetes Mellitus (DM). Genetic endowments involving individuals make subtle differences in physiological systems, particularly at the time of sickness. Hence, the presented study was designed to evaluate the vasomotor system in healthy people and type 2 DM cases for determining any functionality differences between the mentioned groups.

METHODS

Sixty patients with type 2 diabetes (case group) and sixty healthy subjects (control group) matched for age and sex were enrolled in the study. Then, the performance of vasomotor system was assessed using valsalva maneuver, cold pressor, sustained hand-grip and mental arithmetic tests and the differences were determined via statistical methods.

RESULTS

According to our findings, abnormal response to valsalva maneuver was found in the case group (P=0.028) and the same response was seen about mental arithmetic evaluations. In the case of cold pressor and sustained hand-grip tests, remarkable differences were not found in both groups. Important differences were also found among vasomotor dysfunction and the time of DM labeling.

CONCLUSION

This study showed a higher incidence of vasomotor dysfunction in DM patients. However, revision in cold pressor and sustained hand-grip tests definition as well as methodology was recommended.

Markers of sympathetic nervous system activity associate with complex plasma lipids in metabolic syndrome subjects

BACKGROUND AND AIMS

Plasma sphingolipids including ceramides, and gangliosides are associated with insulin resistance (IR) through effects on insulin signalling and glucose metabolism. Our studies of subjects with metabolic syndrome (MetS) showed close relationships between IR and sympathetic nervous system (SNS) activity including arterial norepinephrine (NE). We have therefore investigated possible associations of IR and SNS activity with complex lipids that are involved in both insulin sensitivity and neurotransmission.

METHODS

We performed a cross-sectional assessment of 23 lipid classes/subclasses (total 339 lipid species) by tandem mass spectrometry in 94 overweight untreated subjects with IR (quantified by HOMA-IR, Matsuda index and plasma insulin).

RESULTS

Independently of IR parameters, several circulating complex lipids associated significantly with arterial NE and NEFA (non-esterified fatty acids) and marginally with heart rate (HR). After accounting for BMI, HOMA-IR, systolic BP, age, gender, and correction for multiple comparisons, these associations were significant (p < 0.05): NE with ceramide, phosphatidylcholine, alkyl- and alkenylphosphatidylcholine and free cholesterol; NEFA with mono- di- and trihexosylceramide, G_M3 ganglioside, sphingomyelin, phosphatidylcholine, alkyl- and alkenylphosphatidylcholine, phosphatidylinositol and free cholesterol; HR marginally (p = or <0.1>0.05) with ceramide, G_M3 ganglioside, sphingomyelin, lysophosphatidylcholine, phosphatidylinositol, lysophosphatidylinositol and free cholesterol. Multiple subspecies of these lipids significantly associated with NE and NEFA. None of the IR biomarkers associated significantly with lipid classes/subclasses after correction for multiple comparisons.

CONCLUSIONS

This is the first demonstration that arterial norepinephrine and NEFA, that reflect both SNS activity and IR, associate significantly with circulating complex lipids independently of IR, suggesting a role for such lipids in neural mechanisms operating in MetS.

Identification of genomic loci associated with resting heart rate and shared genetic predictors with all-cause mortality

Resting heart rate is a heritable trait correlated with life span. Little is known about the genetic contribution to resting heart rate and its relationship with mortality. We performed a genome-wide association discovery and replication analysis starting with 19.9 million genetic variants and studying up to 265,046 individuals to identify 64 loci associated with resting heart rate (P < 5 × 10-8); 46 of these were novel. We then used the genetic variants identified to study the association between resting heart rate and all-cause mortality. We observed that a genetically predicted resting heart rate increase of 5 beats per minute was associated with a 20% increase in mortality risk (hazard ratio 1.20, 95% confidence interval 1.11-1.28, P = 8.20 × 10-7) translating to a reduction in life expectancy of 2.9 years for males and 2.6 years for females. Our findings provide evidence for shared genetic predictors of resting heart rate and all-cause mortality.

Changes in sleep duration and risk of metabolic syndrome: the Kailuan prospective study

Using a large longitudinal data set spanning 4 years, we examined whether a change in self-reported sleep duration is associated with metabolic syndrome (MetS). Current analysis included 15,753 participants who were free of MetS during both 2006–2007 and 2010–2011. Sleep duration was categorized into seven groups: ≤5.5 h, 6.0–6.5 h, 7.0 h, 7.5–8.0 h, ≥8.5 h, decrease ≥2 h, and increase ≥2 h. Cox proportional hazards models were used to calculate hazard ratios (HRs) and their confidence intervals (CI) for MetS, according to sleep duration. Compared to the reference group of persistent 7-h sleepers, a decrease of ≥2 h sleep per night was associated with a higher risk of incident MetS (HR = 1.23, 95% CI = 1.05–1.44) in analyses adjusted for age, sex, sleep duration at baseline, marital status, monthly income per family member, education level, smoking status, drinking status, physical activity, body mass index, snoring status and resting heart rate. An increased risk of MetS incidence was also observed in persistent short sleepers (average ≤5.5 h/night; HR = 1.22, 95% CI = 1.01–1.50). This study suggests individuals whose sleep duration decreases ≥2 h per night are at an increased risk of MetS.

Alterations in heart rate variability during everyday life are linked to insulin resistance. A role of dominating sympathetic over parasympathetic nerve activity?

Aims

To evaluate the role of the autonomic nervous system (ANS) in the development of insulin resistance (IR) and assess the relationship between IR and activity of ANS using power spectrum analysis of heart rate variability (HRV).

Subjects and methods

Twenty-three healthy first-degree relatives of patients with type 2 diabetes (R) and 24 control subjects without family history of diabetes (C) group-matched for age, BMI and sex were included. Insulin sensitivity (M value) was assessed by hyperinsulinemic (56 mU/m²/min) euglycemic clamp. Activity of the ANS was assessed using power spectrum analysis of HRV in long-term recordings, i.e., 24-h ECG monitoring, and in short-term recordings during manoeuvres activating the ANS. Computed tomography was performed to estimate the amount and distribution of abdominal adipose tissue.

Results

Insulin sensitivity (M value, mg/kg lbm/min) did not differ significantly between the R and C groups. Total spectral power (P_tot) and very low-frequency (P_VLF) power was lower in R than C during 24 h ECG-recordings (p = 0.02 and p = 0.03). The best fit multiple variable linear regression model (r² = 0.37, p < 0.001 for model) indicated that body composition (BMI) and long-term low to high frequency (LF/HF) power ratio (std β = −0.46, p = 0.001 and std β = −0.28, p = 0.003, respectively) were significantly and independently associated with the M value.

Conclusion

Altered heart rate variability, assessed by power spectrum analysis, during everyday life is linked to insulin resistance. The data suggest that an increased ratio of sympathetic to parasympathetic nerve activity, occurring via both inherited and acquired mechanisms, could potentially contribute to the development of type 2 diabetes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0411-8) contains supplementary material, which is available to authorized users.