Discover the most talked about and latest scientific content & concepts.

Journal: Journal of the American Heart Association


Physical activity (PA) has an established favorable impact on cardiovascular disease (CVD) outcomes and quality of life. In this study, we aimed to estimate the economic effect of moderate-vigorous PA on medical expenditures and utilization from a nationally representative cohort with and without CVD.

Concepts: Medicine, Disease, Life, Cardiovascular disease, Economics, Non-infectious disease, Cost


The 2008 Physical Activity Guidelines for Americans recommends that adults accumulate moderate-to-vigorous physical activity (MVPA) in bouts of ≥10 minutes for substantial health benefits. To what extent the same amount of MVPA accumulated in bouts versus sporadically reduces mortality risk remains unclear.

Concepts: Health insurance


A “Christmas holiday effect” showing elevated cardiovascular mortality over the Christmas holidays (December 25 to January 7) was demonstrated previously in study from the United States. To separate the effect of seasonality from any holiday effect, a matching analysis was conducted for New Zealand, where the Christmas holiday period falls within the summer season.

Concepts: United States, Pacific Ocean, Australia, Autumn, New York City, Antarctica, Christmas, Northern Hemisphere


Background Systemic iron status has been implicated in atherosclerosis and thrombosis. The aim of this study was to investigate the effect of genetically determined iron status on carotid intima-media thickness, carotid plaque, and venous thromboembolism using Mendelian randomization. Methods and Results Genetic instrumental variables for iron status were selected from a genome-wide meta-analysis of 48 972 subjects. Genetic association estimates for carotid intima-media thickness and carotid plaque were obtained using data from 71 128 and 48 434 participants, respectively, and estimates for venous thromboembolism were obtained using data from a study incorporating 7507 cases and 52 632 controls. Conventional 2-sample summary data Mendelian randomization was performed for the main analysis. Higher genetically determined iron status was associated with increased risk of venous thromboembolism. Odds ratios per SD increase in biomarker levels were 1.37 (95% CI 1.14-1.66) for serum iron, 1.25 (1.09-1.43) for transferrin saturation, 1.92 (1.28-2.88) for ferritin, and 0.76 (0.63-0.92) for serum transferrin (with higher transferrin levels representing lower iron status). In contrast, higher iron status was associated with lower risk of carotid plaque. Corresponding odds ratios were 0.85 (0.73-0.99) for serum iron and 0.89 (0.80-1.00) for transferrin saturation, with concordant trends for serum transferrin and ferritin that did not reach statistical significance. There was no Mendelian randomization evidence of an effect of iron status on carotid intima-media thickness. Conclusions These findings support previous work to suggest that higher genetically determined iron status is protective against some forms of atherosclerotic disease but increases the risk of thrombosis related to stasis of blood.


Despite public awareness that tobacco secondhand smoke (SHS) is harmful, many people still assume that marijuana SHS is benign. Debates about whether smoke-free laws should include marijuana are becoming increasingly widespread as marijuana is legalized and the cannabis industry grows. Lack of evidence for marijuana SHS causing acute cardiovascular harm is frequently mistaken for evidence that it is harmless, despite chemical and physical similarity between marijuana and tobacco smoke. We investigated whether brief exposure to marijuana SHS causes acute vascular endothelial dysfunction.

Concepts: Smoking, Tobacco, Tobacco smoking, Law, Endothelium, Endothelial dysfunction, Cannabis, Smoke


Health insurance has many benefits including improved financial security, greater access to preventive care, and better self-perceived health. However, the influence of health insurance on major health outcomes is unclear. Sudden cardiac arrest prevention represents one of the major potential benefits from health insurance, given the large impact of sudden cardiac arrest on premature death and its potential sensitivity to preventive care.

Concepts: Health care, Public health, Myocardial infarction, Cardiac arrest, Cardiopulmonary resuscitation, Economics, Sudden cardiac death, Clinical death


Caffeine in doses <400 mg is typically not considered arrhythmogenic, but little is known about the additional ingredients in energy drinks. We evaluated the ECG and blood pressure (BP) effects of high-volume energy drink consumption compared with caffeine alone.

Concepts: Randomized controlled trial, Caffeine, Energy drink


There are substantial differences in the distribution of adipose tissue between women and men. We assessed the sex-specific relationships and their differences between measures of general and central adiposity and the risk of incident myocardial infarction (MI).

Concepts: Myocardial infarction, Obesity, Muscle, Gender, Adipose tissue



Background Energy drinks have been linked to an increase in emergency room visits and deaths. We aim to determine the impact of energy drinks on electrocardiographic and hemodynamic parameters in young healthy volunteers. Methods and Results A randomized, double-masked, placebo-controlled, crossover study was conducted in healthy volunteers. Participants consumed 32 oz of either energy drink A, energy drink B, or placebo within 60 minutes on 3 study days with a 6-day washout period in between. The primary end point of QT c interval and secondary end points of QT interval, PR interval, QRS duration, heart rate, and brachial and central blood pressures were measured at baseline, and every 30 minutes for 240 minutes. A repeated-measures 2-way analysis of variance was performed with the main effects of intervention, time, and an interaction of intervention and time. Thirty-four participants were included (age 22.1±3.0 years). The interaction term of intervention and time was statistically significant for Bazett’s corrected QT interval, Fridericia’s corrected QT interval, QT , PR , QRS duration, heart rate, systolic blood pressure, diastolic blood pressure, central systolic blood pressure, and central diastolic blood pressure (all P<0.001). The maximum change from baseline in Bazett's corrected QT interval for drinks A, B, and placebo were +17.9±13.9, +19.6±15.8, and +11.9±11.1 ms, respectively ( P=0.005 for ANOVA ) ( P=0.04 and <0.01, respectively compared with placebo). Peripheral and central systolic and diastolic blood pressure were statistically significantly different compared with placebo (all P<0.001). Conclusion Energy drinks significantly prolong the QT c interval and raise blood pressure. Clinical Trial Registration URL : . Unique identifier: NCT03196908.