Evidence of premature vascular dysfunction in young adults who regularly use e-cigarettes and the impact of usage length.

BACKGROUND: Electronic (e-) cigarettes are increasingly popular tobacco products on the US market. Traditional tobacco products are known to cause vascular dysfunction, one of the earliest indicators of cardiovascular disease (CVD) development. However, little is known about the effect of regular e-cigarette use on vascular function. The purpose of this study was to investigate the impact of regular e-cigarette use on vascular function and cardiovascular health in young, healthy adults. METHODS: Twenty-one regular users of e-cigarettes (ECU) and twenty-one demographically matched non-users (NU) completed this study. Vascular health was assessed in the cutaneous microcirculation through different reactivity tests to evaluate overall functionality, endothelium-dependent vasodilation (EDD), and endothelium-independent vasodilation (EID). Macrovascular function was assessed using flow-mediated dilation (FMD). RESULTS: Our results suggest that regular users of e-cigarettes present with premature microvascular impairment when compared to non-users. Specifically, they exhibit lower hyperemic (p = 0.003), thermal (p = 0.010), and EDD (p = 0.004) responses. No differences in EID between the groups were identified. We also identified that individuals who use e-cigarettes for longer than 3 years also present with systemic manifestations, as observed by significantly reduced macrovascular (p = 0.002) and microvascular (p ≤ 0.044) function. CONCLUSIONS: Our novel data suggests that young, apparently healthy, regular users of e-cigarettes present with premature vascular dysfunction in the microcirculation when compared to non-users. We have also identified systemic vascular dysfunction affecting both the micro and macrovasculature in those young individuals who used e-cigarettes for longer than 3 years. Taken together, these findings associate regular e-cigarette use with premature vascular dysfunctions and adverse cardiovascular outcomes.

Acetic Acid Supplementation: Effect on Resting and Exercise Energy Expenditure and Substrate Utilization.

The purpose of this study was to investigate the influence of acetic acid (apple cider vinegar; ACV) supplementation on resting and exercise energy expenditure and substrate utilization. Using a randomized, double blind, crossover design, 16 healthy subjects were supplemented for 4 d with either ACV (30-ml/d) mixed in 1 L of a non-nutritive lemon-flavored drink or a placebo (PLA). They were then assessed via indirect calorimetry for resting energy expenditure (REE) and substrate utilization. This was immediately followed by the assessment of steady state cycling exercise energy expenditure at 40 W (EEE-40) and 80 W (EEE-80) and substrate utilization. Results: Neither REE nor resting substrate utilization were significantly different between groups (p ≥ .05). During cycling exercise at both 40W and 80W, there were no significant differences observed between groups for energy expenditure (EEE-40: ACV 4.13 ± 0.79, PLA 4.37 ± 0.61 kcal/min; EEE-80: ACV 6.09 ± 0.87, PLA 6.26 ± 0.72 kcal/min) or substrate utilization (40W carbohydrate: ACV 0.72 ± 0.19, PLA 0.76 ± 0.16; fat: ACV 0.15 ± 0.07, PLA 0.16 ± 0.06 g/min), (80W carbohydrate: ACV 1.28 ± 0.32, PLA 1.34 ± 0.35; fat: ACV 0.14 ± 0.10, PLA 0.14 ± 0.10 g/min) (p ≥ .05). Conclusions: Recent findings suggest that chronic acetic acid supplementation is associated with significant reductions in body weight and body fat; however, the findings of the present study suggest that a semi-acute (4 d) acetic acid supplementation does not impact resting or exercise energy expenditure or substrate utilization.