University of Niš

About: University of Niš is a education organization based out in Niš, Serbia. It is known for research contribution in the topics: Population & Fading. The organization has 3603 authors who have published 9418 publications receiving 100759 citations. The organization is also known as: Univerzitet u Nišu.

Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: Systematic review and meta-analysis

Abstract: ContextAntioxidant supplements are used for prevention of several diseases.ObjectiveTo assess the effect of antioxidant supplements on mortality in randomized primary and secondary prevention trials.Data Sources and Trial SelectionWe searched electronic databases and bibliographies published by October 2005. All randomized trials involving adults comparing beta carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium either singly or combined vs placebo or vs no intervention were included in our analysis. Randomization, blinding, and follow-up were considered markers of bias in the included trials. The effect of antioxidant supplements on all-cause mortality was analyzed with random-effects meta-analyses and reported as relative risk (RR) with 95% confidence intervals (CIs). Meta-regression was used to assess the effect of covariates across the trials.Data ExtractionWe included 68 randomized trials with 232 606 participants (385 publications).Data SynthesisWhen all low- and high-bias risk trials of antioxidant supplements were pooled together there was no significant effect on mortality (RR, 1.02; 95% CI, 0.98-1.06). Multivariate meta-regression analyses showed that low-bias risk trials (RR, 1.16; 95% CI, 1.05-1.29) and selenium (RR, 0.998; 95% CI, 0.997-0.9995) were significantly associated with mortality. In 47 low-bias trials with 180 938 participants, the antioxidant supplements significantly increased mortality (RR, 1.05; 95% CI, 1.02-1.08). In low-bias risk trials, after exclusion of selenium trials, beta carotene (RR, 1.07; 95% CI, 1.02-1.11), vitamin A (RR, 1.16; 95% CI, 1.10-1.24), and vitamin E (RR, 1.04; 95% CI, 1.01-1.07), singly or combined, significantly increased mortality. Vitamin C and selenium had no significant effect on mortality.ConclusionsTreatment with beta carotene, vitamin A, and vitamin E may increase mortality. The potential roles of vitamin C and selenium on mortality need further study.

Effectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max Improvements: A Systematic Review and Meta-Analysis of Controlled Trials

Abstract: Enhancing cardiovascular fitness can lead to substantial health benefits. High-intensity interval training (HIT) is an efficient way to develop cardiovascular fitness, yet comparisons between this type of training and traditional endurance training are equivocal. Our objective was to meta-analyse the effects of endurance training and HIT on the maximal oxygen consumption (VO2max) of healthy, young to middle-aged adults. Six electronic databases were searched (MEDLINE, PubMed, SPORTDiscus, Web of Science, CINAHL and Google Scholar) for original research articles. A search was conducted and search terms included ‘high intensity’, ‘HIT’, ‘sprint interval training’, ‘endurance training’, ‘peak oxygen uptake’, and ‘VO2max’. Inclusion criteria were controlled trials, healthy adults aged 18–45 years, training duration ≥2 weeks, VO2max assessed pre- and post-training. Twenty-eight studies met the inclusion criteria and were included in the meta-analysis. This resulted in 723 participants with a mean ± standard deviation (SD) age and initial fitness of 25.1 ± 5 years and 40.8 ± 7.9 mL·kg−1·min−1, respectively. We made probabilistic magnitude-based inferences for meta-analysed effects based on standardised thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject SDs for baseline VO2max. The meta-analysed effect of endurance training on VO2max was a possibly large beneficial effect (4.9 mL·kg−1·min−1; 95 % confidence limits ±1.4 mL·kg−1·min−1), when compared with no-exercise controls. A possibly moderate additional increase was observed for typically younger subjects (2.4 mL·kg−1·min−1; ±2.1 mL·kg−1·min−1) and interventions of longer duration (2.2 mL·kg−1·min−1; ±3.0 mL·kg−1·min−1), and a small additional improvement for subjects with lower baseline fitness (1.4 mL·kg−1·min−1; ±2.0 mL·kg−1·min−1). When compared with no-exercise controls, there was likely a large beneficial effect of HIT (5.5 mL·kg−1·min−1; ±1.2 mL·kg−1·min−1), with a likely moderate greater additional increase for subjects with lower baseline fitness (3.2 mL·kg−1·min−1; ±1.9 mL·kg−1·min−1) and interventions of longer duration (3.0 mL·kg−1·min−1; ±1.9 mL·kg−1·min−1), and a small lesser effect for typically longer HIT repetitions (−1.8 mL·kg−1·min−1; ±2.7 mL·kg−1·min−1). The modifying effects of age (0.8 mL·kg−1·min−1; ±2.1 mL·kg−1·min−1) and work/rest ratio (0.5 mL·kg−1·min−1; ±1.6 mL·kg−1·min−1) were unclear. When compared with endurance training, there was a possibly small beneficial effect for HIT (1.2 mL·kg−1·min−1; ±0.9 mL·kg−1·min−1) with small additional improvements for typically longer HIT repetitions (2.2 mL·kg−1·min−1; ±2.1 mL·kg−1·min−1), older subjects (1.8 mL·kg−1·min−1; ±1.7 mL·kg−1·min−1), interventions of longer duration (1.7 mL·kg−1·min−1; ±1.7 mL·kg−1·min−1), greater work/rest ratio (1.6 mL·kg−1·min−1; ±1.5 mL·kg−1·min−1) and lower baseline fitness (0.8 mL·kg−1·min−1; ±1.3 mL·kg−1·min−1). Endurance training and HIT both elicit large improvements in the VO2max of healthy, young to middle-aged adults, with the gains in VO2max being greater following HIT when compared with endurance training.