scholarly journals Caffeine and Cognitive Functions in Sports: A Systematic Review and Meta-Analysis

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 868
Author(s):  
Jorge Lorenzo Calvo ◽  
Xueyin Fei ◽  
Raúl Domínguez ◽  
Helios Pareja-Galeano

Cognitive functions are essential in any form of exercise. Recently, interest has mounted in addressing the relationship between caffeine intake and cognitive performance during sports practice. This review examines this relationship through a structured search of the databases Medline/PubMed and Web of Science for relevant articles published in English from August 1999 to March 2020. The study followed PRISMA guidelines. Inclusion criteria were defined according to the PICOS model. The identified records reported on randomized cross-over studies in which caffeine intake (as drinks, capsules, energy bars, or gum) was compared to an identical placebo situation. There were no filters on participants’ training level, gender, or age. For the systematic review, 13 studies examining the impacts of caffeine on objective measures of cognitive performance or self-reported cognitive performance were selected. Five of these studies were also subjected to meta-analysis. After pooling data in the meta-analysis, the significant impacts of caffeine only emerged on attention, accuracy, and speed. The results of the 13 studies, nevertheless, suggest that the intake of a low/moderate dose of caffeine before and/or during exercise can improve self-reported energy, mood, and cognitive functions, such as attention; it may also improve simple reaction time, choice reaction time, memory, or fatigue, however, this may depend on the research protocols.

Nutrients ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 2571
Author(s):  
Tianxiang Cui ◽  
Jiaxuan Xi ◽  
Chanyuan Tang ◽  
Jianwen Song ◽  
Jinbo He ◽  
...  

Food intake has been shown to be related to several environmental factors including the presence of music. However, previous findings of the relationship between music and food intake are inconsistent. In the present study, a systematic review and meta-analysis was conducted to quantitatively review the extent to which music is associated with food intake as well as to investigate potential moderators that might have contributed to the heterogeneity of the existing findings. Literature was searched on four databases (i.e., PsycINFO, Web of Science, PubMed, and ProQuest Dissertations and Theses) and Google Scholar. Nine articles published from 1989 to 2020 met our inclusion criteria. A meta-analysis was carried out via a three-level random-effects model. The overall effect size (i.e., Hedges’ g) was 0.19 (95% Confidence Interval: −0.003, 0.386; SE = 0.10, t = 1.99, p = 0.054), indicating a marginally significant but small effect size. Body Mass Index (F(1, 21) = 5.11, p = 0.035) was found to significantly contribute to the heterogeneity of effect sizes, with larger positive effects of music on food intake for individuals with higher BMI. However, music-related features did not significantly moderate the relationship between music and food intake. More experimental studies are needed to update the current meta-analysis and get a better understanding of this topic.


Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 506
Author(s):  
Bernardo Romão ◽  
Ana Luísa Falcomer ◽  
Gabriela Palos ◽  
Sandra Cavalcante ◽  
Raquel Braz Assunção Botelho ◽  
...  

This study aimed to perform a systematic review and meta-analysis of the glycemic index (GI) of gluten-free bread (GFB) and its main ingredients. The systematic review followed PRISMA guidelines, using seven electronic databases (PubMed, EMBASE, Scopus, Science Direct, Web of Science, gray literature research with Google Scholar, and patents with Google Patent tool), from inception to November 2020. Eighteen studies met the inclusion criteria evaluating 132 GFB samples. Five articles tested GI in vivo, eleven in vitro; and two studies tested both methods. The analysis showed that 60.7% (95% CI: 40.2–78.1%) of the samples presented high glycemic indexes, evidencing a high glycemic profile for GFB. Only 18.2% (95% CI: 11.7–27.2%) of the bread samples presented in the studies were classified as a low GI. Meta-analysis presented moderate/low heterogenicity between studies (I2 = 61% and <1% for both high and low GIs) and reinforced the proportion of high GIs. Lower GIs were found in formulations based on Colocasia esculenta flour or enriched with fiber, yogurt and curd cheese, sourdough, psyllium, hydrocolloids, enzymes, fructans, and resistant starch, highlighting the efficacy of these ingredients to lower GFBs’ GI. GFB tends to present high GI, impacting the development of chronic diseases when consumed.


Author(s):  
Cristina Elena Petre

There are three hypotheses regarding the relationship between Self-Concept Clarity (SCC) and Internet use. It was argued that Internet use: 1) decreases SCC, 2) increases SCC, 3) does not relate with SCC. The present study, in the form of a systematic and meta-analytic synthesis, aimed to explore: a) the extent empirical evidence can support each hypothesis; b) how Internet use-SCC relationship was addressed across studies; c) the intensity of the Internet use –SCC relationship; d) potential moderators. Twenty-one studies (N = 8,910) met the inclusion criteria for the systematic review (i.e., being quantitative, written in English, concerned with Internet use -SCC relationship) and 11 studies (N = 3,298) met the additional criteria for meta-analysis (i.e., being correlational, using self-evaluation instruments, quantifying general Internet use and including the information needed to calculate the meta-analysis specific indicators). Results emphasized that all three hypotheses are plausible, as distinct dimensions of Internet use related differently with SCC. However, the conclusions were limited by the extensive use of cross-sectional design. For general Internet use and SCC relationship the overall effect was -0.350, p < .01. Some moderators were significant: cultural background, Internet operationalization, age homogeneity, participants rewarding. This paper outlines the complexity of SCC – Internet relationship and underlines some of the gaps that should be further addressed. Implications and limits of the study (e.g., publication bias, excluded outcomes in the meta-analysis or possible omission of moderators) are discussed.


Nutrients ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1186 ◽  
Author(s):  
Madeline Cooke ◽  
Alison Coates ◽  
Elizabeth Buckley ◽  
Jonathan Buckley

Lutein is a carotenoid that reduces the risk of some chronic diseases, possibly by altering physical activity behavior. The objective of this study was to conduct a systematic review of studies examining the relationship between lutein status (dietary intake/blood concentration) and physical activity. Peer-reviewed studies published in Medline, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Scopus, and Embase were included if they reported a measure of association between lutein status and physical activity. Seventeen studies met the inclusion criteria. Eleven reported positive associations, three reported mixed results, and three reported no association. Two studies used objective measures of lutein status (blood concentration) and physical activity (accelerometry) and reported positive associations, with correlations of ≥0.36 and differences of ≥57% in physical activity between upper and lower tertiles. Studies using self-report measures reported weaker correlations (r = 0.06 to 0.25), but still more physical activity (18% to ≥600% higher) in those with the highest compared with the lowest lutein status. Higher lutein status may be associated with higher levels of physical activity, which may contribute to a reduced risk of chronic disease.


2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Masoud Mohammadi ◽  
Mohsen Kazeminia ◽  
Nasrin Abdoli ◽  
Behnam Khaledipaveh ◽  
Shamarina Shohaimi ◽  
...  

Abstract Background Opioids addiction and misuse are among the major problems in the world today. There have been several preliminary studies examining the effect of methadone on depression among addicts, however, these studies have reported inconsistent and even contradictory results. Therefore, the aim of the present study was to determine the effect of methadone on depression in addicts in Iran and around the world, using a meta-analysis approach. Methods This study was a systematic review and meta-analysis including articles published in the SID, MagIran, IranMedex, IranDoc, Cochrane, Embase, ScienceDirect, Scopus, PubMed and Web of Science databases were searched systematically to find articles published from 2006 to March 2019. Heterogeneity index was determined using the Cochran's test (Qc) and I2. Considering heterogeneity of studies, the random effects model was used to estimate the standardized difference of mean score for depression. Subsequently, the level of depression reduction in Iran and worldwide in the intervention group before and after the testwas measured. Results A total of 19 articles met the inclusion criteria, and were therefore selected for this systematic review and meta-analysis. The sample size of the intervention group in the selected studies was 1948. According to the meta-analysis results, the mean depression score in the intervention group was 26.4 ± 5.6 and 18.4 ± 2.6 before and after intervention respectively, indicating the reducing effect of methadone on depression, and this difference was statistically significant (P < 0.01). Conclusion The results of the present study show that methadone significantly reduces depression in addicts. Therefore, regular methadone use can be part of a drug treatment plan.


Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 957 ◽  
Author(s):  
Dannielle Glencorse ◽  
Kate Plush ◽  
Susan Hazel ◽  
Darryl D’Souza ◽  
Michelle Hebart

There are conflicting reports regarding the effect of farrowing house accommodation on piglet performance. The aim of this investigation was to use a systematic review and meta-analyses to summarise the results of publications that focused on direct comparisons between full confinement conventional crates and various designs of loose-housed farrowing pens from loading until weaning. Literature searches in Scopus, BIOSIS Previews, Cab Abstracts, and Web of Science identified 6695 articles. Twenty-two publications were retained for the systematic review and individual meta-analyses after screening for inclusion criteria. The random effects meta-analyses were performed on crate versus pen for number of piglets born alive, number of stillborn piglets, pre-weaning mortality, and number of piglets weaned. Additionally, the modifiers of confinement length (no confinement from loading until weaning or partial confinement for shorter periods of time in the early stages post parturition), enrichment (no enrichment or enrichment provided), and pen size (small, medium, or large) were examined. There was a 14% increase in the relative risk of piglet mortality in farrowing pens when they were compared with crates (p = 0.0015). The number of stillborns per litter was not different between the pen and crate. However, when providing enrichment in the pens, there was an increase in stillborns within farrowing crates versus pens (p = 0.009). There was no overall effect on piglets that were born alive or number weaned. As there is no difference between piglets born alive and mortality is significantly higher in farrowing pens, a reduction in the number of piglets weaned was expected but not observed, which was possibly due to the lack of weaning details provided in the publications. This was the first systematic review and meta-analysis conducted on the performance of farrowing accommodation and identified that farrowing pens do compromise post-natal piglet survival. Future efforts should focus on improving sow comfort in the farrowing crate to maximize both piglet and sow welfare.


2021 ◽  
Vol 9 ◽  
Author(s):  
Danying Yan ◽  
Xiaobao Zhang ◽  
Can Chen ◽  
Daixi Jiang ◽  
Xiaoxiao Liu ◽  
...  

Background: The viral shedding time (VST) of SARS-CoV-2 mainly determines its transmission and duration of infectiousness. However, it was heterogeneous in the existing studies. Here, we performed a meta-analysis to comprehensively summarize the VST of SARS-CoV-2.Methods: We searched PubMed, Web of Science, MedRxiv, BioRxiv, CNKI, CSTJ, and Wanfang up to October 25, 2020, for studies that reported VSTs of SARS-CoV-2. Pooled estimates and 95% CIs for the VSTs were calculated using log-transformed data. The VSTs in SARS-CoV-2 infections based on different demographic and clinical characteristics, treatments and specimens were stratified by subgroup analysis.Results: A total of 35 studies involving 3,385 participants met the inclusion criteria. The pooled mean VST was 16.8 days (95% CI: 14.8–19.4, I2 = 99.56%) in SARS-CoV-2 infections. The VST was significantly longer in symptomatic infections (19.7 days, 95% CI: 17.2–22.7, I2 = 99.34%) than in asymptomatic infections (10.9 days, 95% CI: 8.3–14.3, I2 = 98.89%) (P &lt; 0.05). The VST was 23.2 days (95% CI: 19.0–28.4, I2 = 99.24%) in adults, which was significantly longer than that in children (9.9 days, 95% CI: 8.1–12.2, I2 = 85.74%) (P &lt; 0.05). The VST was significantly longer in persons with chronic diseases (24.2 days, 95% CI: 19.2–30.2, I2 = 84.07%) than in those without chronic diseases (11.5 days, 95% CI: 5.3–25.0, I2 = 82.11%) (P &lt; 0.05). Persons receiving corticosteroid treatment (28.3 days, 95% CI: 25.6–31.2, I2 = 0.00%) had a longer VST than those without corticosteroid treatment (16.2 days, 95% CI: 11.5–22.5, I2 = 92.27%) (P = 0.06). The VST was significantly longer in stool specimens (30.3 days, 95% CI: 23.1–39.2, I2 = 92.09%) than in respiratory tract specimens (17.5 days, 95% CI: 14.9–20.6, I2 = 99.67%) (P &lt; 0.05).Conclusions: A longer VST was found in symptomatic infections, infected adults, persons with chronic diseases, and stool specimens.


2020 ◽  
Author(s):  
Kainan Lin ◽  
Xiaoting Sun ◽  
Xiao Wang ◽  
Hanchu Wang ◽  
Xia Chen

AbstractConcentrations of circulating adipokines in non-obese polycystic ovary syndrome (PCOS) patients had been reported in many researches, however, these results were conflicting. The aim of this meta-analysis was to assess whether the levels of circulating adipokines were changed in non-obese PCOS. To identify eligible studies, literature research was performed in the database of PubMed, Embase, Web of Science without the restriction of region, publication or language. Of the total studies found, only 81 met the inclusion criteria. The meta-analysis showed that circulating levels of adiponectin [-0.95 (95% CI, −1.36 to −0.53)] decreased statistically in non-obese PCOS women. On the contrary, circulating levels of chemerin [1.13 (95% CI, 0.08 to 2.18)], leptin [0.47 (95% CI, 0.13 to 0.81)], resistin [0.45 (95% CI, 0.03 to 0.88)] and visfatin [1.38 (95% CI, 0.68 to 2.09)] increased significantly in non-obese PCOS females. Besides, there was no statistically significant change in the circulating levels of apelin [0.32 (95% CI, −1.34 to 1.99), irisin [1.01(95% CI, −0.68 to 2.70), omentin [-0.37(95% CI, −1.05 to 0.31)] and vaspin [0.09(95% CI, −0.14 to 0.32)] in non-obese PCOS patients. Scientific evidence suggested that the levels of circulating adipokines altered in non-obese PCOS patients compared with controls. Independent of the degree of obesity, the abnormal change of circulating adipokines levels might play an important role in the occurrence and development of PCOS.


Author(s):  
Arshid Yousefi Avarvand ◽  
Mehrdad Halaji ◽  
Donya Zare ◽  
Meysam Hasannejad-Bibalan ◽  
Hadi Sedigh Ebrahim-Saraie

Background: Streptococcus pneumoniae is an important pathogen of children, mostly in developing countries. We aimed to investigate the prevalence of invasive S. pneumoniae among Iranian children using a systematic review and meta-analysis. Methods: A systematic search was carried out to identify papers published by Iranian authors in the Web of Science, PubMed, Scopus, and Google Scholar electronic databases from January of 2010 to December of 2017. Then, seven publications that met our inclusion criteria were selected for data extraction and analysis. Results: Totally, one study was multicenter, and six were single-center based studies. Meanwhile, all of the included studied performed among hospitalized patients. Seven studies reported the prevalence of invasive S. pneumoniae isolated from children, of these the pooled prevalence of S. pneumoniae was 2.5% (95% CI: 0.7%-9.1%). Conclusion: The overall prevalence of invasive S. pneumoniae infections among Iranian children is low (2.5%). However, further clinical studies are required to elucidate the burden of infections among Iranian children, especially in eastern regions.


2020 ◽  
Vol 10 (2) ◽  
pp. 98-115 ◽  
Author(s):  
Majid Mobasseri ◽  
Masoud Shirmohammadi ◽  
Tarlan Amiri ◽  
Nafiseh Vahed ◽  
Hossein Hosseini Fard ◽  
...  

Background: Diabetes is referred to a group of diseases characterized by high glucose levels in blood. It is caused by a deficiency in the production or function of insulin or both, which can occur because of different reasons, resulting in protein and lipid metabolic disorders. The aim of this study was to systematically review the prevalence and incidence of type 1 diabetes in the world. Methods: A systematic search of resources was conducted to investigate the prevalence and incidence of type 1 diabetes in the world. The databases of Medline (via PubMed and Ovid),ProQuest, Scopus, and Web of Science from January 1980 to September 2019 were searched to locate English articles. The located articles were screened in multiple levels of title, abstract,and full-text and final studies that met the inclusion criteria were retrieved and included in the study. Results: From 1202 located articles, 193 studies were included in this systematic review. The results of meta-analysis showed that the incidence of type 1 diabetes was 15 per 100,000 people and the prevalence was 9.5% (95% CI: 0.07 to 0.12) in the world, which was statistically significant. Conclusion: According to the results, the incidence and prevalence of type 1 diabetes are increasing in the world. As a result, insulin will be difficult to access and afford, especially in underdeveloped and developing countries.


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