scholarly journals The Relationship between Whole Grain Intake and Body Weight: Results of Meta-Analyses of Observational Studies and Randomized Controlled Trials

Nutrients ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1245 ◽  
Author(s):  
Kevin C. Maki ◽  
Orsolya M. Palacios ◽  
Katie Koecher ◽  
Caleigh M. Sawicki ◽  
Kara A. Livingston ◽  
...  

Results from some observational studies suggest that higher whole grain (WG) intake is associated with lower risk of weight gain. Ovid Medline was used to conduct a literature search for observational studies and randomized controlled trials (RCTs) assessing WG food intake and weight status in adults. A meta-regression analysis of cross-sectional data from 12 observational studies (136,834 subjects) and a meta-analysis of nine RCTs (973 subjects) was conducted; six prospective cohort publications were qualitatively reviewed. Cross-sectional data meta-regression results indicate a significant, inverse correlation between WG intake and body mass index (BMI): weighted slope, −0.0141 kg/m2 per g/day of WG intake (95% confidence interval (CI): −0.0207, −0.0077; r = −0.526, p = 0.0001). Prospective cohort results generally showed inverse associations between WG intake and weight change with typical follow-up periods of five to 20 years. RCT meta-analysis results show a nonsignificant pooled standardized effect size of −0.049 kg (95% CI −0.297, 0.199, p = 0.698) for mean difference in weight change (WG versus control interventions). Higher WG intake is significantly inversely associated with BMI in observational studies but not RCTs up to 16 weeks in length; RCTs with longer intervention periods are warranted.

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Kevin Maki ◽  
Orsolya Palacios ◽  
Katie Koecher ◽  
Caleigh Sawicki ◽  
Kara Livingston ◽  
...  

Abstract Objectives To analyze data from observational studies and randomized controlled trials (RCTs) reporting on the relationship between whole grain (WG) intake and weight status. Methods A systematic literature search was conducted, using Ovid/Medline, to identify observational studies and RCTs assessing WG food intake and weight status in adults. Meta-regression analysis was used to derive pooled estimates from cross-sectional studies, and a meta-analysis with random effects modeling was used to derive pooled estimates from RCTs. Prospective cohort results were assessed qualitatively since differences in methods and outcomes prevented completion of a pooled analysis. Results Eleven publications (12 studies; 136,834 subjects) were included in the meta-regression analysis of cross-sectional data, 8 publications (9 studies; 973 subjects) were included in the meta-analysis of RCTs, and 6 publications were reviewed for qualitative assessment of prospective cohort data. RCT intervention lengths ranged from 12–16 weeks, and WG intake from foods ranged from 32–215 g/d in the WG intervention groups. Meta-regression of cross-sectional studies indicated a significant, inverse correlation between body mass index (BMI) and intake of WG from food: weighted slope −0.0141 kg/m2 per g/d [95% confidence interval (CI): −0.0207, −0.0077; r = −0.526, P = 0.0001]. Meta-analysis of data from RCTs showed a non-significant pooled standardized effect size of −0.049 kg (95% CI −0.297, 0.199, P = 0.698) for the mean difference in weight change for the WG intervention groups compared with controls. No significant differences were observed for secondary variables, including waist circumference and % body fat. Prospective cohort results generally showed inverse associations between weight change and baseline WG intake and change in WG intake over follow-up periods of 5 to 20 years. Conclusions Higher WG intake is significantly inversely associated with BMI in observational studies, but results from RCTs do not show an effect of WG intake on change in weight over periods of up to 16 weeks. RCTs with longer intervention periods are needed to further investigate the potential for WG intake to influence body weight and related anthropometrics. Funding Sources General Mills, Inc., Minneapolis, MN.


2021 ◽  
Vol 8 ◽  
Author(s):  
Zigang Liu ◽  
Yongmei Zhao ◽  
Ming Lei ◽  
Guancong Zhao ◽  
Dongcheng Li ◽  
...  

Objective: Randomized controlled trials (RCTs) evaluating the influence of remote ischemic preconditioning (RIPC) on acute kidney injury (AKI) after cardiac surgery showed inconsistent results. We performed a meta-analysis to evaluate the efficacy of RIPC on AKI after cardiac surgery.Methods: Relevant studies were obtained by search of PubMed, Embase, and Cochrane's Library databases. A random-effect model was used to pool the results. Meta-regression and subgroup analyses were used to determine the source of heterogeneity.Results: Twenty-two RCTs with 5,389 patients who received cardiac surgery −2,702 patients in the RIPC group and 2,687 patients in the control group—were included. Moderate heterogeneity was detected (p for Cochrane's Q test = 0.03, I2 = 40%). Pooled results showed that RIPC significantly reduced the incidence of AKI compared with control [odds ratio (OR): 0.76, 95% confidence intervals (CI): 0.61–0.94, p = 0.01]. Results limited to on-pump surgery (OR: 0.78, 95% CI: 0.64–0.95, p = 0.01) or studies with acute RIPC (OR: 0.78, 95% CI: 0.63–0.97, p = 0.03) showed consistent results. Meta-regression and subgroup analyses indicated that study characteristics, including study design, country, age, gender, diabetic status, surgery type, use of propofol or volatile anesthetics, cross-clamp time, RIPC protocol, definition of AKI, and sample size did not significantly affect the outcome of AKI. Results of stratified analysis showed that RIPC significantly reduced the risk of mild-to-moderate AKI that did not require renal replacement therapy (RRT, OR: 0.76, 95% CI: 0.60–0.96, p = 0.02) but did not significantly reduce the risk of severe AKI that required RRT in patients after cardiac surgery (OR: 0.73, 95% CI: 0.50–1.07, p = 0.11).Conclusions: Current evidence supports RIPC as an effective strategy to prevent AKI after cardiac surgery, which seems to be mainly driven by the reduced mild-to-moderate AKI events that did not require RRT. Efforts are needed to determine the influences of patient characteristics, procedure, perioperative drugs, and RIPC protocol on the outcome.


2006 ◽  
Vol 15 (4) ◽  
pp. 402-412 ◽  
Author(s):  
Anthony Limpus ◽  
Wendy Chaboyer ◽  
Ellen McDonald ◽  
Lukman Thalib

• Objective To systematically review the randomized trials, observational studies, and survey evidence on compression and pneumatic devices for thromboprophylaxis in intensive care patients. • Methods Published studies on the use of compression and pneumatic devices in intensive care patients were assessed. A meta-analysis was conducted by using the randomized controlled trials. • Results A total of 21 relevant studies (5 randomized controlled trials, 13 observational studies, and 3 surveys) were found. A total of 811 patients were randomized in the 5 randomized controlled trials; 3421 patients participated in the observational studies. Trauma patients only were enrolled in 4 randomized controlled trials and 4 observational studies. Meta-analysis of 2 randomized controlled trials with similar populations and outcomes revealed that use of compression and pneumatic devices did not reduce the incidence of venous thromboembolism. The pooled risk ratio was 2.37, indicative of favoring the control over the intervention in reducing the deep venous thrombosis; however, the 95% CI of 0.57 to 9.90 indicated no significant differences between the intervention and the control. A range of methodological issues, including bias and confounding variables, make meaningful interpretation of the observational studies difficult. • Conclusions The limited evidence suggests that use of compressive and pneumatic devices yields results not significantly different from results obtained with no treatment or use of low-molecular-weight heparin. Until large randomized controlled trials are conducted, the role of mechanical approaches to thromboprophylaxis for intensive care patients remains uncertain.


2020 ◽  
Vol 9 (6) ◽  
pp. 1788
Author(s):  
Karolina Skonieczna-Żydecka ◽  
Karolina Kaźmierczak-Siedlecka ◽  
Mariusz Kaczmarczyk ◽  
Joanna Śliwa-Dominiak ◽  
Dominika Maciejewska ◽  
...  

We aimed to systematically review the effectiveness of probiotic/synbiotic formulations to counteract cardiometabolic risk (CMR) in healthy people not receiving adjunctive medication. The systematic search (PubMed/MEDLINE/Embase) until 1 August 2019 was performed for randomized controlled trials in >20 adult patients. Random-effect meta-analysis subgroup and meta-regression analysis of co-primary (haemoglobin A1c (HbA1C), glucose, insulin, body weight, waist circumference (WC), body mass index (BMI), cholesterol, low-density lipoproteins (LDL), high-density lipoproteins (HDL), triglycerides, and blood pressure) and secondary outcomes (uric acid, plasminogen activator inhibitor-1–PAI-1, fibrinogen, and any variable related to inflammation/endothelial dysfunction). We included 61 trials (5422 persons). The mean time of probiotic administration was 67.01 ± 38.72 days. Most of probiotic strains were of Lactobacillus and Bifidobacterium genera. The other strains were Streptococci, Enterococci, and Pediococci. The daily probiotic dose varied between 106 and 1010 colony-forming units (CFU)/gram. Probiotics/synbiotics counteracted CMR factors (endpoint data on BMI: standardized mean difference (SMD) = −0.156, p = 0.006 and difference in means (DM) = −0.45, p = 0.00 and on WC: SMD = −0.147, p = 0.05 and DM = −1.21, p = 0.02; change scores on WC: SMD = −0.166, p = 0.04 and DM = −1.35, p = 0.03) in healthy persons. Overweight/obese healthy people might additionally benefit from reducing total cholesterol concentration (change scores on WC in overweight/obese: SMD: −0.178, p = 0.049). Poor quality of probiotic-related trials make systematic reviews and meta-analyses difficult to conduct and draw definite conclusions. “Gold standard” methodology in probiotic studies awaits further development.


2019 ◽  
Vol 78 (6) ◽  
pp. 474-485 ◽  
Author(s):  
Jeffery L Heileson

Abstract The American Heart Association (AHA) recently published a meta-analysis that confirmed their 60-year-old recommendation to limit saturated fat (SFA, saturated fatty acid) and replace it with polyunsaturated fat to reduce the risk of heart disease based on the strength of 4 Core Trials. To assess the evidence for this recommendation, meta-analyses on the effect of SFA consumption on heart disease outcomes were reviewed. Nineteen meta-analyses addressing this topic were identified: 9 observational studies and 10 randomized controlled trials. Meta-analyses of observational studies found no association between SFA intake and heart disease, while meta-analyses of randomized controlled trials were inconsistent but tended to show a lack of an association. The inconsistency seems to have been mediated by the differing clinical trials included. For example, the AHA meta-analysis only included 4 trials (the Core Trials), and those trials contained design and methodological flaws and did not meet all the predefined inclusion criteria. The AHA stance regarding the strength of the evidence for the recommendation to limit SFAs for heart disease prevention may be overstated and in need of reevaluation.


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