[How to interpret the certainty of evidence based on GRADE (Grading of Recommendations, Assessment, Development and Evaluation)]. / Wie sich die Vertrauenswürdigkeit von Evidenz anhand von GRADE ("grading of recommendations, assessment, development and evaluation") interpretieren lässt.

BACKGROUND: GRADE (Grading of Recommendations, Assessment, Development and Evaluation) is a widely used approach in the fields of medicine and public health to assess the outcome-specific certainty of the evidence in systematic reviews. OBJECTIVES: To make the GRADE approach comprehensible in order to facilitate the reading, understanding and interpretation of GRADE assessments in systematic reviews. MATERIALS AND METHODS: Presentation of the procedure of the GRADE approach using the example of a Cochrane review on selenium supplements in the prevention of prostate cancer. RESULTS: GRADE provides criteria for rating the certainty of evidence. GRADE's approach to rating the certainty of the evidence is based on a four-level system (high, moderate, low, very low). The GRADE approach classifies bodies of randomized controlled trials as initially starting at high certainty and bodies of observational studies at initially starting at low certainty. By assessing the five domains (risk for bias, inconsistency, indirectness, insufficient precision and publication bias), certainty can be rated down or, in the case of large effects, existing dose-response relationships or plausible confounders, rated up. CONCLUSIONS: GRADE is a consistent and transparent approach for rating the certainty of a body of evidence by offering explicit key questions.

Breakfast quality and cardiometabolic risk profiles in an upper middle-aged German population.

BACKGROUND/OBJECTIVES: Little is known about relation of overall breakfast quality with cardiometabolic risk factors. Therefore, this study aimed to explore sex-specific associations between breakfast quality and cardiometabolic risk profiles in a sample of an upper middle-aged German population. SUBJECTS/METHODS: Cardiometabolic profiles of 339 men and 329 women were cross-sectionally assessed using an overall biomarker score (BScore), glycated hemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), blood pressure, body mass index (BMI) and waist circumference (WC). Overall breakfast quality was assessed by using (i) an a-priori defined breakfast quality score (BQS) and (ii) data-driven breakfast patterns based on principal component analysis (PCA). Multiple linear regression models for association of breakfast quality with all outcomes were adjusted for all potential confounders including overall diet quality. RESULTS: After adjustment for all potential confounders the BQS was inversely associated with the BScore (regression beta with 95% Confidence Interval: -0.29 (052-0.06)) and HbA1c (-0.12 (-0.21, -0.04)) in men; whereas no such associations were observed in women. Four breakfast (B) patterns were identified: B-processed-food pattern, B-cereal pattern, B-high fat pattern and B-dairy & cereal pattern. The B-processed-food pattern was positively associated with HbA1c (0.09(0.01, 0.18)), BMI (0.16 (0.06, 0.26)), and WC (0.17 (0.8, 0.26)) in men, and BMI (0.13 (0.1, 0.25)) and WC (0.11(0.01.0.22)) in women. The B-cereal pattern was inversely associated with BScore (-0.23 (-0.45, -0.01)) and BMI (-0.11 (-0.20, -0.01)) in men and WC(-0.16 (-0.27, -0.05)) in women. The B-dairy & cereal pattern was also inversely associated with BScore (-0.26 (-0.48, -0.04)) in men but not in women. CONCLUSIONS: The overall breakfast quality was cross-sectionally associated with a healthier cardiometabolic profile, especially in upper-middle age men, independent of overall dietary quality. Such analyses should be supplemented by studies investigating the circadian sequence of food intake and metabolic consequences including hard disease endpoints.

Olive oil in the prevention and management of type 2 diabetes mellitus: a systematic review and meta-analysis of cohort studies and intervention trials.

BACKGROUND/OBJECTIVES: Olive oil (OO) as food is composed mainly of fatty acids and bioactive compounds depending from the extraction method. Both had been discussed as health promoting with still open questions. Thus, we conducted a meta-analysis to illustrate the impact of this food on type 2 diabetes (T2D) by investigating the association between OO intake and risk of T2D, and the effect of OO intake in the management of T2D. SUBJECTS/METHODS: Searches were performed in PubMed, Cochrane Library and google scholar. First, we conducted a random effect meta-analysis of prospective cohort studies and trials investigating the association between OO and risk of T2D. Second, a meta-analysis was performed to detect the effects of olive oil on glycemic control in patients with T2D. RESULTS: Four cohort studies including 15 784 T2D cases and 29 trials were included in the meta-analysis. The highest OO intake category showed a 16% reduced risk of T2D (RR: 0.84; 95% CI: 0.77, 0.92) compared with the lowest. However, we observed evidence for a nonlinear relationship. In T2D patients OO supplementation resulted in a significantly more pronounced reduction in HbA1c (MD: -0.27%; 95% CI: -0.37, -0.17) and fasting plasma glucose (MD: -0.44 mmol l-1; 95% CI -0.66, -0.22) as compared with the control groups. CONCLUSIONS: This meta-analysis provides evidence that the intake of OO could be beneficial for the prevention and management of T2D. This conclusion regards OO as food, and might not been valid for single components comprising this food.

Synchronic inverse seasonal rhythmus of energy density of food intake and sleep quality: a contribution to chrono-nutrition from a Polish adult population.

BACKGROUND/OBJECTIVES: There is evidence which suggests that sleep behavior and dietary intake are interlinked. Thus, we investigated whether a seasonal rhythm in food-energy density exists, and how this relates to quality of sleep. SUBJECTS/METHODS: Two hundred and thirty adult volunteers were investigated across the four seasons. Anthropometrical measurements were obtained and The Pittsburgh Sleep Quality Index was used for an assessment of sleep quality and disturbances. The dietary intake was evaluated using a 24 h dietary recall. Generalized estimating equations were used to estimate seasonal changes in energy density and sleep quality, as well as the association of energy density with sleep quality. All analyses were adjusted for age, sex, education, occupation and shift-work. RESULTS: Mean food energy density was significantly higher in winter as compared with other seasons (P<0.05), although no seasonal variations were observed in macronutrient intake (fat and protein). Overall, the sleep quality was low (score value >5) in all seasons, with the lowest quality occurring in winter and the highest in spring (P<0.05). The components of sleep quality score showed that winter had statistically (P<0.05) poorer subjective sleep quality, sleep latency and sleep disturbances, but lower daytime dysfunction compared with spring and summer. After adjusting for seasonal effects (correlated outcome data) and shift-work, energy density was found to be inversely associated (P<0.0001) with sleep quality. CONCLUSIONS: An inverse association between seasonal fluctuation of food energy density and sleep quality was found with winter time, associated with the intake of higher energy dense food products and the lowest sleep quality.

Effect of plant-based diets on obesity-related inflammatory profiles: a systematic review and meta-analysis of intervention trials.

Plant-based dietary interventions have been proposed to reduce obesity induced chronic low-grade inflammation and hence prevent chronic disease risk; however, human evidence remains unclear. This systematic review and meta-analysis of intervention trials aimed to assess the effect of plant-based diets on obesity-related inflammatory biomarker profiles. Medline, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for articles published until January 2016 and mean differences in biomarkers of inflammatory status were assessed for: C-reactive protein (CRP), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-ɑ), soluble intercellular adhesion molecule 1 (sICAM), leptin, adiponectin and resistin. Of initially identified 2,583 publications, 29 met the meta-analysis inclusion criteria [a total of 2,689 participants]. Consumption of plant-based diets was associated with a reduction in the mean concentrations of the following biomarkers: CRP [effect size, -0.55 mg/l, 95% confidence intervals (CI): -0.78; -0.32, I2 = 94.4%], IL-6 [effect size, -0.25 ng/l, 95% CI: -0.56; 0.06, I2 = 74%], and, to some degree, sICAM (-25.07 ng/ml [95% CI: -52.32; 2.17, I2 = 93.2%]). No substantial effects were revealed for TNF-ɑ, resistin, adiponectin and leptin. Plant-based diets are associated with an improvement in obesity-related inflammatory profiles and could provide means for therapy and prevention of chronic disease risk.

Meal patterns across ten European countries - results from the European Prospective Investigation into Cancer and Nutrition (EPIC) calibration study.

OBJECTIVE: To characterize meal patterns across ten European countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) calibration study. DESIGN: Cross-sectional study utilizing dietary data collected through a standardized 24 h diet recall during 1995-2000. Eleven predefined intake occasions across a 24 h period were assessed during the interview. In the present descriptive report, meal patterns were analysed in terms of daily number of intake occasions, the proportion reporting each intake occasion and the energy contributions from each intake occasion. SETTING: Twenty-seven centres across ten European countries. SUBJECTS: Women (64 %) and men (36 %) aged 35-74 years (n 36 020). RESULTS: Pronounced differences in meal patterns emerged both across centres within the same country and across different countries, with a trend for fewer intake occasions per day in Mediterranean countries compared with central and northern Europe. Differences were also found for daily energy intake provided by lunch, with 38-43 % for women and 41-45 % for men within Mediterranean countries compared with 16-27 % for women and 20-26 % for men in central and northern European countries. Likewise, a south-north gradient was found for daily energy intake from snacks, with 13-20 % (women) and 10-17 % (men) in Mediterranean countries compared with 24-34 % (women) and 23-35 % (men) in central/northern Europe. CONCLUSIONS: We found distinct differences in meal patterns with marked diversity for intake frequency and lunch and snack consumption between Mediterranean and central/northern European countries. Monitoring of meal patterns across various cultures and populations could provide critical context to the research efforts to characterize relationships between dietary intake and health.

Effects of leucine-rich protein supplements on anthropometric parameter and muscle strength in the elderly: a systematic review and meta-analysis.

OBJECTIVE: The primary objective of the present systematic review and meta-analysis was to synthesize the available literature relating to leucine supplementation in the elderly with respect to its effects on anthropometrical parameters and muscle strength. The secondary aim was to perform a selective subgroup analysis when possible differentiating between healthy and sarcopenic subjects. METHODS: Literature search was performed using the electronic databases MEDLINE, EMBASE, SportDiscus, and the Cochrane Central Register of trials with restrictions to randomized controlled trials or studies following a cross-over design. Parameters taken into account were body weight, body mass index, lean body mass, fat mass, percentage of body fat, hand grip strength, and knee extension strength. Moreover, biomarkers of glucose metabolism (fasting glucose, fasting insulin, albumin, and HOMA index) were extracted when possible. For each outcome measure of interest, a meta-analysis was performed in order to determine the pooled effect of the intervention in terms of weighted mean differences between the post-intervention (or differences in means) values of the leucine and the respective control groups. Data analysis was performed using the Review Manager 5.2.4. software. RESULTS: A total of 16 studies enrolling 999 subjects met the inclusion criteria. Compared with control groups, leucine supplementation significantly increased gain in body weight [mean differences 1.02 kg, 95%-CI (0.19, 1.85), p=0.02], lean body mass [mean differences 0.99 kg, 95%-CI (0.43, 1.55), p=0.0005], and body mass index [mean differences 0.33 kg/m2, 95%-CI (0.13, 0.53), p=0.001], when compared to the respective control groups. With respect to body weight and lean body mass, leucine supplementation turned out to be more effective in the subgroup of study participants with manifested sarcopenia. All other parameters under investigation were not affected by leucine supplementation in a fashion significantly different from controls. CONCLUSIONS: It is concluded that leucine supplementation was found to exert beneficial effects on body weight, body mass index, and lean body mass in older persons in those subjects already prone to sarcopenia, but not muscle strength. However, due to the heterogeneity between the trials included in this systematic review, further studies adopting a homogenous design with respect to participant characteristics duration as well as the kind and amount of daily supplement in use are required.

Mediterranean dietary pattern, inflammation and endothelial function: a systematic review and meta-analysis of intervention trials.

BACKGROUND: High adherence to a Mediterranean diet (MD) is associated with reduced all-cause and cardiovascular mortality risk. To our knowledge, there is no systematic review and meta-analysis of randomized controlled trials that has compared the effects of an MD on outcomes of endothelial function and inflammation. METHODS AND RESULTS: Literature search was performed using the electronic databases MEDLINE, EMBASE, and the Cochrane Trial Register. Inclusion criteria were: randomized controlled trials, 19 + years of age, and minimum intervention period of 12 weeks. Study specific weighted mean differences (WMD) were pooled using a random effect model. Seventeen trials including 2300 subjects met the objectives. MD regimens resulted in a significantly more pronounced increase in flow mediated dilatation [WMD: 1.86%, 95% CI 0.23 to 3.48, p = 0.02; I(2) = 43%], and adiponectin [WMD: 1.69 µg/ml, 95% CI 0.27 to 3.11, p = 0.02; I(2) = 78%], while high-sensitive C reactive protein [WMD: -0.98 mg/l, 95% CI -1.48 to -0.49, p < 0.0001; I(2) = 91%], interleukin-6 [WMD: -0.42 pg/ml, 95% CI -0.73 to -0.11, p = 0.008; I(2) = 81%], and intracellular adhesion molecule-1 [WMD: -23.73 ng/ml, 95% CI -41.24 to -6.22 p = 0.008; I(2) = 34%] turned out to be significantly more decreased. CONCLUSION: The results of the present meta-analysis provide evidence that an MD decreases inflammation and improves endothelial function.

Long-term effects of low glycemic index/load vs. high glycemic index/load diets on parameters of obesity and obesity-associated risks: a systematic review and meta-analysis.

AIM: The aim of the present meta-analysis was to investigate the long-term effects of glycemic index-related diets in the management of obesity with a special emphasis on the potential benefits of low glycemic index/load (GI/GL) in the prevention of obesity-associated risks. DATA SYNTHESIS: Electronic searches for randomized controlled trials (RCTs) comparing low glycemic index/load versus high glycemic index/load diets were performed in MEDLINE, EMBASE and the Cochrane Library. Outcome of interest markers included anthropometric data as well as biomarkers of CVD and glycemic control. Study specific weighted mean differences were pooled using a random effect model. 14 studies were included in the primary meta-analysis. Weighted mean differences in change of C-reactive protein [WMD: -0.43 mg/dl, (95% CI -0.78 to -0.09), p = 0.01], and fasting insulin [WMD: -5.16 pmol/L, (95% CI -8.45 to -1.88), p = 0.002] were significantly more pronounced in benefit of low GI/GL diets. However decrease in fat free mass [WMD: -1.04 kg (95% CI -1.73 to -0.35), p = 0.003] was significantly more pronounced following low GI/GL diets as well. No significant changes were observed for blood lipids, anthropometric measures, HbA1c and fasting glucose. Sensitivity analysis was performed for RCTs excluding subjects with type 2 diabetes. Decreases in C-reactive protein and fasting insulin remained statistically significant in the low GI/GL subgroups. CONCLUSIONS: The present systematic review provides evidence for beneficial effects of long-term interventions administering a low glycemic index/load diet with respect to fasting insulin and pro-inflammatory markers such as C-reactive protein which might prove to be helpful in the primary prevention of obesity-associated diseases.

Effects of monounsaturated fatty acids on cardiovascular risk factors: a systematic review and meta-analysis.

The appropriate pattern of macronutrient distribution for dietary protocols aimed at treating or preventing obesity and its associated cardiovascular diseases is still a controversial topic of discussion. Recommendations considering a specific percentage or range for monounsaturated fatty acids (MUFA) are rare. It was the aim of this study to analyze long-term, randomized, controlled dietary intervention trials and to investigate the effects of MUFA on the biomarkers of obesity and cardiovascular risk factors. Dietary regimens with a high amount of MUFA (>12%) were compared to those with ≤12%. The biomarkers taken into account were weight, waist circumference, fat mass, total cholesterol, LDL cholesterol, HDL cholesterol, triacylglycerols, systolic and diastolic blood pressure, as well as C-reactive protein. A total of 12 studies met the inclusion criteria. Data analysis was performed using the Review Manager 5.0.25 software. Significant differences between high- and low-MUFA protocols could be observed with respect to fat mass [-1.94 kg (confidence interval -3.72, -0.17), p = 0.03], systolic blood pressure [-2.26 mm Hg (confidence interval -4.28, -0.25), p = 0.03] and diastolic blood pressure [-1.15 mm Hg (confidence interval -1.96, -0.34), p = 0.005] favoring the dietary protocols with >12% MUFA. Therefore, MUFA might represent a useful tool in the design of dietary regimens for obesity and cardiovascular disease.

Effects of monounsaturated fatty acids on glycaemic control in patients with abnormal glucose metabolism: a systematic review and meta-analysis.

BACKGROUND/AIMS: In 2008, the American Diabetes Association recommended low-carbohydrate or low-fat diets for weight management in patients with established type 2 diabetes (T2D), while the amount of monounsaturated fatty acids (MUFA) was not specified. This systematic review focused on the effects of diets high in MUFA versus diets low in MUFA on important risk factors of T2D (i.e. plasma glucose, insulin, homeostasis model assessment of insulin resistance and glycosylated haemoglobin, HbA1c). METHODS: Nine randomized controlled intervention trials with a total of 1,547 participants and a running time of at least 6 months, comparing diets high versus low in MUFA among adults with abnormal glucose metabolism (T2D, impaired glucose tolerance and insulin resistant), being overweight or obese, have been included in the meta-analysis. We performed a random effects meta-analysis to determine the weighted mean differences with 95% confidence intervals using the software package Review Manager 5.0.25 of the Cochrane Collaboration. RESULTS: Significant differences in HbA1c were found (weighted mean difference -0.21%, 95% CI -0.40 to -0.02; p = 0.03), favouring the high MUFA groups. In contrast, fasting plasma glucose, fasting plasma insulin as well as the homeostasis model assessment of insulin resistance were not affected by the amounts of MUFA in the dietary protocols. CONCLUSIONS: In summary, this systematic review found that high MUFA diets appear to be effective in reducing HbA1c, and therefore, should be recommended in the dietary regimes of T2D.