Structured triglyceride for parenteral nutrition: meta-analysis of randomized controlled trials

This study assessed the safety and efficacy of structured triglyceride (ST) for parenteral nutrition. A meta-analysis of all the relevant randomized controlled trials (RCTs) was performed. Clinical trials were identified from the following electronic databases: MEDLINE, EMBASE, the Cochrane Controlled Trials Register, Chinese Bio-medicine Database. The search was undertaken in March 2005. Language was restricted to Chinese and English. Literature references were checked at the same time. Only RCTs were extracted and evaluated by two reviewers independently of each other. The statistical analysis was performed by RevMan4.2 software which was provided by the Cochrane Collaboration. A P value of <0.05 was considered statistically significant. Ten RCTs involving 236 patients were included. Eight of them compared ST with the long-chain triglyceride (LCT), and the combined results showed that the ST had significant effect on resting energy expenditure (weighted mean difference [WMD] =1.54, 95%CI [ 1.26, 1.82], p<0.00001), plasma glycerol (WMD = 0.14, 95%CI [0.06, 0.22], P= 0.0007), free fatty acids (WMD=0.24, 95%CI [0.10, 0.37], P=0.0006), and beta-hydroxybutyric acid (WMD=0.14, 95%CI [0.06, 0.22], P=0.0007), but no differences was found regarding nitrogen balance (standardized mean difference [SMD] = 0.64, 95%CI [-0.30, 1.59], P=0.18), respiratory quotient (WMD =-0.02, 95%CI [-0.04, 0.01], P= 0.18), and plasma triglycerides (WMD = -0.10, 95%CI [-0.30, 0.10], P=0.32). Only two RCTs compared ST with the physical mixture of medium- and long-chain triglyceride (MCT/LCT), data from trials were not combined due to clinical differences between trials, and conclusions can not be drew from the present data. ST appeared to be safe and well tolerated. Further trials are required, especially compared with the MCT/LCT, with sufficient size and rigorous design.     

健康教育对人群体质指数的控制作用

目的　探索以社区为基础的健康教育和健康促进对人群的体质指数、超重或肥胖的影响。方法　于 1991～ 2 0 0 0年期间在北京、上海和长沙三城市各选取 10万社区人群 ,随机分为干预和对照社区各 5万人群。在干预社区开展多种形式的健康教育和健康促进活动 ,评价干预和对照两社区人群KAB水平和体质指数变化。结果　与 1992年基线调查相比 ,在三城市人群和不同目标人群的干预对对照组KAB水平、人群经常运动比率的净提高 ,在统计学上有显著性差异。对照组在全人群体质指数、超重率和肥胖率上升趋势高于干预组 ,其干预对对照组的净降低在统计学上有显著性差异。结论　健康教育和健康促进可有效控制人群体质指数的上升 ,对人群预防心脑血管病具有重要的意义。     

The effect of coffee consumption on serum lipids: a meta-analysis of randomized controlled trials

Background/objectives:Numbers of epidemiological studies assessing coffee consumption and serum lipids have yielded inconsistent results. We aimed to evaluate the effects of coffee intake on serum lipids.Subjects/methods:We searched several English and Chinese electronic databases up to September 2011 for randomized controlled trials of coffee on serum lipids. Weighted mean effect size was calculated for net changes in serum lipids by using random-effect models or fixed-effect models. Subgroup and meta-regression analyses were conducted to explore possible explanations for heterogeneity among trials.Results:Twelve studies conducted in Western countries with a total of 1017 subjects were identified. Meta-analyses showed, on average, drinking coffee for 45 days was associated with an increase of 8.1?mg/dl (95% confidence interval (CI): 4.5, 11.6; P<0.001) for total cholesterol (TC), 5.4?mg/dl (95% CI: 1.4, 9.5; P=0.009) for low-density lipoprotein cholesterol (LDL-C) and 12.6?mg/dl (95% CI: 3.5, 12.6; P=0.007) for triglyceride (TG). The increase in TC were greater in trials using unfiltered coffee and caffeinated coffee as the treatment group. Those who had hyperlipidemia were more sensitive to the cholesterol-raising effect of coffee. Meta-regression analysis revealed a positive dose-response relation between coffee intake and TC, LDL-C and TG.Conclusion:The intake of coffee especially unfiltered coffee is contributed significantly to the increase in TC, LDL-C and TG, and the changes were related to the level of intake. Studies of coffee intake on serum lipids in Asian populations should be performed.     

Effect of probiotics on body weight and body-mass index: a systematic review and meta-analysis of randomized,controlled trials

Objective: To assess the efficacy of probiotic therapies on body weight and BMI using a meta-analysis of randomized, controlled trials.

Methods: Twenty studies with 25 trials (1931 participants with age over 18 years) were included. The pooled WMD was calculated by random effects model.

Results: Probiotic consumption significantly reduced body weight by 0.59?kg (95% CI, 0.30–0.87) and BMI by 0.49?kg/m² (95% CI, 0.24–0.74). A greater reduction in BMI was found with multiple species of probiotics. Subgroup analysis of trials with intervention duration ≥8 weeks found a more significant reduction in BMI. Limiting analysis to trials with a baseline BMI ≥25?kg/m² showed a greater reduction in BMI.

Conclusion: Consuming probiotics could reduce body weight and BMI, with a potentially greater effect when multiple species of probiotics were consumed, the duration of intervention was ≥8 weeks, or the objects were overweight.     

The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trials

Recent animal studies have suggested that grape seed extract has beneficial effects on the cardiovascular system. Randomized trials in human beings have yielded conflicting results. The objective of this systematic review was to assess the effect of grape seed extract on changes in blood pressure, heart rate, lipid levels, and C-reactive protein (CRP) levels. We searched MEDLINE (January 1, 1950, through October 31, 2010), Agricola (January 1, 1970, through October 31, 2010), Scopus (January 1, 1996, through October 31, 2010), and the Cochrane Central Register of Controlled Trials (through October 31, 2010) for randomized controlled trials in human beings of grape seed extract reporting efficacy data on at least one of the following end points: systolic or diastolic blood pressure, heart rate, total cholesterol, low-density or high-density lipoprotein cholesterol, triglycerides, or CRP. A manual search of references from primary and review articles was performed to identify additional relevant trials. For all endpoints except CRP, the mean change in each parameter from baseline was treated as a continuous variable and the effect size was calculated as the weighted mean difference between the means in the grape seed extract and control groups. Data on CRP were pooled as a standardized mean difference. Nine randomized, controlled trials (N=390) met the inclusion criteria, and a meta-analysis was conducted. Upon meta-analysis, grape seed extract significantly lowered systolic blood pressure (weighted mean difference −1.54 mm Hg (95% confidence interval −2.85 to −0.22, P=0.02]), and heart rate (weighted mean difference −1.42 bpm (95% confidence interval −2.50 to −0.34, P=0.01]). No significant effect on diastolic blood pressure, lipid levels, or CRP was found. No statistical heterogeneity was observed for any analysis (I²<39% for all). Egger's weighted regression statistic suggested low likelihood of publication bias in all analysis (P>0.05 for all), except for the effect on diastolic blood pressure (P=0.046). Based on the currently available literature, grape seed extract appears to significantly lower systolic blood pressure and heart rate, with no effect on lipid or CRP levels. Larger randomized, double-blinded trials evaluating different dosages of grape seed extract and for longer follow-up durations are needed.     

Can dietary interventions change diet and cardiovascular risk factors? A meta-analysis of randomized controlled trials.

OBJECTIVES: This study evaluated the effectiveness of dietary advice in primary prevention of chronic disease. METHODS: A meta-analysis was conducted of 17 randomized controlled trials of dietary behavior interventions of at least 3 months' duration. Results were analyzed as changes in reported dietary fat intakes and biomedical measures (serum cholesterol, urinary sodium, systolic and diastolic blood pressure) in the intervention group minus changes in the control group at 3 to 6 months and 9 to 18 months of follow-up. RESULTS: After 3 to 6 months, mean net changes in each of the five outcomes favored intervention. For dietary fat as a percentage of food energy, the change was -2.5% (95% confidence interval [CI] = -3.9%, -1.1%). Mean net changes over 9 to 18 months were as follows: serum cholesterol, -0.22 (95% CI = -0.39, -0.05) mmol/L; urinary sodium, -45.0 (95% CI = -57.1, -32.8) mmol/24 hours; systolic blood pressure, -1.9 (95% CI = -3.0, 0.8) mm Hg; and diastolic blood pressure, -1.2 (95% CI = -2.6, 0.2) mm Hg. CONCLUSIONS: Individual dietary interventions in primary prevention can achieve modest improvements in diet and cardiovascular disease risk status that are maintained for 9 to 18 months.     

A systematic review of effect of prenatal zinc supplementation on birthweight: meta-analysis of 17 randomized controlled trials

The effect of prenatal zinc supplementation on birthweight is controversial as randomized controlled trials (RCTs) report conflicting conclusions. A systematic review which includes meta-analysis was done on 17 RCTs conducted worldwide since 1984 to assess the effect of prenatal zinc supplementation on birthweight. The studies were identified through web-based search. Heterogeneity among studies was assessed using Cochrane Q test statistic. Effect-size was measured based on standardized mean difference. Pooled effect-size was computed using a variant of random effect model. Thirteen of the 17 RCTs found no association, three reported positive association, and one reported negative association. Based on fixed and random effect models, the pooled effect-sizes were 0.0268 [95% confidence interval (CI) 0.0764, -0.0229) and 0.0712 (95% CI 0.1619, -0.0194) respectively. The effect-size estimate remains insignificant after stratification was made based on the dose of supplementation (optimal vs high dose), type of study (community vs institution-based), and type of source country (developed vs developing). The meta-analysis did not witness any association between birthweight and prenatal zinc supplementation.     

Effect of long-term community health education on body mass index. The Stanford Five-City Project

Being overweight is a risk factor for cardiovascular heart disease and other medical problems. The purpose of this study was to examine the effect of a community-wide cardiovascular risk reduction trial (the Stanford Five-City Project) on body mass index. In the Stanford Five-City Project, two treatment cities (n = 122,800) received a 6-year mass media and community organization cardiovascular risk reduction intervention. Changes in the treatment cities were compared with two control cities (n = 197,500) for changes in knowledge of risk factors, blood pressure, plasma cholesterol level, smoking rate, body mass index, and resting pulse rate after 5-1/3 years of the education program. Both cohort and cross-sectional (independent) samples were used in the study. In the independent surveys, subjects in the treatment communities gained significantly less weight than subjects in the control communities (0.57 kg compared with 1.25 kg) over 6 years. In the cohort, there were no significant overall differences. The study provides some evidence that a community health education program may help reduce weight gain over time, but more effective methods must be developed if this important risk factor is to be favorably affected in broad populations.     

维生素E补充对心脑血管疾病影响随机对照试验meta分析

目的 探讨维生素E补充剂对心脑血管疾病事件(中风、心肌梗死、短暂性脑缺血发作)发生的影响,为心脑血管疾病的防治提供参考依据。方法 检索Pubmed、EMBASE、OVID、Healthstar、Cochrane database、Google Scholar、Science Citation Index等外文数据库和万方数据知识平台、中国知网系列数据库、中国生物医学文献数据库、维普期刊资源整合服务系统等中文数据库,全面收集1980-2014年间维生素E补充与心脑血管疾病事件发生关系的随机对照试验文献,采用Revman 5.1软件对纳入的文献进行Meta分析。结果 最终纳入13篇英文文献,累计维生素E组干预人数62871例,安慰剂组对照人数62837例;Meta分析结果显示,维生素E补充对心脑血管疾病事件的发生无显著影响(RR=0.99,95% CI=0.96~1.02),对中风的发生无显著影响(RR=1.03,95% CI=0.96~1.10),对心肌梗死的发生无显著影响(RR=0.99,95% CI=0.93~1.04),对短暂性脑缺血发作无显著影响(RR=0.94,95% CI=0.82~1.09);亚组分析结果显示,性别、随访时间、是否有其他干预措施和维生素E的剂量均对心脑血管疾病事件的发生无显著影响(均P>0.05)。结论 补充维生素E对心脑血管疾病事件的发生无显著影响。     

Effects of selenium supplements on cancer prevention: meta-analysis of randomized controlled trials

This meta-analysis aimed to investigate the preventive effect of selenium supplements alone on cancer as reported by randomized controlled trials (RCTs). We searched PubMed, EMBASE, and the Cochrane Library in July 2009. Of the 461 articles searched, 8 articles on 9 RCTs, which included 152,538 total participants, 32,110 in antioxidant supplement groups, and 120,428 in placebo groups, were included. In a random-effects meta-analysis of all 9 RCTs, selenium supplementation alone was found to have an overall preventive effect on cancer incidence [relative risk (RR) = 0.76; 95% confidence interval (CI) = 0.58-0.99]. Among subgroup meta-analyses, the preventive effect of selenium supplementation alone on cancer was apparently observed in populations with a low baseline serum selenium level (<125.6 ng/mL) (RR = 0.64; 95% CI = 0.53 to 0.78; I(2) = 45.5%; n = 7) and in high-risk populations for cancer (RR = 0.68; 95% CI = 0.58 to 0.80; I(2) = 41.5%; n = 8). The meta-analysis of randomized controlled trials indicates that there is possible evidence to support the use of selenium supplements alone for cancer prevention in the low baseline serum selenium level population and in the high-risk population for cancer.     

Sensitivity of effect variables in rheumatoid arthritis: A meta-analysis of 130 placebo controlled NSAID trials controlled NSAID trials

In a meta-analysis of placebo controlled NSAID trials, the sensitivity of the effect variables was calculated as the correlation coefficient and as the difference between drug and placebo, divided by the placebo group standard deviation. The patient's global evaluation was the most sensitive variable overall. Pain was more sensitive than Ritchie's index. Several variables may be omitted from clinical trials, especially if two active drugs are being compared. For example, the best maximum estimate for the difference in ESR between NSAADs and placebo was 1.0 mm/hr (95% confidence interval −1.5 to 3.4 mm/hr), and for joint size 0.44% (−1.0 to 1.9%), corresponding to a quarter of a millimeter for each of the 10 joints usually measured. It is suggested to record only the patient's global evaluation, pain, and morning stiffness.     

Effects of beta-carotene supplements on cancer prevention: meta-analysis of randomized controlled trials

This meta-analysis aimed to investigate the effects of beta-carotene supplements alone on cancer prevention as reported by randomized controlled trials (RCTs). We searched PubMed, EMBASE, and CENTRAL. Among the 848 articles searched, 6 randomized controlled trials, including 40,544 total participants, 20,290 in beta-carotene supplement groups, and 20,254 in placebo groups, were included in the final analysis. In a meta-analysis of 6 RCTs, beta-carotene supplements had no preventive effect on either cancer incidence [relative risk (RR) = 1.08, 95% confidence interval (CI) = 0.99-1.18] or cancer mortality (RR = 1.00, 95% CI = 0.87-1.15). Similar findings were observed in both primary prevention trials and secondary prevention trials. Subgroup analyses by various factors revealed no preventive effect of beta-carotene supplementation on cancer prevention and that it significantly increased the risk of urothelial cancer, especially bladder cancer (RR = 1.52, 95% CI = 1.03-2.24) and marginally increased the risk of cancer among current smokers (RR = 1.07, 95% CI = 0.99-1.17). The current meta-analysis of RCTs indicated that there is no clinical evidence to support the overall primary or secondary preventive effect of beta-carotene supplements on cancer. The potential effects, either beneficial or harmful, of beta-carotene supplementation on cancer should not be overemphasized.