Systematic reviews and meta-analyses are essential to summarize evidence relating to efficacy and safety of health care interventions accurately and reliably. The clarity and transparency of these reports, however, is not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users.

Since the development of the QUOROM (QUality Of Reporting Of Meta-analysis) Statement—a reporting guideline published in 1999—there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realizing these issues, an international group that included experienced authors and methodologists developed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions.

The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this Explanation and Elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA Statement, this document, and the associated Web site (http://www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

/pdf/the-prisma-statement-for-reporting-systematic-reviews-and-3j53e5oe33.pdf

The PRISMA Statement for Reporting Systematic Reviews and Meta-Analyses of Studies That Evaluate Health Care Interventions: Explanation and Elaboration

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Systematic reviews and meta-analyses are essential to summarise evidence relating to efficacy and safety of healthcare interventions accurately and reliably. The clarity and transparency of these reports, however, are not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users. Since the development of the QUOROM (quality of reporting of meta-analysis) statement—a reporting guideline published in 1999—there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realising these issues, an international group that included experienced authors and methodologists developed PRISMA (preferred reporting items for systematic reviews and meta-analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions. The PRISMA statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this explanation and elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA statement, this document, and the associated website (www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

/pdf/the-prisma-statement-for-reporting-systematic-reviews-and-48ibbzju0k.pdf

The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration

Machine Learning is the study of methods for programming computers to learn. Computers are applied to a wide range of tasks, and for most of these it is relatively easy for programmers to design and implement the necessary software. However, there are many tasks for which this is difficult or impossible. These can be divided into four general categories. First, there are problems for which there exist no human experts. For example, in modern automated manufacturing facilities, there is a need to predict machine failures before they occur by analyzing sensor readings. Because the machines are new, there are no human experts who can be interviewed by a programmer to provide the knowledge necessary to build a computer system. A machine learning system can study recorded data and subsequent machine failures and learn prediction rules. Second, there are problems where human experts exist, but where they are unable to explain their expertise. This is the case in many perceptual tasks, such as speech recognition, hand-writing recognition, and natural language understanding. Virtually all humans exhibit expert-level abilities on these tasks, but none of them can describe the detailed steps that they follow as they perform them. Fortunately, humans can provide machines with examples of the inputs and correct outputs for these tasks, so machine learning algorithms can learn to map the inputs to the outputs. Third, there are problems where phenomena are changing rapidly. In finance, for example, people would like to predict the future behavior of the stock market, of consumer purchases, or of exchange rates. These behaviors change frequently, so that even if a programmer could construct a good predictive computer program, it would need to be rewritten frequently. A learning program can relieve the programmer of this burden by constantly modifying and tuning a set of learned prediction rules. Fourth, there are applications that need to be customized for each computer user separately. Consider, for example, a program to filter unwanted electronic mail messages. Different users will need different filters. It is unreasonable to expect each user to program his or her own rules, and it is infeasible to provide every user with a software engineer to keep the rules up-to-date. A machine learning system can learn which mail messages the user rejects and maintain the filtering rules automatically. Machine learning addresses many of the same research questions as the fields of statistics, data mining, and psychology, but with differences of emphasis. Statistics focuses on understanding the phenomena that have generated the data, often with the goal of testing different hypotheses about those phenomena. Data mining seeks to find patterns in the data that are understandable by people. Psychological studies of human learning aspire to understand the mechanisms underlying the various learning behaviors exhibited by people (concept learning, skill acquisition, strategy change, etc.).

Machine learning

There is increasing evidence that genome-wide association ( GWA) studies represent a powerful approach to the identification of genes involved in common human diseases. We describe a joint GWA study ( using the Affymetrix GeneChip 500K Mapping Array Set) undertaken in the British population, which has examined similar to 2,000 individuals for each of 7 major diseases and a shared set of similar to 3,000 controls. Case-control comparisons identified 24 independent association signals at P < 5 X 10(-7): 1 in bipolar disorder, 1 in coronary artery disease, 9 in Crohn's disease, 3 in rheumatoid arthritis, 7 in type 1 diabetes and 3 in type 2 diabetes. On the basis of prior findings and replication studies thus-far completed, almost all of these signals reflect genuine susceptibility effects. We observed association at many previously identified loci, and found compelling evidence that some loci confer risk for more than one of the diseases studied. Across all diseases, we identified a large number of further signals ( including 58 loci with single-point P values between 10(-5) and 5 X 10(-7)) likely to yield additional susceptibility loci. The importance of appropriately large samples was confirmed by the modest effect sizes observed at most loci identified. This study thus represents a thorough validation of the GWA approach. It has also demonstrated that careful use of a shared control group represents a safe and effective approach to GWA analyses of multiple disease phenotypes; has generated a genome-wide genotype database for future studies of common diseases in the British population; and shown that, provided individuals with non-European ancestry are excluded, the extent of population stratification in the British population is generally modest. Our findings offer new avenues for exploring the pathophysiology of these important disorders. We anticipate that our data, results and software, which will be widely available to other investigators, will provide a powerful resource for human genetics research.

/pdf/genome-wide-association-study-of-14-000-cases-of-seven-5ay7q0q3vy.pdf

Genome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls

Meta-analysis of effect of high vs low vitamin E intake on cardiovascular mortality for observational and intervention studies (letter)

Background: Accelerated early growth promotes atherosclerosis in experimental models and is associated with increased vascular risk in adults. However the underlying mechanisms and their time course are poorly understood. We have assessed the impact of early postnatal growth rate on blood pressure and BMI in childhood. Methods: We studied 4652 children aged 10 years nested within the Avon Longitudinal Study of Parents and Children (ALSPAC). Blood pressure was measured and BMI was calculated as weight (kg)/ height (m) 2 . Lipid profile was assessed in all children at the age of 7years. Weight and length were recorded at birth and within a period of 2 months. All values were converted to z scores. Change in growth in the first two months was assessed as the change in weight and length z score between birth and the first two months of life. Results : Faster weight gain in the first two months was associated with increased systolic blood pressure (SBP) at 10 years later (0.5 [0.2, 0.9]; B [95%CI]; p 2 respectively; p Conclusion: We have demonstrated that more rapid weight gain during the first two months of life is associated with increased SBP and BMI as early as 10 years of age in a healthy, prospectively followed, contemporary cohort. Further studies are needed to assess the implications of these abnormalities for cardiovascular risk in adulthood.

Abstract 3989: Accelerated Early Postnatal Growth is Associated with Increased Blood Pressure and Body Mass Index in Childhood

Dual Energy X-Ray Absorptiometry (DXA) Estimation of Childrenʼs Abdominal Adiposity Measured By Magnetic Resonance Imaging (MRI).

EDITOR—The British ministry of defence announced recently that a new group of British troops are to be offered anthrax vaccination in preparation for service in the Gulf.1 The secretary of state for defence was vaccinated on camera as part of an effort to convince service personnel and the public that this vaccination is safe.

It would have been far more impressive if …

All troops sent to Gulf should be randomised to receive anthrax vaccination or placebo

Background & Aims: Retinoids may have a role in the chemoprevention of potentially malignant disorders of the upper aerodigestive tract. Therefore, we conducted a systematic review of randomised controlled trials to examine the effect of synthetic retinoid interventions in people with cancer or potentially malignant disorders of the upper digestive tract. Methods: We searched five electronic databases and reference lists to locate all eligible trials and analysed trial quality. Outcome measures were all-cause and cancer mortality, disease-free survival, second primary cancer, cancer and potentially malignant disorder recurrence and progression to cancer. Results of individual trials were combined by use of random-effects meta-analyses. Results & Conclusions: We identified 17 15 trials, eightnine in people with upper aerodigestive tract cancer and seven eight in people with potentially malignant disorders, respectively. The results provide little evidence that retinoids have a beneficial effect on disease-free survival (OR=0.74, 95% CI =0.51, 1.09), all cause mortality (OR = 1.28, 95% confidence interval [CI] =1.00 to 1.65), disease-free survival (OR=0.74, 95% CI =0.51, 1.09), recurrence of cancer (OR = 1.47, 95% CI = 0.95, 2.26), development of second primary cancers (OR = 0.96, 95% CI = 0.76, 1.20) or the progression to malignancy (OR = 0.69, 95% CIs = 0.22, 2.15). There was even a suggestion of harm for some outcomes. There was also a suggestion that retinoids may decrease the recurrence of potentially malignant disorders (OR = 0.22, 95% CIs = 0.03, 1.34). For now there is no evidence to support the use of retinoids in people with upper aerodigestive tract cancer.

Synthetic Retinoid Interventions and Outcomes in People with Cancer or Potentially Malignant Disorders of the Upper Aerodigestive Tract: A Systematic Review and Meta-analysis

Andy R Ness

Papers

Meta-analysis of effect of high vs low vitamin E intake on cardiovascular mortality for observational and intervention studies (letter)

Abstract 3989: Accelerated Early Postnatal Growth is Associated with Increased Blood Pressure and Body Mass Index in Childhood

Dual Energy X-Ray Absorptiometry (DXA) Estimation of Childrenʼs Abdominal Adiposity Measured By Magnetic Resonance Imaging (MRI).

All troops sent to Gulf should be randomised to receive anthrax vaccination or placebo

Synthetic Retinoid Interventions and Outcomes in People with Cancer or Potentially Malignant Disorders of the Upper Aerodigestive Tract: A Systematic Review and Meta-analysis