Meta-analysis in the context of "Hierarchy of evidence"

Scientific consensus is the majority judgment and position by active, qualified experts in a specific scientific discipline to establish a conclusion or fact. Scientific consensus results from the self-correcting scientific process of peer review, replication of the event through the scientific method, scholarly debate, meta-analysis, and publication of high-quality review articles, monographs, or guidelines in reputable books and journals to establish facts and durable knowledge about the topic.

Reaching consensus requires significant scientific agreement among qualified experts, a process based on scientific substantiation of a claim that meets the burden of proof by proposing a possible cause-and-effect mechanism supported by the totality of evidence, leading to agreement among experts. In many countries, scientific consensus established on significant scientific agreement is the basis for regulatory approval of drugs to specify a health claim for the properties of the approved therapeutic agent.

Bariatric surgery (also known as metabolic surgery or weight loss surgery) is a surgical procedure used to manage obesity and obesity-related conditions. Long term weight loss with bariatric surgery may be achieved through alteration of gut hormones, physical reduction of stomach size (stomach reduction surgery), reduction of nutrient absorption, or a combination of these. Standard of care procedures include Roux en-Y bypass, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch, from which weight loss is largely achieved by altering gut hormone levels responsible for hunger and satiety, leading to a new hormonal weight set point.

In morbidly obese people, bariatric surgery is the most effective treatment for weight loss and reducing complications. A 2021 meta-analysis found that bariatric surgery was associated with reduction in all-cause mortality among obese adults with or without type 2 diabetes. This meta-analysis also found that median life-expectancy was 9.3 years longer for obese adults with diabetes who received bariatric surgery as compared to routine (non-surgical) care, whereas the life expectancy gain was 5.1 years longer for obese adults without diabetes. The risk of death in the period following surgery is less than 1 in 1,000. Bariatric surgery may also lower disease risk, including improvement in cardiovascular disease risk factors, fatty liver disease, and diabetes management.

The causes of food going uneaten are numerous and occur throughout the food system, during production, processing, distribution, retail and food service sales, and consumption. Overall, about one-third of the world's food is thrown away. A similar amount is lost on top of that by feeding human-edible food to farm animals (the net effect wastes an estimated 1144 kcal/person/day). A 2021 meta-analysis, that did not include food lost during production, by the United Nations Environment Programme found that food waste was a challenge in all countries at all levels of economic development. The analysis estimated that global food waste was 931 million tonnes of food waste (about 121 kg per capita) across three sectors: 61 percent from households, 26 percent from food service and 13 percent from retail.

Wasted food is a major part of the impact of agriculture on climate change (it amounts to 3.3 billion tons of carbon dioxide equivalent emissions annually) and other environmental issues, such as land use, water use and loss of biodiversity. Prevention of food waste is the highest priority, and when prevention is not possible, the food waste hierarchy ranks the food waste treatment options from preferred to least preferred based on their negative environmental impacts. Reuse pathways of surplus food intended for human consumption, such as food donation, is the next best strategy after prevention, followed by animal feed, recycling of nutrients and energy followed by the least preferred option, landfill, which is a major source of the greenhouse gas methane. Other considerations include unreclaimed phosphorus in food waste leading to further phosphate mining. Moreover, reducing food waste in all parts of the food system is an important part of reducing the environmental impact of agriculture, by reducing the total amount of water, land, and other resources used.

Food loss and waste is food that is discarded or otherwise lost uneaten. This occurs throughout the food system, during production, processing, distribution, retail and food service sales, and consumption. Overall, about one-third of the world's food is thrown away, and a similar proportion of calories is lost on top of that by feeding human-edible food to farm animals. A 2021 meta-analysis by the United Nations Environment Programme estimated that global food waste amounted to 931 million tonnes annually (about 121 kg per person) across three sectors: 61 percent from households, 26 percent from food service and 13 percent from retail.

Food waste is addressed through prevention (e.g. by food preservation), reuse (e.g. food donation), animal feed, or recycling. Discarding food in landfills is to be avoided because it is a major source of the greenhouse gas methane. Reducing food waste in all parts of the food system is an important part of reducing the environmental impact of agriculture, by reducing the total amount of water, land, and other resources used.

A pituitary adenoma is a tumor that occurs in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas. Pituitary adenomas represent from 10% to 25% of all intracranial neoplasms, with an estimated prevalence rate in the general population of approximately 17%.

Non-invasive and non-secreting pituitary adenomas are considered to be benign in the literal as well as the clinical sense, though a 2011 meta-analysis of available research showed that research to either support or refute this assumption was scant and of questionable quality.

The Cochrane Library (named after Archie Cochrane) is a collection of databases in medicine and other healthcare specialties provided by Cochrane and other organizations. At its core is the collection of Cochrane Reviews, a database of systematic reviews and meta-analyses that summarize and interpret the results of medical research. The Cochrane Library aims to make the results of well-conducted clinical trials readily available and is a key resource in evidence-based medicine.

A psychiatric or psychotropic medication is a psychoactive drug taken to exert an effect on the chemical makeup of the brain and nervous system. Thus, these medications are used to treat mental illnesses. These medications are typically made of synthetic chemical compounds and are usually prescribed in psychiatric settings, potentially involuntarily during commitment. Since the mid-20th century, such medications have been leading treatments for a broad range of mental disorders and have decreased the need for long-term hospitalization, thereby lowering the cost of mental health care. The recidivism or rehospitalization of the mentally ill is at a high rate in many countries, and the reasons for the relapses are under research.

A 2022 umbrella review of over 100 meta-analyses found that both psychotherapies and pharmacotherapies for adult mental disorders generally yield small effect sizes, suggesting current treatment research may have reached a ceiling and needs a paradigm shift.