The symptoms of celiac disease are diverse, and the disease is often asymptomatic. Without active serologic screening, most cases probably remain undiagnosed. Recent serologic screening assays allow mass screening for the disease. However, there is no evidence as yet to suggest that symptom-free celiac disease patients run an increased risk of small intestinal lymphoma or other complications. The prevention of osteoporosis seems to be the strongest indicator for widespread screening today. Screening asymptomatic individuals for celiac disease may be even harmful. A lifelong gluten-free diet is not easy to maintain, and the subject's quality of life may deteriorate. It is also debatable whether patients found by active screening adhere to a gluten-free diet similarly to symptomatic ones. The cost-effectiveness of population screening is dubious. Serologic screening should be applied in individuals with even subtle symptoms indicative of celiac disease, such as subclinical-isolated iron deficiency. In various autoimmune conditions, the risk of celiac disease is approximately 5% and, in individuals with affected first-degree relatives, 15%. Infertility, neurologic symptoms such as polyneuropathy, ataxia, epilepsy with posterior cerebral calcification, and osteoporosis are conditions in which celiac disease should be kept in mind. Elevated aminotransferases and liver failure can lead to a diagnosis of celiac disease. Evidence today does not support mass screening of celiac disease. Instead, increased alertness should be observed in patients at risk of the condition.

NIH consensus and state-of-the-science statements are prepared by independent panels of health professionals and public representatives on the basis of (1) the results of a systematic literature review prepared under contract with the Agency for Healthcare Research and Quality (AHRQ); (2) presentations by investigators working in areas relevant to the conference questions during a 2-day public session; (3) questions and statements from conference attendees during open discussion periods that are part of the public session; and (4) closed deliberations by the panel during the remainder of the second day and morning of the third. This statement is an independent report of the panel and is not a policy statement of the NIH or the Federal Government. The statement reflects the panel's assessment of medical knowledge available at the time the statement was written. Thus, it provides a "snapshot in time" of the state of knowledge on the conference topic. When reading the statement, keep in mind that new knowledge is inevitably accumulating through medical research.

Adverse reactions to food that result in gastrointestinal symptoms are common in the general population; while only a minority of such individuals will have symptoms due to immunologic reactions to foods, gastrointestinal food allergies do exist in both children and adults. These immune reactions are mediated by immunoglobulin E-dependent and -independent mechanisms involving mast cells, eosinophils, and other immune cells, but the complexity of the underlying mechanisms of pathogenesis have yet to be fully defined. Knowledge of the spectrum of adverse reactions to foods that affect the digestive system, including gastrointestinal food allergy, is essential to correctly diagnose and manage the subset of patients with immunologically mediated adverse reactions to foods. Potentially fatal reactions to food necessitate careful instruction and monitoring on the part of health care workers involved in the care of individuals at risk of anaphylaxis. New methods of diagnosis and novel strategies for treatment, including immunologic modulation and the development of hypoallergenic foods, are exciting developments in the field of food allergy.

Heartburn is a symptom complex that has traditionally been accepted as an acid-mediated event and a reliable indicator of gastroesophageal reflux disease. Recently, however, these concepts have been questioned because patients with endoscopy-negative "heartburn" have lower response rates to acid suppression with proton pump inhibitors than do patients with endoscopy-positive "heartburn," ie, erosive esophagitis. As explanation for this, 3 different mechanisms have been proposed to explain the occurrence of heartburn in the endoscopy-negative setting. They are: esophageal visceral hypersensitivity, sustained esophageal contractions, and abnormal tissue resistance. In this report, we review the observations in support of each concept and propose a means for reconciling them under one hypothesis: abnormal tissue resistance. Essential to this review and to the conclusions drawn about the pathogenesis of heartburn in nonerosive reflux disease is a reaffirmation of the definition of reflux-associated "heartburn" as an acid-mediated event requiring "relief by antacids" as a necessary component of the history.