This study indicates that clinicians should pay special attention to food avoidance and negative effects on relationships, daily activities, and social reaction in patients with IBS-D and IBS-M, as these domains drove down the quality of life . Patients may also experience migration between predominant symptoms and IBS subtypes over time. The reported prevalence of IBS is likely to be higher in communities with higher perceived stress, lower perceived quality of life, greater potential gain from receiving a diagnosis, or fewer barriers to health care access [4, 16, 17]. These criteria incorporate the many scientific and clinical advances made since the release of the previous version Rome III in This was part of a larger project to overhaul and update scientific knowledge advances and clinical guidance to optimize the diagnosis and treatment of functional gastrointestinal GI disorders . In addition, "symptom shifting" occurs in some patients, characterized by resolution of functional bowel symptoms followed by development of extra-intestinal functional symptoms . A possible confounding factor in natural history studies of IBS is the effect of treatment, which can result in difficulty discerning symptom variation due to medical intervention versus true natural history [5, 42]. The absence of a criterion-standard case definition or standardized diagnostic criteria over time has created difficulty in defining IBS cases for epidemiologic studies. Many physical symptoms affect the overall well-being of patients with IBS including psychologic health and should not be overlooked or marginalized . This creates a discrepancy between the incidence of symptom onset in the community and first IBS diagnosis physician visit and renders estimates of IBS incidence difficult . Functional GI disorders are idiopathic disorders of gut-brain interaction and, unlike organic and motility disorders, diagnosis involves identification of symptom clusters. IBS significantly diminishes emotional, physical, and occupational functioning and health-related quality of life. However, some prevalence estimates are available. Mortality Although patients with IBS have a significantly reduced quality of life, greater risk of depression and suicidal ideation, and higher frequency of invasive procedures and surgery, community-based studies have not associated IBS with increased mortality risk [4, 46]. This group of conditions have been termed "central sensitivity syndromes.