Uday C. Ghoshal

Epidemiology of irritable bowel syndrome in Asia: Something old, something new, something borrowed

In this review we have unearthed epidemiological data that; support the ‘old’ concept of irritable bowel syndrome (IBS) as a disorder of civilization, build a ‘new’ symptom profile of IBS for Asia, and persuade us against the use of ‘borrowed’ Western diagnostic criteria and illness models by Asian societies. In the 1960s, IBS was described as a disorder of civilization. Early studies from Asia suggested a prevalence of IBS below 5%. Recent studies from Asia suggest a trend for the more affluent city states like Singapore and Tokyo, to have higher prevalence of 8.6% and 9.8%, respectively, while India had the lowest prevalence of 4.2%. Furthermore, there was a trend among the better educated and more affluent strata of society in several urban Chinese populations for a higher prevalence of IBS, as well as a trend for a higher consultation rate. Across Chinese and Indian predominant populations, a majority of patients with IBS criteria report upper abdominal symptoms such as epigastric pain relieved by defecation, bloating and dyspepsia. Bloating and incomplete evacuation appear to be more important determinants of consultation behavior, than psychological factors. The failure of the Rome criteria to recognize the relationship to meals, may have led to a substantial misclassification of IBS as dyspepsia. The relevance of the Western model of psychological disturbance as a determinant of consultation behavior is questionable because of the accessibility and acceptability of medical consultation for gastrointestinal complaints in many Asian communities.

Asian consensus on irritable bowel syndrome.

Background and Aims:  Many of the ideas on irritable bowel syndrome (IBS) are derived from studies conducted in Western societies. Their relevance to Asian societies has not been critically examined. Our objectives were to bring to attention important data from Asian studies, articulate the experience and views of our Asian experts, and provide a relevant guide on this poorly understood condition for doctors and scientists working in Asia.

How to Interpret Hydrogen Breath Tests

Hydrogen breath tests using various substrates like glucose, lactulose, lactose and fructose are being used more and more to diagnose small intestinal bacterial overgrowth (SIBO) and lactose or fructose malabsorption. Though quantitative culture of jejunal aspirate is considered as gold standard for the diagnosis of SIBO, hydrogen breath tests, in spite of their low sensitivity, are popular for their non-invasiveness. Glucose hydrogen breath test is more acceptable for the diagnosis of SIBO as conventionally accepted double-peak criterion on lactulose hydrogen breath test is very insensitive and recently described early-peak criterion is often false positive. Hydrogen breath test is useful to diagnose various types of sugar malabsorption. Technique and interpretation of different hydrogen breath tests are outlined in this review.

Tropical sprue is associated with contamination of small bowel with aerobic bacteria and reversible prolongation of orocecal transit time.

Background:  In tropical sprue (TS), response to antibiotics may suggest a role for bacterial contamination of the small bowel, which is known in diseases with prolonged orocecal transit time (OCTT).

Bugs and irritable bowel syndrome: The good, the bad and the ugly

Recently, there has been strong interest in the therapeutic potential of probiotics for irritable bowel syndrome (IBS). At the same time, there is a rapidly growing body of evidence to support an etiological role for gastrointestinal infection and the associated immune activation in the development of post‐infectious IBS. In a more controversial area, small intestinal bacterial overgrowth has been associated with a subset of patients with IBS; the issue of whether it is appropriate to treat a subset of IBS patients with antibiotics and probiotics is currently a matter for debate. Thus, it appears that the gastrointestinal microbial flora may exert beneficial effects for symptoms of IBS under some circumstances, while in other situations gut microbes could give rise to symptoms of IBS. How do we make sense of the apparently diverse roles that ‘bugs’ may play in IBS? To address this question, we have conducted an in‐depth review, attempting where possible to draw lessons from Asian studies.

Epidemiology of uninvestigated and functional dyspepsia in Asia: facts and fiction.

Dyspepsia is a syndrome consisting of epigastric pain, burning, fullness, discomfort, early satiety, nausea, vomiting and belching. Functional dyspepsia (FD) is diagnosed if upper gastrointestinal endoscopy does not show structural abnormality explaining these symptoms. 8%-30% and 8%-23% of Asian people suffer from of uninvestigated dyspepsia and FD, respectively. Most patients with uninvestigated dyspepsia are found to have FD. Patients with FD are usually young and there is no predilection to any gender. Overlap of FD with other functional bowel diseases such as irritable bowel syndrome and gastroesophageal reflux disease is common in Asia. Cultural difference in reporting of symptoms of dyspepsia is well-known. Moreover, dietary factors, socio-cultural and psychological issues, gastrointestinal infection including that caused by Helicobacter pylori, frequency of organic diseases such as peptic ulcer and gastric cancer responsible for dyspeptic symptoms in the study population may also influence epidemiology of dyspepsia. There is considerable heterogeneity in the above issues among different Asian countries. More studies on epidemiology of FD are needed in Asia.

The Gut Microbiota and Irritable Bowel Syndrome: Friend or Foe?

Progress in the understanding of the pathophysiology of irritable bowel syndrome (IBS), once thought to be a purely psychosomatic disease, has advanced considerably and low-grade inflammation and changes in the gut microbiota now feature as potentially important. The human gut harbours a huge microbial ecosystem, which is equipped to perform a variety of functions such as digestion of food, metabolism of drugs, detoxification of toxic compounds, production of essential vitamins, prevention of attachment of pathogenic bacteria to the gut wall, and maintenance of homeostasis in the gastrointestinal tract. A subset of patients with IBS may have a quantitative increase in bacteria in the small bowel (small intestinal bacterial overgrowth). Qualitative changes in gut microbiota have also been associated with IBS. Targeting the gut microbiota using probiotics and antibiotics has emerged as a potentially effective approach to the treatment of this, hitherto enigmatic, functional bowel disorder. The gut microbiota in health, quantitative and qualitative microbiota changes, and therapeutic manipulations targeting the microbiota in patients with IBS are reviewed in this paper.

Assessment of cost-effectiveness of universal hepatitis B immunization in a low-income country with intermediate endemicity using a Markov model

BACKGROUND/AIMS Most countries with high hepatitis B (HB) virus endemicity and most high-income countries have introduced immunization programmes against this infection. However, several low-income countries with intermediate HB endemicity have not done so. We performed a cost-effectiveness analysis of universal childhood HB immunization in such countries using India as an example, since available data on this aspect are limited. METHODS Marginal cost of every life-year and quality-adjusted life-year (QALY) gained with universal HB vaccination was calculated using a Markov model. Two types of analyses (including and excluding expenditure on treatment of long-term complications of HB infection) were done. Several sensitivity analyses and Monte-Carlo simulation were performed. RESULTS Universal immunization reduced the HB carrier rate by 71%, and increased the number of years and QALY lived by a birth-cohort by 0.173 years (61.072 vs. 60.899 years) and 0.213 years (61.056 vs. 60.843 years), respectively. Marginal costs were US

The Intestinal Microenvironment and Functional Gastrointestinal Disorders

16.27 per life-year gained and US

Asian Consensus Report on Functional Dyspepsia

13.22 per QALY gained, much lower than annual per capita income. One-way sensitivity analysis and Monte-Carlo simulation confirmed the robustness of the conclusions. CONCLUSIONS Universal HB immunization is highly cost-effective in low-income countries with intermediate endemicity rates.