Medical News

Digestive Health Research

While progress is being made in our understanding of the gastrointestinal disorders, important questions remain. For example:

• What causes the disorders?
• Why do certain people get them?
• How do we best treat the conditions?
• How do we prevent the disorders?
• How do we cure them?

Sound medical research is needed to explore these questions. Here we report a sampling of research studies that provide clues to better understanding GI disorders. Each new study adds a small piece to the puzzle, making the big picture clearer.

To learn more about medical research, visit our web site at www.giResearch.org.

A sampling of recently published studies

 

Barrett's Esophagus Risk Factors

Elucidating Risk Factors for Barrett's Esophagus

Scientists report that extra abdominal fat may be a risk factor for Barrett’s esophagus. Barrett’s esophagus is a precancerous condition where the cells lining the esophagus change in shape and organization. Short of surgical removal of the esophagus, there is no effective cure for the condition. Known risk factors for Barrett’s esophagus include being male, Caucasian, or over the age of 40. Individuals with gastroesophageal reflux disease (GERD), in which stomach acid flows backward into the esophagus, also are at increased risk of developing Barrett’s esophagus. In turn, the condition puts patients at greater risk of developing esophageal adenocarcinoma, which is rapidly increasing in the United States. Therefore, research to further understanding of the risk factors for Barrett’s esophagus may yield information that also would provide insight into the development of esophageal adenocarcinoma.

Scientists recently examined the association between obesity and abdominal girth and the occurrence of Barrett’s esophagus and GERD. Obesity is thought to be a risk factor for GERD, and extra abdominal fat could directly promote acid reflux by placing added pressure on the stomach. Obesity was determined using body mass index (BMI), a measure that takes both height and weight into account, and abdominal girth was measured simply as waist size. In this study, while there was no association of BMI with Barrett’s esophagus, larger abdominal circumference was moderately associated with the condition. The association was strongest in individuals with no GERD symptoms. When GERD symptoms were included in the analysis, the association between abdominal girth and Barrett’s esophagus was decreased, which was expected as GERD symptoms may partly mediate the effect of abdominal girth in the development of Barrett’s esophagus. These data suggest that larger abdominal girth may be a risk factor for both GERD and Barrett’s esophagus. Although the mechanism by which extra abdominal fat raises the risk of these conditions is unknown, it could act by increasing pressure on the stomach and contributing to GERD symptoms through effects on gastrointestinal mobility. The results of this research suggest that larger abdominal circumference, but not overall obesity, is a risk factor for Barrett’s esophagus. Based on these findings, reduction of waist size may be advisable for patients at high risk of developing this condition or subsequent esophageal carcinoma.

_{– Corley DA, Kubo A, Levin T, Block G, Habel L, Zhao W, Leighton P, Quesenberry C, Rumore GJ, and Buffler PA: Abdominal obesity and body mass index as risk factors for Barrett’s esophagus. Gastroenterology 133: 34-41, 2007.}

_{Source: NIDDK Recent Advances & Emerging Opportunities: Digestive Diseases and Nutrition, January 2008.}

The Narcotic Bowel Syndrome

Narcotics are drugs, usually opiates such as morphine or oxycodone, which can relieve pain. In the U.S. narcotics are commonly prescribed for treating patients with pain, usually injuries, sudden painful conditions, or cancer. However, persons with chronic functional GI disorders should not be treated with narcotics, though this may at times be done. We are learning that under some circumstances, the use of narcotics can actually cause pain. Over time, narcotics can make nerves more sensitive, and make pain worse; they also can slow the bowel, and lead to symptoms of constipation, bloating, or nausea. This relates to the well known effects of narcotics on the bowel, opiate bowel dysfunction.

In a review article by a group from the University of North Carolina, a subset of opiate bowel dysfunction called narcotic bowel syndrome (NBS) is described. This under-recognized syndrome may be becoming more prevalent because of increasing use of narcotics for chronic painful disorders as well as lack of awareness that increased sensation to pain may be caused by long-term narcotic use. The syndrome is characterized by chronic or periodic abdominal pain that gets worse when the effect of the narcotic drug wears down. In addition to pain, which is the primary feature, other symptoms may include nausea, bloating, periodic vomiting, abdominal distension, and constipation. 

The UNC group has developed the following diagnostic criteria for narcotic bowel syndrome:

Chronic or frequently recurring abdominal pain that is treated with acute high-dose or chronic narcotics and all of the following:

• The pain worsens or incompletely resolves with continued or escalating dosages of narcotics;
• There is marked worsening of pain when the narcotic dose wanes and improvement when narcotics are re-instituted (soar and crash);
• There is a progression of the frequency, duration, and intensity of pain episodes;
• The nature and intensity of the pain is not explained by a current or previous GI diagnosis.

The key to diagnosis is the recognition that long-term or increasing dosages of narcotics lead to continued or worsening symptoms rather than benefit.

The UNC group has also developed a treatment approach. The narcotic is withdrawn and substituted with effective alternative medications to help manage the pain and the bowel symptoms until the narcotics are removed from the system. This requires the doctor and patient working closely together. The doctor must take time to explain the condition, the reasons for withdrawing the narcotics, and the alternative treatment plan. The treatment process may take several weeks or months to implement satisfactorily, with the doctor staying in touch with the patient during this period.

_{Source: Grunkemeier DMS, Cassara JE, Dalton CB, Drossman DA. The narcotic bowel syndrome: clinical features, pathophysiology, and management. Clin Gastroenterol Hepatol 2007;5:1126-1139.}

Updated guidelines for treating constipation in children

Constipation is a common pediatric problem. To assist health care professionals who care for children with constipation, the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) previously published a clinical guideline based on an integration of medical evidence with expert opinion. To evaluate studies published since then, the NASPGHAN Constipation Guideline Committee performed a comprehensive and systematic review of the medical literature since 1997, to identify, review and rate the quality of new evidence. Based on this review, the recommendations of the original clinical guideline were reaffirmed with several modified according to the new evidence. Among the updates reported: 

1. There are conflicting reports on the value of fiber for constipated children. Some studies find that constipated children are consuming less fiber than unaffected children; other studies find constipated children are consuming more fiber; and still others find no difference. The society recommends that further studies are needed before it can make a recommendation one way or the other.
2. Polyethylene glycol 3350 (PEG 3350) is an osmotic laxative which has been found to help disimpaction in constipated children. However, before it can recommend this laxative for use in babies the society recommends further safety studies.
3. The society has reviewed studies looking at biofeedback to help improve symptoms of constipation in children. No study showed long-term improvement; however, short-term improvements (about three months in length) were seen. The society recommends that biofeedback therapy can be an effective short-term treatment in some patients.
4. Studies looking at the effect of cow’s milk in the diet show mixed results. The society recommends that in children whose constipation does not improve on standard medical and behavioral management, it is worth considering a short trial of a cow’s milk-free diet to see if symptoms improve.  

Does allergy play a role in irritable bowel syndrome (IBS) and in constipation? 

There is a common belief that allergy contributes to constipation or irritable bowel syndrome (IBS) with symptoms of constipation. However, reports have not been able to conclusively show that restricting allergens from a diet improves IBS or constipation symptoms. This study from Italy of children aged 3–13 years tried to find an answer looking in the other direction, by looking at whether children with demonstrated allergies – such as asthma, eczema, or food allergy – are more prone to have constipation or IBS. A group 196 children with allergic symptoms were enrolled and compared to a second group 127 nonallergic children as controls. Both groups were tested for allergies to a wide range of common food and other allergens, using a rigorous test called a skin prick test (SPT). Using a symptom questionnaire based on the Rome criteria for functional gastrointestinal disorders, the occurrence of constipation was found to be similar in both groups. IBS was found in 6.6% of the allergic children and in 6.3% of the nonallergic controls.   

The study found that allergic children were not more likely than nonallergic children to have IBS or constipation symptoms. It was found that children who had at least one SPT allergic reaction to a food item were more likely to have IBS than children with no reaction to the food SPTs. The study concludes that children with allergies do not need to fear increased chances of developing IBS, but if they have positive SPT tests to food, they should also be examined for the presence of IBS symptoms.

_{Source: Caffarelli C, Coscia A, Baldi F, Borghi A, Capra L, Cazzato S, Migliozzi L, Pecorari L, Valenti A, Cavagni G. Characterization of irritable bowel syndrome and constipation in children with allergic diseases. Eur J Pediatr. 2007 Mar 8; [Epub ahead of print]}

How common is food allergy in children?

This study from Brazil reviewed current research (2000–2006) on food allergies in children. Their primary conclusion is that food allergies are very often over-diagnosed. Other specific findings include: 

• Diagnoses of allergic diseases, and especially allergies to food, have increased in the last 20 years or so.
• Children are much more likely to be diagnosed as having food allergies than adults.
• Food intolerance is often mistaken for food allergy. Food intolerance occurs when the body cannot adequately digest a portion of a particular food. Food allergy is an immune system response where the body creates antibodies as a reaction to certain food.  
• Patients and their families are known to overestimate their own food allergies. In one study of 500 newborn babies, 28% of them were thought to have food allergies by their parents. However, a rigorous test for food allergies found that only 6% had a reaction to the suspect food. 
• Elimination diets (a doctor-supervised diet in which a specific food or ingredients is removed from the diet to test whether symptoms disappear in the absence of the suspect food item) is not always a reliable test for true food allergy. The recommended diagnostic procedure is skin testing followed by IgE antibody testing.
• Currently, the only strategy for managing a food allergy is a diet with total elimination of the offending food item. To prevent malnutrition or other ill effects, these diets must be supervised by a physician.
• Most parents are unable to identify common allergic food ingredients on product labels, so any restrictive diet should be accompanied by extensive education about dietary management needs.
• Cow’s milk allergy usually goes away within the first three years of life in most patients.

While soy-based formulas have been successfully used to treat babies with demonstrated food allergies or food intolerance, there is no basis for recommending soy formula as a way to prevent food allergies.      

_{Source: Ferreira CT, Seidman E. Food allergy: a practical update from the gastroenterological viewpoint. J Pediatr (Rio J). 2007 Jan-Feb;83(1):7-20.}

 

Do infants with GERD become adults with GERD?

It is commonly accepted that reflux symptoms will usually resolve during the first year or two of life. Data collected over a one-year period in 19 infants assigned to a placebo group as part of a placebo-controlled drug treatment study of 100 infants total was looked at. It was found that symptoms resolved in more than one-half of those in the placebo assigned group. However, the study also found that microscopic inflammation might continue to be present in the esophagus even after symptoms appear to be gone.

This raises a question. Are these individuals at risk for later problems? The results of this study call attention to the need for better understanding about GERD in infancy and childhood including screening and treatment approaches.

_{Source: Orenstein SR, Shalaby TM, Kelsey SF, Frankel E. Natural history of infant reflux esophagitis: symptoms and morphometric histology during one year without pharmacotherapy. Am J Gastroenterol. 2006 Mar;101(3):628-40.}

Do genetic or environmental factors contribute to irritable bowel syndrome (IBS)?

A study looked at 12,700 Norwegian twins born between 1967 and 1979. It found that both genetic and external factors may contribute to IBS. Identical twins share exactly the same genes. Non-identical twins share 50% of the same genes. The identical twins were more likely to develop IBS due to external factors, such as low birth rate, as well as due to the influence of genetic makeup.

_{Source: Bengtson MB, Ronning T, Vatn M, Harris J. IBS in twins: genes and environment. Gut. 2006 Dec;55(12):1694-1946.}

How does the patient-doctor relationship help treat IBS?

In a Mexico City study of 55 patients seeing a doctor in a specialty referral clinic for the first time, 4 factors were looked at in relation to their seeking health care:

• abdominal pain/discomfort
• fear of cancer
• impairment in daily function
• symptom stressfulness

Of these, pain/discomfort and symptom stressfulness were the most important factors that drove the patients to seek care. Feelings of anxiety, depression, and quality of life impairment arising from cancer fear, daily function impairment, and stress from symptoms were present.

Patients want to talk about and to be given information about their disease. A thorough explanation of the disease and reassurance from the doctor decreased the self-perception of impairment in daily function and cancer fear.

_{Source: Schmulson M, Oritz-Garrido O, Hinojosa C, Arcila D. A single session of reassurance can acutely improve the self-perception of impairment in patients with IBS. Journal of Psychosomatic Research 2006;61:461-467.}

Is childhood GERD a risk factor for adult symptoms?

A study in Texas examined the prevalence and risk factors for current gastroesophageal reflux disease (GERD) symptoms in 113 young adults (mean age 18 years) with a history of childhood GERD (mean age at the time of childhood diagnosis was 10 years). Almost half of the young adults with a history of GERD as children reported that they currently suffer from heartburn and reflux symptoms a minimum of once every week with most of these taking medications to control their symptoms.

The study cautions that the prevalence of GERD found in this group is considerably higher than previously found in a group of this age. Nevertheless, they conclude that childhood GERD should be considered a risk factor for adolescent and adult GERD.

_{Source: El-Serag HB, Richardson P, Pilgrim P, Gilger MA. Determinants of gastroesophageal reflux disease in adults with a history of childhood gastroesophageal reflux disease Clin Gastroenterol Hepatol 2007 Jun;5(6):696-701.}

 

Is there a relationship between IBS, dyspepsia, and quality of life in GERD sufferers? 

Numerous studies show patients diagnosed with GERD are more likely than others to also suffer from irritable bowel syndrome (IBS) or functional dyspepsia (pain or discomfort in the upper abdominal area). A recent study in The Netherlands confirmed this and examined health-related quality of life in these individuals. In patients with GERD (confirmed through a 24-hour pH monitoring test that measures reflux), 25% had dyspepsia, 35% had IBS, and 5% had both. Only 35% had neither IBS nor dyspepsia.

Researchers used a questionnaire with 9 subscales to measure health-related quality of life (HRQoL) in the study participants. Patients who had only GERD had lower scores on 1 of the 9 subscales. GERD patients who also had functional dyspepsia had lower scores on 6 subscales. GERD patients with IBS scored lower on 8 subscales. Patients with GERD, IBS, and functional dyspepsia scored lower on 7 subscales.

The study concluded that in patients with proven GERD, functional dyspepsia and IBS are more prevalent than in the general population; and this prevalence is higher among care-seeking GERD patients. Those GERD patients who also have functional dyspepsia and/or IBS have a much lower HRQoL, suggesting that when GERD is properly treated, health related quality of life is affected mainly by coexisting functional disorders and not by GERD itself.

_{Source: De Vries DR, Van Herwaarden MA, Baron A, Smout AJ, Samsom M. Concomitant functional dyspepsia and irritable bowel syndrome decrease health-related quality of life in gastroesophageal reflux disease Scand J Gastroenterol 2007 Aug;42(8):951-6.}