The prevalence of some gastrointestinal (GI) disorders varies with race and ethnicity. For example, dyspepsia and irritable bowel syndrome are reported less frequently by African Americans. Phenotypes, symptoms, quality of life, health care use, and outcomes of inflammatory bowel diseases vary among racial and ethnic groups.
Gastroparesis, or delayed gastric emptying, means that the stomach has trouble clearing its contents. In most cases, gastroparesis is a chronic condition in which food moves slowly or stops moving in the stomach, due to problems with stomach wall muscles or neurologic alterations. Symptoms include nausea, vomiting, early satiety, postprandial fullness, and abdominal pain. Treatments can include gastric electrical stimulation. Gastroparesis greatly affects patients’ quality of life and can be caused by diabetes (see figure), although many cases have unknown causes.
The prevalence of gastroparesis has been estimated to be 4% of the population. Most patients with gastroparesis (up to 80%) are women. Metoclopramide reduces symptoms of gastroparesis in women, but not in men, with diabetes.
Few studies have assessed the characteristics, symptom severity, or effects on quality of life of gastroparesis in minority populations.
Henry P. Parkman et al assessed variations in the etiology of gastroparesis, the type and severity of gastroparetic symptoms, quality of life, among patients of different races/ethnicities and sexes. They collected data from the The National Institutes of Health Gastroparesis Consortium’s Gastroparesis Registry and Gastroparesis Registry 2 on 718 patients with gastroparesis: 552 (77%) reported non-Hispanic white, 83 (12%) reported Hispanic ethnicity, 62 (9%) reported non-Hispanic black race, and 21 (3%) reported non-Hispanic other racial groups (Asian, Native American, Pacific Islander, or multiracial).
Parkman et al found that Hispanic and black individuals were more likely to have diabetic etiology for gastroparesis than white persons, who more often had idiopathic gastroparesis. Black patients had higher severity of nausea or vomiting and were more likely to require hospitalization than Hispanic or white patients.
Women were more likely to have idiopathic gastroparesis, with more severe bloating and postprandial fullness, then men. However, women had greater levels of symptom improvement over time than men, with greater reductions in nausea, stomach size, and upper abdominal pain.
In the analysis of data from the first registry of the Gastroparesis Research Consortium, only 28% of the 262 patients had reductions in gastroparesis symptom scores of 1 or more at 48 weeks. This study found similar reductions in gastroparesis symptom scores among the ethnic/racial groups after 48 weeks. However, vomiting decreased more in non-Hispanic black patients compared with non-Hispanic white or Hispanic patients.
Post-menopause women had less severe nausea, retching, and vomiting than premenopause women. Post-menopause women taking hormone-replacement therapy had greater upper abdominal pain and discomfort than women not taking hormone-replacement therapy
The authors conclude that race, ethnicity, and sex associate with presentation and treatments of gastroparesis.
Why do people of different races or sex have different symptoms, severity, and responses to treatment for this gastric disorder? Differences in genetic factors might account for some of the variation. For example, researchers have found variations in the heme oxygenase 1 gene (HMOX1) between black or African American subjects with gastroparesis compared with non-black subjects with gastroparesis. Reduced expression of HMOX1 and/or loss of HMOX1-containing macrophages leads to loss of pacemaker cells (interstitial cells of Cajal) in the stomach.
Parkman et al also explain that socioeconomic factors and health care access to specific therapies might account for differences in symptoms and treatment. For this study, the authors did not have information on types of medical insurance the patients had, which can influence treatments received. Racial differences have also been observed in treatment of inflammatory bowel diseases and GI cancers.
Mechanisms have been proposed for the sex differences in GI disorders, including slower transit time in women, the effects of menstrual cycle, hormones, and nitric oxide.
August is Gastroparesis Awareness Month.