Ethnic Variation in Lower Esophageal Sphincter Pressure and Length

Abstract

Purpose: Esophageal manometry (EM) is the gold standard examination for diagnosis of esophageal motor disorders. Normal values for EM in ethnic groups residing in the United States are only available for Hispanic Americans in the literature. The aim of this study was to obtain values of EM in healthy adult African American (AA) volunteers and compare these to those obtained in healthy non-Hispanic white (nHw) volunteers to determine if ethnic variation exists in normal esophageal motor function. Methods: Healthy AA and nHw were recruited from the Jacksonville metropolitan area. Ethnicity was self-reported. Exclusion criteria were symptoms suggestive of esophageal disease, medication use or concurrent illness that could affect EM. All underwent EM using a solid-state system with wet swallows (Polygram Net, Medtronic Inc., Minneapolis, MN). Resting lower esophageal sphincter pressure and lower esophageal sphincter length were measured at end-expiration while percent peristaltic contractions, distal esophageal contraction velocity, amplitude and duration were measured after 5 cc H20 swallows. Results: Fifty-six AA and 48 nHw were enrolled. All subjects completed EM without difficulty. Volunteer age ranged from 18 to 57 years old and was not different between groups. Males comprised 48% of both groups. Resting lower esophageal sphincter pressure, lower esophageal sphincter length and distal esophageal contraction duration were significantly higher in AA than nHw (P < 0.05, table). There were no differences seen in percent peristaltic contractions, distal esophageal contraction amplitude, and distal esophageal contraction velocity. Conclusion: Significant ethnic differences exist in EM findings. These differences underscore the need for race specific reference values for EM studies to allow for the accurate diagnosis of esophageal motility disorders in AA patients.Table: Esophageal manometry parameters in healthy African Americans (N = 56) and non-Hispanic whites (N = 48)