Upper Gastrointestinal Symptoms Are More Frequent in Female than Male Young Healthy Japanese Volunteers as Evaluated by Questionnaire

BACKGROUND/AIMS: Upper gastrointestinal symptoms are more frequent and severe in female than in male outpatients in Japan. This study compared the upper gastrointestinal symptoms between healthy male and female young adult volunteers using a questionnaire. METHODS: In total, 581 third-grade medical students at Saga Medical School aged 22 to 30 years underwent upper gastrointestinal endoscopy and completed a questionnaire (frequency scale for symptoms of gastroesophageal reflux disease) from 2007 to 2013. Of these 581 students, 298 who were negative for Helicobacter pylori infection and had no particular lesions on endoscopic examination were enrolled in the present evaluation. A symptom was defined as positive when the subject evaluated the frequency of the symptom as sometimes, often, or always. RESULTS: The subjects comprised of 163 males (average age, 23.7 years) and 135 females (average age, 23.1 years). Upper gastrointestinal symptoms were more frequent in the females (75 of 135, 55.6%) than males (69 of 163, 42.3%; P < 0.05), with a high score for 4 symptoms (bloated stomach, heavy feeling in the stomach after meals, subconscious rubbing of the chest with the hand, and feeling of fullness while eating meals). Of the 144 subjects (69 males and 75 females) who complained of these symptoms, the females complained of dysmotility symptoms more often than did the males, but this was not true for reflux symptoms. CONCLUSIONS: This study suggests that females develop upper gastrointestinal symptoms more frequently than do males among the young healthy Japanese population.

Liquid-containing Refluxes and Acid Refluxes May Be Less Frequent in the Japanese Population Than in Other Populations: Normal Values of 24-hour Esophageal Impedance and pH Monitoring

BACKGROUND/AIMS: Twenty-four-hour esophageal impedance and pH monitoring allows detection of all types of reflux episodes and is considered the best technique for identifying gastroesophageal refluxes. However, normative data for the Japanese population are lacking. This multicenter study aimed to establish the normal range of 24-hour esophageal impedance and pH data both in the distal and the proximal esophagus in Japanese subjects. METHODS: Forty-two healthy volunteers (25 men and 17 women) with a mean ± standard deviation age of 33.3 ± 12.4 years (range: 22–72 years) underwent a combined 24-hour esophageal impedance and pH monitoring. According to the physical and pH properties, distal or proximal esophageal reflux events were categorized. RESULTS: Median 45 reflux events occurred in 24 hours, and the 95th percentile was 85 events. Unlike previous reports, liquid-containing reflux events are median 25/24 hours with the 95th percentile of 62/24 hours. Acidic reflux events were median 11/24 hours with the 95th percentile of 39/24 hours. Non-acidic gas reflux events were median 15/24 hours with the 95th percentile of 39/24 hours. Proximal reflux events accounted for 80% of the total reflux events and were mainly non-acidic gas refluxes. About 19% of liquid and mixed refluxes reached the proximal esophagus. CONCLUSIONS: Unlike previous studies, liquid-containing and acidic reflux events may be less frequent in the Japanese population. Non-acidic gas reflux events may be frequent and a cause of frequent proximal reflux events. This study provides important normative data for 24-hour impedance and pH monitoring in both the distal and the proximal esophagus in the Japanese population.