Lifestyle Factors Associated With Reflux Symptoms Without Erosive Esophagitis in Japanese Individuals With and Without Obesity Undergoing Health Checkups: A Cross-Sectional Study.

Background: Non-erosive reflux disease (NERD) is the most prevalent gastroesophageal reflux disease phenotype. However, lifestyle factors associated with reflux symptoms in the absence of erosive esophagitis, a presentation often classified as NERD in epidemiological studies, remain underexplored in Japan. This study aimed to investigate lifestyle factors associated with reflux symptoms without erosive esophagitis, stratified by obesity status. Methods: We conducted a cross-sectional study of 2116 Japanese adults undergoing annual health checkups, including upper endoscopy and lifestyle questionnaires. Multivariable logistic regression was used to identify factors associated with reflux symptoms without erosive esophagitis, stratified by BMI-defined obesity and abdominal obesity. Results: Reflux symptoms without erosive esophagitis were present in 18.6% of participants. In multivariable analysis, past smoking, current smoking, weight gain ≥ 10 kg since age 20 years, poor sleep, and hiatal hernia were independently associated with reflux symptoms without erosive esophagitis, whereas neither BMI-defined obesity nor abdominal obesity showed independent associations. In obesity-stratified analyses, smoking, weight gain, fast eating, poor sleep, and hiatal hernia were independently associated with reflux symptoms without erosive esophagitis among nonobese participants. However, formal interaction testing showed no significant effect modification by obesity status. Conclusions: Smoking, long-term weight gain, fast eating, poor sleep, and hiatal hernia are key factors associated with reflux symptoms without erosive esophagitis. These findings may help identify potentially modifiable factors associated with reflux symptoms without erosive esophagitis in primary care settings.