Systematic assessment of environmental factors for gastroesophageal reflux disease: An umbrella review of systematic reviews and meta-analyses

Background: Side effects of long-term acid suppression have increased the scholars' interest in nonpharmacologic intervention. Aims: We summarized an umbrella review of the association between environmental factors and gastroesophageal reflux disease (GERD) and assessed their credibility. Methods: We appraised systematic reviews and meta-analyses. For each meta-analysis, we considered the effect size, 95% confidence interval, the heterogeneity, small-study effects, P-value for excess significance and largest study significant, then we graded the evidence according to Assessment of Multiple Systematic Reviews and the GRADE assessment. Results: 23 publications met the inclusion criteria (13 meta-analyses and 10 systematic reviews), which evaluated 24 environmental factors. Among observational studies, we identified 7 risk factors: overweight/obesity [GERD/erosive esophagitis (EE)/GERD symptom], central adiposity [EE], smoking [GERD], alcohol [GERD/EE/non-erosive reflux disease (NERD)], NSAID [GERD], coffee [EE], Helicobacter pylori eradication [EE], and 1 protective factor: physical activity [GERD], this was based on a suggestive evidence of credibility. Across intervention studies, we identified 1 risk factor-Helicobacter pylori eradication [GERD] and 1 protective factor-breathing exercises [GERD], evidence for both was low grade. Conclusions: We found varying levels of evidence for different environmental factors of GERD. None of them was proven to be convincing or highly recommended. (c) 2020 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.