Objective: Evaluate the associations between abdominal obesity and gastroesophageal reflux disease (GERD), and their interactions with ethnicity and gender.
Design: A cross-sectional study within an existing cohort. Members completed detailed symptom questionnaires and underwent a standardized examination, including anthropometric measurements.
Setting: A large integrated care health system.
Patients: 111,399 members of the Kaiser Permanente multiphasic health check-up cohort.
Main Outcome Measures: Reflux symptoms.
Results: Recent GERD symptoms were present in 11% of the population. The multivariate odds ratio for GERD with an abdominal diameter (adjusted for BMI) of 30-35 vs. 15-17.9 centimeters was 1.76 (95% confidence interval [CI]1.40-2.21) for whites, 0.89 (95% CI 0.56-1.42) for blacks, and 2.42 (95% CI 0.24 – 24.65) for Asians. The mean abdominal diameter was greater in men (22.1 centimeters, 95% CI 22.0, 22.1) than in women (20.2 centimeters, 95% CI 20.2 – 20.3; p<0.01), but the risk of GERD for any given diameter did not differ by gender. The association between BMI and GERD symptoms was largely mediated through abdominal diameter in whites, but not in blacks and Asians. If causal, the combination of BMI and abdominal diameter explained up to 59% of GERD symptoms in the population.
Conclusions: There was a consistent association between abdominal diameter (independent of BMI) and GERD in whites, but no consistent association in blacks or Asians. The BMI-GERD association was largely mediated through abdominal diameter, particularly in whites. These findings, combined with the increased prevalence of abdominal obesity in males, suggest that increased obesity may disproportionately increase GERD in whites and in males.