Obesity and estrogen as risk factors for gastroesophageal reflux symptoms.

CONTEXT Gastroesophageal reflux and obesity are both increasing in prevalence. The scientific evidence for an association between these conditions is sparse and contradictory. A difference between sexes concerning this relation has been proposed. OBJECTIVE To evaluate the relation between body mass and gastroesophageal reflux symptoms and determine how this relation is influenced by female sex hormones. DESIGN Population-based, cross-sectional, case-control study. SETTING Two consecutive public health surveys within the county of Nord-Trondelag, Norway, conducted in 1984-1986 and 1995-1997. PARTICIPANTS Among 65 363 adult participants in the second survey, 3113 individuals who reported severe heartburn or regurgitation during the last 12 months were defined as cases, whereas 39 872 persons without reflux symptoms were defined as controls. MAIN OUTCOME MEASURE Risk of reflux, estimated using multivariate logistic regression, with odds ratios (ORs) and 95% confidence intervals (CIs) as measures of association. RESULTS There was a dose-response association between increasing body mass index (BMI) and reflux symptoms in both sexes (P for trend <.001), with a significantly stronger association in women (P<.001). Compared with those with a BMI less than 25, the risk of reflux was increased significantly among severely obese (BMI >35) men(OR, 3.3; 95% CI, 2.4-4.7) and women (OR, 6.3; 95% CI, 4.9-8.0). The association between BMI and reflux symptoms was stronger among premenopausal women compared with postmenopausal women (P<.001), although use of postmenopausal hormone therapy increased the strength of the association (P<.001). Reduction in BMI was associated with decreased risk of reflux symptoms. CONCLUSIONS There is a significant association between body mass and symptoms of gastroesophageal reflux. The association is stronger among women, especially premenopausally, and use of hormone therapy strengthens the association, suggesting that estrogens may play an important role in the etiology of reflux disease.