Body mass and reflux oesophagitis: an oestrogen-dependent association?

There is widespread belief that obesity is associated with gastro-oesophageal reflux disease, but the scientific evidence is weak and contradictory. Our aim is to evaluate the relation between body mass and reflux oesophagitis.

A population-based case-control study of endoscopically verified case subjects with reflux oesophagitis, and of randomly selected, control subjects matched for age, sex and area of residence. Subjects were classified within three body mass index (BMI) categories: BMI <25 (normal in the WHO classification), BMI 25-30 (overweight) and BMI >30 (obese). Odds ratios (OR) with 95% confidence intervals (CI) were the measures of association.

Of 179 matched case-control pairs included in the study, 71 pairs were female. In males, no association between overweight and/or obesity and the risk of reflux oesophagitis was found. In females, there was a strong association between increasing BMI and the risk of reflux oesophagitis, with an OR of 2.9 (95% CI: 1.1-7.6) in the BMI 25-30 group and 14.6 (95% CI: 2.6-80.9) in the BMI >30 group (P value for trend = 0.0007). The association between obesity and oesophagitis was further strengthened by the use of oestrogen replacement medication.

The study discloses a strong and dose-dependent association between body mass and reflux oesophagitis in women as opposed to no association among men. This association might be caused by increased oestrogen activity in overweight and obese females.