Gastroesophageal reflux disease (GERD), in which acid from the stomach rises into the esophagus causing heartburn, is a very common and uncomfortable problem. A connection between GERD and increased weight has long been suspected.

This recent study in The New England Journal of Medicine makes a fascinating connection between being overweight and having symptoms of GERD in women. The study looked at over ten thousand women in the Nurses’ Health Study, one of the largest studies of American women that followed a large group of women and tracked multiple aspects of their health. The study gave the women a questionnaire to grade the severity and frequency of heartburn and acid regurgitation. They compared the results of the questionnaires to the women’s body mass index (BMI).

The BMI is a way to adjust a person’s weight for her height and allows us a rough guideline by which to decide if a person’s weight is too high. You can calculate your BMI with the CDC’s BMI calculator.

The results of the study were surprisingly strong. Not only was there a strong correlation between BMI and heartburn, the correlation persisted even in the normal BMI ranges. That means that even in women of normal weight, a few pounds of weight gain resulted in a higher risk of heartburn. Women who had recently lost weight were also less likely to have heartburn than women who had gained weight.

This was a purely observational study, so this can only show that weight and heartburn are associated. It can not prove that one causes the other. I would love to see an experiment in which patients with heartburn are randomized to two groups, one which receives antacids, and a second who receives antacids plus diet and exercise aimed at weight loss. If the second group lost more weight and had less heartburn, this would prove that weight is partially responsible for heartburn symptoms.

There are already lots of other good reasons to keep our weights down: lower blood pressure, lower cholesterol, and better control of diabetes. It’s possible that less frequent heartburn should be added to that list.