Heartburn is one of the most common gastrointestinal symptoms experienced worldwide. Ten to 20 percent of Americans suffer from acid reflux that causes burning in the chest (heartburn).
http://www.oaoa.com/people/health/medical_matters/article_d9c59244-4880-11e7-bf2b-ab0c64b80505.html
MEDICAL MATTERS: Got GERD? Heartburn and what you can do about it.