Acid reflux is one of the most common digestive conditions in the world. Roughly 1 in 10 people globally has gastroesophageal reflux disease (GERD), and in the United States the estimate is closer to 1 in 5 adults. By 2021, approximately 827 million people worldwide were living with the condition, up from about 451 million in 1990.
Global and U.S. Prevalence
The global prevalence of GERD in 2017 was roughly 9,300 cases per 100,000 people, which works out to just over 9%. But the numbers vary dramatically by region. The United States, Italy, Greece, New Zealand, and parts of Latin America, North Africa, the Middle East, and Eastern Europe all have rates above 11%. Meanwhile, countries like Japan, South Korea, France, Denmark, Switzerland, and Iceland report rates below 7%.
In the U.S., the American College of Gastroenterology estimates that up to 20% of the population has GERD. That makes it one of the most frequently diagnosed gastrointestinal conditions in the country, and one of the top reasons people visit a gastroenterologist.
Who Gets It Most
Acid reflux does not hit every age group equally. Prevalence peaks at around 25% in adults aged 25 to 35, which surprises many people who assume it’s primarily a condition of older age. Among adults over 65, estimates range from 14% to 20%, though the rate appears higher in older men (about 11%) than older women (about 5%) in community-based studies.
Body weight is one of the strongest predictors. Being overweight raises the risk of GERD by about 51% compared to people at a normal BMI. Obesity raises it by 76%. And for people at the lower end of the obesity range (a BMI of 30 to 35), the risk is roughly 2.7 times higher than for someone at a healthy weight. A large meta-analysis found that for every 10-point increase in BMI, the risk of GERD goes up by 68%.
Acid Reflux During Pregnancy
Pregnancy is one of the most common triggers. In a study of 510 pregnant women, about 26% experienced reflux symptoms during the first trimester. That number climbed to 36% in the second trimester and 51% in the third. The combination of hormonal changes that relax the valve between the stomach and esophagus, plus the growing uterus pressing upward on the stomach, makes reflux increasingly likely as pregnancy progresses.
Nighttime Reflux Is Extremely Common
Among people who experience heartburn at least once a week, 79% report that it also happens at night. A national survey found that 75% of those with nighttime symptoms said reflux disrupted their sleep. Even in the general population, about 25% of participants in one large sleep study had signs of reflux during the night. Lying flat removes the gravitational advantage that keeps stomach acid in place during the day, which is why symptoms often feel worse at bedtime.
Silent Reflux: No Heartburn, Still Reflux
Not everyone with acid reflux feels the classic burning sensation in the chest. A condition called laryngopharyngeal reflux (LPR), often called “silent reflux,” sends stomach acid all the way up to the throat without causing typical heartburn. Symptoms tend to show up as a chronic cough, hoarseness, throat clearing, or a lump-in-the-throat sensation. In one study using specialized monitoring, about 61% of patients diagnosed with LPR had no signs of traditional GERD at all, meaning the acid was reaching the throat but not causing noticeable symptoms lower down. This makes silent reflux easy to miss or misattribute to allergies or a lingering cold.
The Numbers Are Rising
Acid reflux is becoming more common worldwide. Between 1990 and 2021, the total number of GERD cases globally increased by about 83%, from roughly 451 million to 827 million. New cases diagnosed each year rose by 80% over the same period, from 180 million in 1990 to 324 million in 2021. Population growth explains some of this increase, but even after adjusting for age and population size, the rate has crept upward. Rising obesity rates, dietary shifts toward processed and high-fat foods, and increased recognition of the condition all play a role.
How Many People Take Medication for It
Proton pump inhibitors (PPIs), the class of drugs that includes omeprazole and similar medications, are among the most widely prescribed drugs in the U.S. The proportion of Americans filling a PPI prescription rose from about 5.7% in 2002 to 6.7% by 2017. Over-the-counter PPI sales, which these numbers don’t fully capture, add significantly to that figure. Meanwhile, older acid-reducing drugs called H2 blockers have gradually declined in use, dropping from about 2.5% of the population in 2010 to 1.9% by 2019. The overall trend is clear: more people are treating reflux with stronger medications than they were two decades ago.
Long-Term Risks to Keep in Perspective
One concern people have about chronic acid reflux is whether it leads to more serious problems. The most talked-about complication is Barrett’s esophagus, a condition where the lining of the lower esophagus changes in response to repeated acid exposure. Among people with GERD, about 3% develop Barrett’s esophagus. That number is low enough to be reassuring for most people, but high enough to matter in a population where hundreds of millions have reflux. Barrett’s esophagus itself carries a small but real risk of progressing to esophageal cancer, which is why long-standing, frequent reflux symptoms are worth taking seriously rather than just managing with antacids indefinitely.