A long-term Norwegian study reveals the number of people who experience acid reflux at least once a week has gone up by nearly 50% in the last 10 years, with women appearing to be more susceptible to the condition than men. The findings raise concerns that this will lead to an increase in cancer of the oesophagus, a once rare but now more common malignancy that is very difficult to treat. The researchers write about their findings in the online first issue of the journal Gut, published on 21 December.

Acid reflux, also known as gastro-oesophageal reflux, is where the stomach contents, which includes food and acidic digestive juices, escape upwards into the gullet or oesophagus. This can irritate the oesophagus and cause heartburn and other symptoms.

The condition is linked to an increase of gullet or oesophageal cancer, which is difficult to treat successfully. Rates of this cancer are rising rapidly in developed countries.

For the study, lead author Eivind Ness-Jensen of the Norwegian University of Science and Technology in Levanger, and colleagues, tracked the digestive health of nearly 30,000 people taking part in the Norwegian Nord-Trøndelag Health Study (the HUNT study), which takes its data from regular health surveys of a representative sample of the Norwegian population.

The participant data covers an average of 11 years between 1995-6 and 2006-9. When they analyzed it, the researchers found that:

  • Over the study period, the prevalence of any acid reflux symptoms rose 30% (from 31.4% to 40.9% of participants), while the more severe symptoms rose by 24% (from 5.4% to 6.7%).
  • The number of people who experienced the symptoms at least once a week rose by 47% (from 11.6% to 17.1%).
  • This increase was apparent in both men and women and across all ages, although middle age appears to be when the most severe symptoms occurred.
  • Nearly all (98%) of participants with severe symptoms experienced them and/or used medication to treat them at least once a week, compared to only 31% of those with mild symptoms.
  • The average annual rate of experiencing any acid reflux symptoms was just over 3%. For severe symptoms it was 0.23%.
  • Women under 40 were the least likely to have acid reflux, but, unlike men, they were more likely to develop symptoms as they got older. Women aged 60 to 69 were the most likely to have severe symptoms.
  • Acid reflux can spontaneously disappear without the help of medication, but in this study, this occurred each year in only 2% of those participants with symptoms.
  • Again, women under 40 were the group most likely to experience spontaneous loss of symptoms without antireflux medication. And while there was a suggestion that this diminished with age in both sexes, it was most evident among women.

The authors note that use of anti-reflux medication could not explain these patterns, and neither could pregnancy, when acid reflux often occurs.

One explanation for acid reflux becoming more common could be the increase in the number of overweight and obese people. Being overweight is a risk factor for acid reflux. Also, the singular patterns in women could be linked to the use of hormone replacement therapy (HRT), note the authors.

They warn that:

“The increasing prevalence of [acid reflux] is alarming, because it will most likely contribute to the increasing incidence of adenocarcinoma of the oesophagus in the western population.”

Written by Catharine Paddock PhD