Table 1 Operationalising the diagnosis of Gastroesophageal reflux disease (GERD), Functional dyspepsia (FD), and Irritable bowel syndrome (IBS) in terms used in the survey

GERD

 A condition that develops when reflux of the stomach contents causes troublesome symptoms and/or complications. Must include at least one of the two criteria:

  • Mild symptoms occurring more than 1 day a week or moderate to severe symptoms at least once a week.

  • Impaired sleep at least to some extent, or impaired daily activities at least to a lesser extent and mild symptoms occurring at least once a week, or moderate to severe symptoms at least 2–3 times a month.

FD

 Must include one or more of the following:

  • Uncomfortably full after a regular-sized meal more than 1 day/week in the last 3 months. Onset more than 6 months ago.

  • Unable to finish a regular-sized meal more than 1 day/week in the last 3 months. Onset more than 6 months ago.

  • Pain or burning in the middle of the abdomen at least 1 day/week in the last 3 months. Onset more than 6 months ago.

IBS

 Must include:

 Pain or discomfort in the abdomen at least 2 to 3 days/month in the last 3 months with onset at least 6 months ago. For women, the pain must not occur only during menstrual bleeding. And at least 2 of the 3 following criteria:

  • Pain or discomfort gets better after bowel movements at least sometimes.

  • Onset of pain or discomfort associated with more frequent stools at least sometimes or onset of pain, or discomfort associated with fewer stools at least sometimes.

  • Onset of pain or discomfort associated with loose stools at least sometimes, or onset of pain or discomfort associated with hard stools at least sometimes.