A medical expert has called for better education of doctors and patients to improve awareness of severe acid reflux, which can cause severe chest pain and heartburn. As many as 500,000 people in Hong Kong could be developing the condition, known as gastroesophageal reflux disease, according to the University of Hong Kong's Li Ka Shing Faculty of Medicine. The estimate was based on a study by the faculty in 2003, which found 10.1 per cent of the city's population suffered from the condition at least once a month. In a second study last year, half of 281 patients surveyed were diagnosed with non-cardiac chest pain, the most common cause of which is acid reflux. The patients - 81 from Hong Kong and 200 from Wuhan in Hubei - were assessed on their level of anxiety and quality of life. Non-cardiac chest pain sufferers reported higher levels of anxiety than cardiac chest pain patients. The condition is caused by the relaxation of the lower oesophageal sphincter, which normally prevents acid from entering the oesophagus. Symptoms include heartburn, acid regurgitation, chest pain and oesophageal injury. Contributing factors include obesity, smoking, alcohol, heavy meals and the use of certain types of drugs, such as aspirin. Benjamin Wong Chun-yu, of the university's department of medicine, expressed concern over the lack of awareness about the condition. 'Most patients experiencing these symptoms may mistake them as stomach problems,' Professor Wong said. 'It's hard to detect ... so the patients may not receive treatments that can really help.' He suggested doctors offer patients drugs known as proton pump inhibitors to reduce stomach acid for two to 12 weeks to find out whether they had the condition. Au-yeung Wai-chung, 59, who suffered for 20 years, said his condition vastly improved after doctors at Queen Mary Hospital treated him with drugs to reduce stomach acid.