Why is symptomatic gastroesophageal reflux a rarity in Chinese?

There is no satisfactory explanation for the observation that symptomatic gastroesophageal reflux is extremely rare in oriental peoples. Indeed, the condition is so uncommon in Hong Kong that no word for 'heartburn' exists in the Cantonese language. Studies were undertaken in patients with symptoms suggestive of reflux disease (10 Chinese, 20 British) and in asymptomatic normal subjects (15 Chinese, 20 British). At station pull through manometry fasting lower esophageal sphincter pressure (LESP) was obtained by subtracting end expiratory intragastric pressure from end expiratory high pressure zone pressure. LESP was taken as the mean value of those obtained with lateral tube orifices on 3 station pull through measurements. We employed a tethered pH sensitive radiocapsule to monitor esophageal pH in fully ambulant subjects, 24 hour studies being undertaken on an outpatient basis using a portable radiotelemetry system. Whilst pH data obtained in normal British subjects was similar to that in asymptomatic Chinese, the basal LESP in the latter was significantly greater (p < 0.001). It seems likely that high basal LESP is related to the low incidence of symptomatic reflux in Chinese subjects.