Review article: prevalence and epidemiology of gastro-oesophageal reflux disease in Japan.

The prevalence of gastro-oesophageal reflux disease (GERD) in Asian populations is reported to be lower than that in Western populations. However, recent epidemiological studies suggest that the incidence of the disease is increasing, especially in Japan. Endoscopic studies show that the overall prevalence of reflux oesophagitis among the adult population in Japan is in the region of 14-16%. This is similar to the figure reported in Western countries. The increasing prevalence in Japan may be due to a number of factors including increasing awareness of the condition and improved diagnostic techniques. The majority of the diagnosed cases in Japan are mild and these account for the increase in prevalence of the condition. In contrast to the West, where the condition is more prevalent in male members of the population, there is a high incidence of GERD in elderly females in Japan. The increased incidence of kyphosis and osteoporosis in this population may lead to the development of hiatus hernia, a condition known to exacerbate the development of reflux disease. Furthermore, Japanese patients with endoscopically diagnosed GERD appear to be less likely to complain of typical reflux symptoms, such as heartburn and acid reflux than their Western counterparts. In view of the known relationship between asymptomatic GERD and the development of oesophageal cancers there is a strong case for increased vigilance in the detection of GERD in the Japanese population.