Differences in peptic ulcer between East and West.

In general, peptic ulcer occurs at equal rates in the East and the West but with marked regional differences in both, even within the same country. In the West, the incidence of peptic ulcer, particularly duodenal ulcer, rose sharply at the turn of the century and has shown a rapid decline in the past three decades. In the East, the rise was equally impressive, but the decline appears to have been delayed, only starting in the past decade. Asians present their ulcer symptoms a decade earlier than Caucasians, and it has been suggested that this early presentation may be attributable to Helicobacter pylori (H. pylori) infection at a younger age. Interestingly, the male-to-female ratio is much higher in the East than in the West, and the duodenal-to-gastric ulcer ratio manifests a much wider variation in Asians than in Caucasians. As in Western countries, peptic ulcer occurrence in the East shows a cyclical trend, with a peak frequency in the winter months. In the West, the placebo healing rate varies widely up to 78%, whereas in the East it is rather consistent at around one-third. These variations in geographical distribution, time trends, sex and ulcer ratios, seasonal rates and behavioral response to placebo treatment indicate that while H. pylori is a major cause of peptic ulceration, other environmental and genetic factors contribute to ulcer formation. The parietal cell mass and acid secretory capacity of Asian patients with duodenal ulcer are only slightly more than half of those of Caucasian patients, which may explain why Asian patients respond equally well to half the standard dose of anti-secretory agents used in Caucasians. H. pylori infection is generally more prevalent in the East than in the West and is more resistant to metronidazole. The response to standard triple therapies for eradication, however, appears to be as effective in the East as in the West.