Gastroduodenal Diseases

Functional dyspepsia (FD) is categorized into postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). FD is 1.36–2.71 times more common in women than in men in the studies of outpatient clinic, and women demonstrated a higher prevalence in large-scale studies of health checkup participants. Usually, the rate of Helicobacter pylori (H. pylori) infection is significantly higher among males than females after the age of 16. The prevalence of atrophic gastritis and intestinal metaplasia is also higher in males than in females. Furthermore, duodenal and gastric ulcers were twice as common among males as females. However, the incidence of nonsteroidal anti-inflammatory drug (NSAID)-induced gastric ulcers has recently increased among females who take NSAIDs more than males, resulting in gastric ulcers becoming relatively more prevalent and attenuating sex/gender differences. The Lauren classification categorizes gastric cancer (GC) into two types: the intestinal-type and the diffuse-type. A higher prevalence of GC in males than in females can be observed throughout the world, but younger patients with GC are more likely to be female, have the diffuse and undifferentiated types, and present with advanced GC (AGC). Older patients with GC are more likely to be male, have the intestinal-type, and present with simultaneous tumors. A multivariate analysis of the risk factors of diffuse-type GC found that female sex, age under 50, family history of GC, and smoking were independent risk factors. In females, the diffuse-type accounts for most cases before menopause, but the proportion of the intestinal-type becomes similar to that in males 20 years after menopause, indicating that female sex hormones suppress the incidence of intestinal-type GC. Interestingly, the risk of cardiac GC is associated with obesity. This elevated cardiac GC risk related to obesity being greater in males than in females with the following reasons: First, increased concentrations of female hormones in obese females might have a protective effect against GC. Second, different prevalence of cardiac GC precursors such as Barrett’s esophagus is higher in males than in females. Meanwhile, being underweight increases the risk of noncardiac GC, especially in females mainly in Asian countries.