Effects of environment and lifestyle on gastroesophageal reflux disease.

BACKGROUND Gastroesophageal reflux disease (GERD) is comprised of a spectrum of related disorders, including hiatal hernia, reflux disease with its associated symptoms, erosive esophagitis, peptic stricture, Barrett's esophagus, and esophageal adenocarcinoma. Besides multiple pathophysiological associations among these disorders, they are also characterized by their comorbid occurrence in identical patients and by their similar epidemiologic behavior. The occurrence of GERD is shaped by marked temporal and geographic variations, suggesting the influence of environmental risk factors in the etiology of these diseases. VARIATIONS BY TIME, GEOGRAPHY, AND RACE Between 1975 and 2005, the incidence of GERD and esophageal adenocarcinoma increased fivefold in most Western countries. The incidence of GERD also appears to be rising in the most developed countries of Asia. All severe forms of GERD, such as erosive esophagitis, peptic stricture, Barrett's metaplasia, and esophageal adenocarcinoma, are more common among whites than other ethnic groups. AFFLUENCE AND OBESITY AS RISK FACTORS Barrett's esophagus and esophageal adenocarcinoma tend to occur slightly more often in subjects with higher income. Overweight and obesity contribute to the development of hiatal hernia, increase intra-abdominal pressure, and promote gastroesophageal reflux. Weight gain increases reflux symptoms, whereas weight loss decreases such symptoms. Other risk factors, such as smoking, alcohol, dietary fat, or drugs, play only a minor role in shaping the epidemiologic patterns of GERD. PROTECTION THROUGH HELICOBACTER PYLORI On a population level, a high prevalence of H. pylori infection is likely to reduce levels of acid secretion and protect some carriers of the infection against reflux disease and its associated complications. Several studies have confirmed a lesser prevalence of H. pylori among subjects with than without GERD. Until recently, populations in Africa and Asia may have been protected against the development of GERD and esophageal adenocarcinoma by their higher prevalence of H. pylori infection. CONCLUSION The study of environmental risk factors may provide an opportunity to better understand GERD and develop a means of its prevention.