Increased Incidence of Inflammatory Bowel Disease in Association with Dietary Transition (Westernization) in Japan

INTRODUCTION: Inflammatory bowel disease has become a global disease, but its key environmental factors still remain unrecognized. This study aimed to clarify the role of dietary transition (westernization) in the increased incidence of inflammatory bowel disease in Japan. METHODS: Annual numbers of new cases of inflammatory bowel disease in Japan over the period from 1965 to 2000 found in a nationwide database compiled by the government and the daily amount of food and nutrient intake per capita for the same period revealed by the National Nutrition Survey have been used to analyze their interrelation. CONCLUSIONS: An increased incidence of inflammatory bowel disease was observed to coincide with dietary westernization in Japan. Our results support the assertion that dietary westernization is a key environmental factor in inflammatory bowel disease.