Longitudinal and regional association between dietary factors and prevalence of Crohn's disease in Japan.

Although a Western diet has been identified as a risk factor for Crohn's disease (CD), there is still controversy surrounding the specific foods that may contribute to the development of the disease. In this study, we examined the association between food intake and the prevalence of CD in Japan, as Japanese patients with CD are known to have limited genetic involvement. We identified changes in food intake associated with an increase in the number of patients with CD by analyzing the per capita consumption of food types from 1981 to 2014. Additionally, we examined the association between CD prevalence and food intake in each prefecture. Finally, the relationship between food intake and estimated age at CD onset was also investigated. Between 1981 and 2014, we observed Increased consumption of meat, eggs, milk and dairy products, oil, and potatoes and decreased consumption of grains, beans, vegetables, fruit, fish, sugar, and seaweed. The annual incidence of CD increased by 1388% over the same period. We found that meat consumption was significantly associated with CD prevalence (β = 0.503, p = 0.0003), while a significant negative correlation was observed between CD prevalence and fruit and vegetable consumption (fruit, β = 0.464, p = 0.0012; vegetables, β = 0.404, p = 0.0023). Furthermore, we estimated that the peak consumption of more meat and less fruit and vegetables and the peak age of CD onset occurred within the age range of 20-24 years. Our study identified a clear correlation between the consumption of meat, fruits, and vegetables and the prevalence of CD in Japan. Additionally, we found an association between meat, fruit, and vegetable consumption and the age at CD onset.