Preliminary analyses of these data on food frequency suggested that "Western" foods (animal products such as beef and cheese) were associated with higher risks of idiopathic sudden deafness, and that "Japanese" foods (plant products such as Chinese cabbage and green tea) were associated with lower risks of this condition. So, we created an index that corresponded to a diet comprising mainly Western foods, and a second index that corresponded to a diet comprising mainly Japanese foods based on factor analysis.