Diverticulitis tends to occur in people who eat low-fiber diets.

It is difficult to determine the exact incidence of diverticulosis (the formation of pouches in the wall of the large intestine) because most people who have colon pouches do not have symptoms. Generally, diverticulosis becomes more likely with age. It occurs in fewer than 10% of people under age 40. Of people over age 80, between 50% and 66% have the condition.¹

About 20% of the people who have been diagnosed with diverticulosis develop diverticulitis, which occurs when the pouches along the large intestine become inflamed or infected. Men and women are affected almost equally.²