The muscular wall of the colon grows thicker with age, and this may reflect the increasing pressures required by the colon to eliminate feces.

What causes diverticula?

As the body ages, the outer layer of the intestinal wall thickens. This causes the open space inside the colon to narrow. Stool moves more slowly through the colon, increasing the pressure. Hard stools (such as those produced by a low fiber diet) or a slower "transit time" through the colon can also increase pressure. Frequent, repeated straining during bowel movements also increases pressure and may contribute to the formation of diverticula.