The Best Years in Life Diverticulitis, an inflammatory disease of the colon caused by infection, is an age related illness common in individuals over 40 in industrialized countries. As an individual ages, the risk of getting this disease increases. Whereas about 10% of Americans over the age of 40 suffer from diverticulitis, the number increases to around 50% of Americans over the age of 60. Diverticulitis develops from the condition known as diverticulosis. Diverticulosis occurs when pouches, called diverticula, form outside of the colon . . . Read More.