Yes. The incidence of diverticular disease in the US increases with age: diverticuli are found in as many as 1/3 people by age 60, and app 1/2 of all people 80 and over. It is believed that our high red meat/low fiber diets contribute to this high incidence. Of course, only a small subset (~20%) of people with diverticuli ever develop diverticulitis.
More common. In the 40 years old and above range but does occur in a younger populations. Used to be considered a disease of 50 years and above but there has been a trend to presenting at younger ages. May be related to more fast food ingestion, more caffeine (starbucks) intake, poor rest and poor eating habits.