Demography of aging and the epidemiology of gastrointestinal disorders in the elderly.

Population aging is a global phenomenon. It is estimated that there were 600 million people in the world aged 60 and over in 2000 and that there will be 1.2 billion by 2025. People aged 65 and over comprise 16% of the population of Europe. About half of the world's elderly population live in the developing world. Many of the gastrointestinal disorders seen in specialist practise show age-specific incidence and prevalence rates that increase substantially with increasing age. In this review, hospitalization rates for gastroenterological disorders in England are presented by age to demonstrate gradients with age. Some of the disorders, such as colorectal cancer, appendicitis, diverticular disease and inflammatory bowel disease, became common in developed countries in association with economic development and changes in lifestyle. As the developing world becomes more urbanised and westernised, disorders that are now rare in the developing world will probably become much more common.