between diagnoses; however, all 17 diseases affect older patients. Some, such as colorectal cancer, pancreatic cancer, and diverticular disease, are much more likely to occur in older patients, and thus the burden is highest in that age group. A conservative estimate of the contribution of older patients is that 35%–40% of geriatric patients (or 45–50 million individuals) will have one or more GI symptoms or health issues in any year. A large number will be related to constipation (or other problems of defecation) and reflux disease, based on office reports in primary care and specialist offices. This would result in a burden of more than 10 million office visits per year at the current percentage of older patients, which closely matches the numbers reported in a recent survey of gastroenterology resource utilization.5 These numbers may increase by as much as 2–3 times this amount as the percentage of individuals older than 65 years in the population increases to more than 20%. The cost of treating GI disease in older patients exceeds $300 million today and will likely increase by at least 2- to 3-fold as older patients live longer. Shift in the Prevalence and Incidence of GI Disease With Aging In addition to well-described conditions such as colon cancer and GERD that affect older patients, it is becoming clear that other conditions usually believed to be present primarily in young patients are significant problems in geriatric patients. This includes diarrhea and irritable bowel syndrome (IBS) symptoms that seem to present de novo in patients older than 70 years. As the population successfully ages into the eighth and ninth decades of life, gastroenterologists are likely to see patients with longstanding chronic diseases, such as viral hepatitis and inflammatory bowel disease, occurring with higher than expected prevalence in geriatric patients. Age-appropriate treatments will need to be developed (eg, safer drugs to treat IBS and chronic diarrhea). New procedures and treatments will need to be evaluated in geriatric populations with appropriate comorbidities. Physiology of Aging General Principles of Aging As the “baby boom” generation reaches the geriatric threshold, new questions are being raised about the process of aging. Is decline in function inexorable, or can function be maintained throughout one’s life? Is the loss of function related to “normal aging,” or is superimposed disease the culprit? What is “normal aging”? There has been a dramatic increase in research funding available for aging research, primarily due to the fact that the answers to these questions are likely to have a major impact on the well-being and healthy aging of the world’s population for decades to come. Physiologic changes in GI function do occur with age. Current research suggests that this process may accelerate dramatically over the age of 70 years. Women experience a rapid change in physiologic function surrounding the involution of ovarian function that defines the menopause. Although there is no comparable event during aging, there is considerable evidence that a threshold exists in the geriatric age range, beyond which there is significantly increased likelihood of impairment and disease. The actual age varies between individuals; however, most people experience this “geripause” somewhere between the ages of 60 and 75 years. The term “geripause” has been used to describe the age threshold beyond which significant changes in physiology occur that result in impaired