Digestive diseases encompass more than 40 acute and chronic conditions of the gastrointestinal tract ranging from common digestive disorders to serious, life-threatening diseases. More than 34 million Americans are afflicted with diseases of the digestive system, 20 million of whom have chronic disorders. It is estimated that 8% of the U.S. population have chronic digestive diseases, 6% have acute episodes of digestive diseases and 43% have intermittent digestive disorders, leaving 43% unaffected. As a group, the digestive diseases account for 8%-9% of total U.S. mortality. 60% of digestive disease mortality is due to malignant neoplasms and 40% to nonmaligant causes, chief of which is cirrhosis of the liver. Digestive diseases are the second leading cause of disability due to illness in The U.S., with more than 2 million Americans impaired to some degree. It is estimated that 400,000 persons are completely disabled by digestive diseases and 1.2 million people are limited in the work they perform due to digestive diseases. Digestive diseases are the leading cause of time lost from work for male employees, and account for 15% of all absences from work among workers ages 17-64 years. The total economic cost associated with digestive diseases has been estimated at more than $50 billion annually.
Incidence and Prevalence
Digestive System Cancer
Of the 2,047,000 deaths from all causes in the U.S. in 1984, 22% or 452,470 deaths were due to cancer. 25% of all cancer deaths, or 115,240 deaths, were due to cancers of the digestive organs and peritoneum.
Colorectal cancer is the most common cancer of the digestive organs, accounting for over 60% of all digestive organ cancers. The American Cancer Society estimates there to be 140,000 new cases of colorectal cancer in the U.S. in 1986.
Causing an estimated 60,000 deaths in 1986, colorectal cancer is the second leading cause of cancer mortality in the U.S. (behind lung cancer).
About 20 million Americans, or almost 10% of the population, have or have ever had an ulcer of the stomach or duodenum.
Approximately 4 million Americans currently have ulcers of the stomach or duodenum.
In 1984, there were 6,780 deaths in the U.S. from ulcers of the stomach and duodenum, a 7% increase over 1983.
Although duodenal ulcer is 3-4 times more common than gastric ulcer clinically, autopsy studies indicate the incidence of duodenal and gastric ulcers to be nearly equal.
In 1984, 26,750 people died from cirrhosis and chronic liver disease in the U.S. Chronic liver disease and cirrhosis ranked 9th in age-adjusted death rates in the U.S. in 1984, with a rate of 9.8 deaths per 100,000 population.
Among those ages 45-54 years, cirrhosis and chronic liver disease is the 5th leading cause of death behind cancer, heart disease, accidents and strokes, according to provisional 1984 figures.
There are more than 10 million alcoholics in the U.S. 75% of all deaths attributable to alcohol are due to cirrhosis of the liver.
The American Liver Foundation estimates that 8,000 deaths from cancer of the liver occur each year, including 900 that are related to hepatitis B.
According to the American Liver Foundation, there are 200,000 new cases of hepatitis B annually in the U.S. and 250 deaths from the acute infection. It is estimated that there are 1 million chronic hepatitis B carriers in the U.S.
Biliary atresia is an uncommon congenital defect in the development of the biliary tract that may result in obstruction of the bile ducts and subsequent liver disease. The incidence of biliary atresia is approximately 1 in 20,000 live births.
Primary biliary cirrhosis is a slow progressive liver disease of unknown etiology that affects 1 in 10,000 individuals, most commonly middle-aged women.
It is estimated that 25 million persons in the U.S. have gallstones. Among those 55-65 years of age, 10% of men and 20% of women have gallstones.
Each year in the U.S., about 1 million new cases of gallstones are discovered and about 500,000 gallbladders removed.
In 1984, 3,260 deaths were attributed to gallstones and other diseases of the gallbladder.
Inflammatory Bowel Disease
An estimated 2 million Americans suffer from the inflammatory bowel diseases, Crohn's disease or ulcerative colitis.
The average annual incidence of ulcerative colitis in the U.S. has been estimated at 5.7 per 100,000, while the incidence of Crohn's disease has been estimated at 4.8 per 100,000.
The worldwide prevalence of ulcerative colitis ranged from 40-100 per 100,000 in 1980, while the worldwide prevalence of Crohn's ranged from 10-100 per 100,000.
An estimated 200,000 children under the age of 16 may suffer from Crohn's disease and ulcerative colitis.
About 10% of persons over 40 years of age and 50% of those over 60 years of age have diverticulosis.
In 1980, there were 3,135 deaths in the U.S. due to diverticula of the intestine.
Other Digestive Diseases
About 50,000-80,000 cases of acute pancreatitis are diagnosed in the U.S. each year. Chronic pancreatitis affects about 20,000-50,000 people in the U.S.
Wilson's disease is a rare disorder of copper metabolism with an estimated worldwide prevalence of 1 in 200,000 population.
Some reports have suggested that as many as 20% of North Americans may have hiatal hernias.
Digestive Disease Mortality
Of the 189,558 total deaths from all digestive diseases in 1975, 56.3% were due to malignant neoplasms, followed by 16.9% due to cirrhosis and esophageal varices, 3.9% due to ulcer disease, 3.5% due to peritonitis and other intestinal diseases, 2.7% due to vascular disorders affecting the digestive system and 2.3% due to gallbladder and biliary disease.
Age-adjusted mortality rates for cancers of the digestive system have decreased 33% for all persons from 1950-1983. The decline in digestive system cancer death rates was more evident among white females ( – 41%) and white males ( – 29%) than among Black females ( – 14%) and Black males ( + 3%).
From 1950-1983, mortality rates for cirrhosis and chronic liver disease increased about 20%. For white males, the increase was 16%; for white females, 3%; whereas for Black males the increase was 2.6 times and for Black females 1.9 times the 1950 rates.
Risk Factor Prevalence
Demographic Risk Factors
According to a 1980 National Health Interview Survey, the following chronic digestive diseases were reported more commonly by females than by males: gallbladder condition (2.8 female/male ratio), gastritis and duodenitis (1.3 f/m), diverticulosis (3.6 f/m) and frequent constipation (3.2 f/m).
The same survey showed no sexual predominance for ulcer of the stomach and duodenum; however, a male predominance was noted for hernia of the abdominal cavity (1.1 male/female ratio) and for functional and symptomatic upper gastrointestinal disorder (1.3 m/f).
Racial differences in the prevalence of lactase malabsorption exist, as 2%-8% of white adults of Scandinavian or Western European descent have low intestinal lactase levels, compared to 60%-80% of American Blacks, Jews and Indians and more than 90% of American Orientals.
There are an estimated 300,000 new cases of duodenal ulcer annually in the U.S., with a 2:1 male predominance. The peak age of onset for duodenal ulcer is between ages 30 and 50. Duodenal ulcer is less common among women of childbearing age, as the ratio of men to women is 8:1.
There is a 2-fold increase in peptic ulcers among smokers as compared with controls and the incidence of peptic ulcer increases with increasing numbers of cigarettes smoked.
In the 19th century, ulcer disease was about 5 times more common among women than men. The ratio became equal about 1915, after which a male predominance began that led to the current male/female ratio of 2:1.
Native American women have an incidence of ulcer disease that is about 4 times that of American women in general.
Age-adjusted death rates in 1983 for cirrhosis and chronic liver disease were more than 2 times as high among males than females and more than 1.7 times higher among Blacks than whites. Those death rates (per 100,000 population) were 10.2 for all persons, 13.4 for white males, 6.0 for white females, 22.8 for Black males and 10.8 for Black females.
Among persons aged 55-65 years, gallstones are about 2 times as common among women as men.
The incidence of gallstones is higher among certain ethnic groups such as the Pima Indians. It is estimated that 70% of Pima women over 25 have cholelithiasis.
Obesity, with its associated increase in biliary cholesterol, is a major etiologic factor in cholesterol gallstone formation.
Inflammatory Bowel Disease
The inflammatory bowel diseases of ulcerative colitis and Crohn's disease may occur at any age, but the bulk of cases are identified between ages 15 and 35 years.
Inflammatory bowel diseases occur at about the same frequency in males and females.
There is a higher prevalence of inflammatory bowel disease (IBD) among first-degree relatives of patients with IBD (15%) than in the general population (0.1%).
Inflammatory bowel disease (ulcerative colitis and Crohn's disease) is 4-6 times more common among Jews than in the general population, while Blacks and Spanish-Americans have a lower incidence of inflammatory bowel disease than the population at large.
The prevalence of diverticulosis increases with age to include about 50% of those over 60 years of age. Diverticulosis is more common among women than men.
Dietary fiber is thought to protect against diseases of the colon including diverticulosis, polyps and cancer; however, elucidation of the exact role of dietary fiber in these disease requires further study.
Health Services Utilization
About 15% of all admissions to general hospitals in the U.S. and 12% of admissions to VA hospitals are for digestive diseases.
In 1984, digestive diseases were the underlying cause for about 25% of all surgical operations, excluding obstetrical procedures.
In 1984, digestive disease was the second leading hospital discharge diagnosis with 4.3 million discharges or 12% of all discharges. Diseases of the circulatory system, including hypertension, heart disease and stroke, ranked higher with 15% of discharges in 1984.
According to the 1984 National Hospital Survey of nonfederal hospitals, included in the total of 4.3 million hospital discharges for digestive diseases were 327,000 diagnoses of ulcer disease (55% male), 266,000 diagnoses of gastritis and duodenitis (59% female), 270,000 diagnoses of appendicitis (57% male), 440,000 diagnoses of inguinal hernia (89% male), 540,000 diagnoses of noninfectious enteritis and colitis (61% female) and 488,000 diagnoses of cholelithiasis (71% female).
In 1975, there were an estimated 5,466,040 hospital discharges for digestive diseases, accounting for 14.7% of all discharges. The leading diagnoses for hospitalizations due to digestive diseases were hernia (15.4% digestive disease hospital discharges); gall-bladder and binary diseases (11.7%); intestinal infectious diseases (9.7%); diseases of the esophagus, stomach and duodenum other than ulcer (8.1%); ulcer disease (7.1%); lower GI symptoms (6.3%); appendicitis (5.4%) and malignant neoplasms (5.1%).
Of the 48.2 million physician office visits for the treatment of digestive diseases in 1976, 59.2% were by females and 40.8% by males. These office visits were spread throughout all ages, as 14.4% occurred to those under 15 years, 16.7% occurred to those 15-24, 29.6% to those 25-44, 25.0% to those 45-64, 14.3% to those 65 and over.
In 1982, there were 619,000 people discharged from U.S. hospitals with a diagnosis of ulcers. There were 82,000 ulcer operations that year.
In 1983 in the U.S., there were approximately 647,000 endoscopic examinations of the large intestine, a 33% increase since 1979. 61% of these exams were performed on females.
In 1985, 674 liver transplantation procedures were performed worldwide. From 1963, when the first liver transplant was performed, to June 1983, about 540 liver transplants were performed in the U.S. and Western Europe.
The 1984 National Hospital Discharge Survey reported that there were 5.9 million operations on the digestive system, including 257,000 procedures for partial gastrectomy and resection of intestine (54% female), 294,000 appendectomies excluding incidental (54% male), 131,000 hemorrhoidectomies (53% female), 469,000 repairs of inguinal hernias (88% male) and 308,000 procedures to divide peritoneal adhesions (87% female).
The National Commission on Digestive Diseases estimated that the total economic cost associated with digestive diseases is more than $50 billion annually.
Alcoholism, the most common cause of liver disease in the U.S., results in an annual cost of alcohol-induced hepatic injury of more than $2 billion.
It is estimated that between $200–$500 million is spent annually on nonproprietary laxatives in the U.S.
$201.5 million was appropriated for digestive disease activities at the National Institutes of Health for 1986. In addition, $6.5 million was appropriated for digestive disease activities at the National Institute on Alcohol Abuse and Alcoholism, a unit of the Alcohol, Drug Abuse and Mental Health Administration.