Evidence that weight control and exercise may protect against another serious disease -- pancreatic cancer.
Pancreatic cancer, the fourth leading cause of cancer-related death in the United States, is notoriously difficult to detect. In addition, mortality is high; only 4% of patients are still alive five years after diagnosis. Until recently, smoking cigarettes or cigars was the only known, controllable risk factor for pancreatic cancer. However, recent research indicates that some of the lifestyle measures proven to reduce the risk of heart disease, diabetes, and cancers of the breast, prostate, colon, and rectum may also help prevent pancreatic cancer. These measures are especially important for people with a family history of pancreatic cancer.
Symptoms of pancreatic cancer don’t usually appear until the tumor obstructs nearby bile ducts, leading to jaundice, or grows large enough to cause abdominal pressure or pain. Other symptoms of pancreatic cancer can include back pain, nausea, loss of appetite, weight loss, and weakness. Because the pancreas is located deep within the abdomen, tumors cannot usually be palpated (felt upon examination). Furthermore, there are no screening tests to detect pancreatic cancer in its early stages. Thus, pancreatic cancer is generally detected only after symptoms develop and cancer cells have metastasized (spread) to other parts of the body. Occasionally, a tumor that develops near the common bile duct causes jaundice, and this allows early diagnosis. However, 90% of all pancreatic cancers are not diagnosed until the tumor has spread beyond the pancreas.
Risk factors for developing pancreatic cancer include:
smoking -- a two- to threefold increase
age -- more than 80% of new cases develop between the ages of 60 and 80
race -- pancreatic cancer is more common in blacks than in whites
gender -- pancreatic cancer is more common in men
family history -- having more than one close relative with pancreatic cancer increases the risk 18-fold
chronic pancreatitis (inflammation of the pancreas), diabetes, and cirrhosis of the liver are also associated with an increased risk of pancreatic cancer, as is a diet high in meats and fried foods.
Researchers recently examined data from two large population studies (the Health Professionals Follow-Up Study and the Nurses' Health Study) to learn what physical characteristics and lifestyle factors might influence the development of pancreatic cancer. The studies followed 163,689 men and women for 10 to 20 years. During that time, 350 participants were diagnosed with pancreatic cancer. Two new modifiable risk factors emerged: excess weight and physical inactivity.
The likelihood of developing pancreatic cancer was 72% higher in participants who were obese (body mass index, or BMI, of 30 or higher) compared with those who were leaner (BMI of less than 23). Moderate exercise (walking or hiking for about 1.5 hours per week) was associated with a 50% reduction in pancreatic cancer risk. This benefit, which was noted only in those who were overweight, did not require vigorous activity such as running.
It's important to note that these studies are retrospective (based on the recollections of participants) and population based (participants were not randomized to different groups). Therefore, they cannot prove a cause-and-effect relationship. However, since these studies involved large numbers of people and long-term follow-up, the associations are credible and strongly suggest that weight control and exercise may protect against yet another deadly illness.
For more Alerts and Special Reports, please visit the Digestive Disorders Topic page.
