By Steven Reinberg
TUESDAY, June 23 (HealthDay News) -- Being overweight or obese as a young adult increases the risk for pancreatic cancer, and obesity in middle age is linked with poorer survival from the disease, a new study finds.
Pancreatic cancer is the fourth leading cause of cancer-related death for men and women in the United States. As the number of people who are overweight and obese has increased in the past two decades, evidence has grown that excess body weight is a risk factor for pancreatic cancer.
"The stronger association of excess body weight at earlier adulthood with risk of pancreatic cancer suggests that weight control at younger age should be the primary preventive strategy to reduce the risk of pancreatic cancer," said study researcher, Donghui Li, an associate professor in gastrointestinal medical oncology at the University of Texas M. D. Anderson Cancer Center in Houston.
The report is published in the June 24 issue of the Journal of the American Medical Association.
Li's group collected data on 841 people with pancreatic cancer and 754 healthy people.
They found that people who were overweight between ages 14 and 39 or who were obese between ages 20 and 49 had an increased risk for pancreatic cancer. The association was stronger in men than in women, the researchers noted. Those who were overweight or obese and also smoked had an even greater risk.
"For example, in your 30s, overweight was associated with 60 percent increased risk of pancreatic cancer and obesity was associated with a two- to threefold higher risk of pancreatic cancer," Li said.
The risk of cancer leveled off for those who started to become overweight or obese at age 40, and the risk became nonsignificant for those whose excessive weight gain did not start until after age 50, Li added.
In addition, people who were overweight or obese when they were 20 to 49 years old developed pancreatic cancer two to six years earlier than people of normal weight, the study found.
"The median age of cancer diagnosis was 64 years for those with normal [body-mass index], but was 61 years for overweight patients and 59 years for obese patients," Li said.
The study also found that obesity later in life -- especially within the year before a cancer diagnosis -- was associated with reduced overall survival time for people with pancreatic cancer, Li said.
"For example, the median survival time was 18 months for patients with normal body weights during the year prior to cancer diagnosis, but the median survival time was reduced to 13 months for overweight or obese patients," he said.
Dr. Robert R. McWilliams, an oncologist at the Mayo Clinic and co-author of an accompanying journal editorial, said that if the findings are correct, overweight and obesity have a negative impact on all facets of pancreatic cancer.
"What's notable about this study is that higher BMI has implications throughout the course of pancreatic cancer -- from development to worsened survival," he said.
"This represents another negative impact of rising obesity in our country," McWilliams said.
And it is yet another reason, he said, to maintain a healthy weight, especially for those at higher risk for pancreatic cancer, such as people with a family history of the disease.
"In addition, something associated with obesity apparently drives pancreatic cancer," McWilliams said. "As a scientific community, we need to understand the underlying mechanism. Hopefully, this can lead to future treatment strategies."
The American Cancer Society has more on pancreatic cancer.
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