Obesity is a known risk factor for pancreatic cancer, but Houston researchers have found that people who took on excess weight in early adulthood or even their teens are at greatest risk.

In a study published in Wednesday's issue of the Journal of the American Medical Association, University of Texas M.D. Anderson Cancer Center scientists reported adults who were overweight between 14 and 19 years old had a 60 percent higher risk of developing pancreatic cancer later in life, and those who were obese in their 20s and 30s had a two to three times' higher risk.

"This shows the importance of weight control in one's younger years to reduce pancreatic cancer risk," said Donghui Li, a professor in M.D. Anderson's department of gastrointestinal medical oncology. "The development of pancreatic cancer is still something of a mystery, but this suggests a preventive step people can take when they're younger."

Weight, stages of life

The study is the first in pancreatic cancer to look at the association between pancreatic cancer and excess weight at different stages of an individual's life span. The method is more common in diabetes studies.

The researchers also found adults overweight or obese around the time of diagnosis have shorter survival times than normal-weight patients. Normal-weight patients in the study lived an average of 18 months after diagnosis, whereas heavier patients lived 13 months.

Li's team matched 841 pancreatic cancer patients and 754 healthy people by age, sex and race. Participants were interviewed about their height and weight starting at ages 14 to 19 until the year prior to their recruitment in the study, as well as their alcohol use, smoking and family history.

The study found the risk of developing pancreatic cancer was not statistically significant when participants only became overweight or obese in their 50s.

Smoking also a factor

Pancreatic cancer is the fourth leading cause of cancer death in the U.S. It is diagnosed in more than 42,000 people a year and kills more than 35,000, according to the American Cancer Society. The five-year survival rate is less than five percent.

Obesity and smoking are the major modifiable risk factors associated with the disease. About 25 percent of cases are associated with obesity and 27 percent with smoking.

todd.ackerman@chron.com To see more of the Houston Chronicle, or to subscribe to the newspaper, go to http://www.HoustonChronicle.com. Copyright (c) 2009, Houston Chronicle Distributed by McClatchy-Tribune Information Services. For reprints, email tmsreprints@permissionsgroup.com, call 800-374-7985 or 847-635-6550, send a fax to 847-635-6968, or write to The Permissions Group Inc., 1247 Milwaukee Ave., Suite 303, Glenview, IL 60025, USA.