AACR 2019: Higher BMI Before Age 50 May Increase Risk of Pancreatic Cancer
A higher body mass index (BMI) before age 50 may be more strongly associated with pancreatic cancer mortality risk than excess weight at older age, according to the results of a study presented by Jacobs et al at the American Association for Cancer Research (AACR) Annual Meeting 2019 (Abstract 3281).
“Pancreatic cancer rates have been steadily increasing since the early 2000s. We’ve been puzzled by that increase because smoking—a major risk factor for pancreatic cancer—is declining,” said the study’s lead author, Eric J. Jacobs, PhD, Senior Scientific Director of Epidemiology Research at the American Cancer Society in Atlanta, in a statement.
“Increased weight in the U.S. population is a likely suspect, but previous studies have indicated that excess weight is linked with only a relatively small increase in risk, which doesn’t look large enough to fully explain recent increases in pancreatic cancer rates,” explained Dr. Jacobs.
Dr. Jacobs said, however, that most previous studies on the link between weight and pancreatic cancer were based on weight measured in older adulthood, which may be less informative because it could reflect body fat gained too late in life to influence the risk of pancreatic cancer during a typical lifespan. In this study, researchers sought to find out if excess weight measured earlier in adulthood might be more strongly linked to pancreatic cancer risk than excess weight measured at older ages.
Methods and Findings
Researchers examined data from 963,317 American adults with no history of cancer who enrolled in the American Cancer Society’s Cancer Prevention Study II, a nationwide study of cancer mortality that began in 1982 and followed participants through 2014. All participants reported their weight and height just once, at the start of the study—when some were as young as 30 while others were in their 70s or 80s. The researchers used this information to calculate BMI as an indicator of excess weight.
During the follow-up period, 8,354 participants died of pancreatic cancer. As expected, higher BMI was linked with an increased risk of dying of pancreatic cancer, but this increase in risk was largest for BMI assessed at earlier ages. An increase of 5 units of BMI—about 32 lb for a 5-ft, 7-in adult—was associated with a 25% increased risk in those who had their BMI assessed between ages 30 and 49; 19% increased risk in those assessed between 50 and 59; 14% increased risk in those assessed between ages 60 and 69; and 13% increased risk in those assessed between ages 70 and 89. Dr. Jacobs noted that although the study only had information on deaths from pancreatic cancer, the disease is nearly always fatal, so results are expected to be similar to those for new diagnoses of pancreatic cancer.
Study Implications
Dr. Jacobs said the study results indicate that excess weight could increase risk of death from pancreatic cancer more than previously believed. Furthermore, he noted that recent generations are reaching early middle age with more excess weight than earlier generations did. Therefore, he anticipates that excess weight will explain a larger proportion of pancreatic cancer risk in the future as newer and heavier generations reach the older ages when pancreatic cancer typically occurs.
“Our results strongly suggest that to stop and eventually reverse recent increases in pancreatic cancer rates, we will need to do better in preventing excess weight gain in children and younger adults, an achievement that would help prevent many other diseases as well,” Dr. Jacobs said.
Disclosure: This study was funded by the American Cancer Society. The study authors’ full disclosures can be found at abstractsonline.com.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
