Being overweight before the age of 50 may significantly increase the risk of death from pancreatic cancer, a study has found.
Pancreatic cancer is relatively uncommon, accounting for just over three per cent of all new cancer cases. However, it is an extremely deadly type of cancer, with a five-year survival rate of just 8.5 per cent, researchers said.
"Pancreatic cancer rates have been steadily increasing since the early 2000s," said Eric J Jacobs, senior scientific director of Epidemiology Research at the American Cancer Society in the US.
"We've been puzzled by that increase because smoking -- a major risk factor for pancreatic cancer -- is declining," he said in a statement.
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 risk of pancreatic cancer during a typical lifespan, Jacobs said.
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.
The team examined data from 963,317 US adults with no history of cancer. 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 body mass index (BMI), a measure of weight relative to height, 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 increased risk of dying of pancreatic cancer, but this increase in risk was largest for BMI assessed at earlier ages.
While 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, Jacobs said.
Jacobs said the study results indicate that excess weight could increase risk of death from pancreatic cancer more than previously believed.
"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 which would help prevent many other diseases as well," Jacobs said.