Pancreatic cancer rates have increased by nearly a fifth since 1999.
Smoking is a known cause of this often-fatal disease yet the number of smokers has reached a record low while pancreatic cancer rates continue to climb.
Could the obesity epidemic now be fuelling the increase in pancreatic cancer rates? How does it do this?
Obesity causes inflammation, which encourages cell growth and can promote cancer cell mutations.
Unsurprisingly, people who have a BMI over 30 before the age of 50 are at a 25% greater risk of dying of pancreatic cancer.
“We’ve been puzzled by that increase because smoking – a major risk factor for pancreatic cancer – is declining,” Dr Eric Jacobs, scientific director at the American Cancer Society, and co-author of the new study has said.
Although pancreatic is one of the more poorly understood forms of cancer, smoking is a major known risk factor – think of Patrick Swayze.
Excess body weight is a major risk factor for many forms of cancer – uterine, oesophageal, stomach, kidney, liver, certain brain tumours, plus pancreatic and colorectal cancers and multiple myeloma.
“Increased weight in the US 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,” Dr Jacobs explained.
But his new study changes that by looking at excess weight gain when people are younger. Dr Jacobs and his team analysed data on 963,317 people without a history of cancer, starting in 1982, to see if those who were overweight before the age of 50 would have higher odds of going on to develop pancreatic cancer.
It turns out people who were overweight earlier in life were more likely to die of pancreatic cancer.
For example, a person who had been 32lb overweight between the ages of 30 and 49 was at a 25% greater risk of dying of pancreatic cancer than someone who was a healthy weight at that age.
So the earlier in life someone gains the extra pounds, the more their risks of dying from the disease.
Based on these results, Dr Jacobs estimates that excess weight will be the driving factor in up to a third of pancreatic cancer deaths for people born between 1970 and 1974.
“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,” he said.