Obese and overweight young adults at greater risk of pancreatic cancer


Obese and overweight young adults at greater risk of pancreatic cancer

UA scientists looking at the link between BMI over a lifetime and the risk of developing pancreatic cancer found that overweight and obese young adults are more likely to develop the disease, and also that older adults with pancreatic cancer who are obese have a lower overall survival rate.

The study was the work of first author Dr Donghui Li, of the University of Texas MD Anderson Cancer Center in Houston, and colleagues and is published in the 24 June issue of the Journal of the American Medical Association, JAMA.

Cancer of the pancreas is the fourth leading cause of death from cancer for American men and women, and since obesity began to rise steeply in the US in the last 20 years, there is increasing evidence that carrying too much weight is a risk factor for this disease.

But despite this trend, as the authors pointed out in their background information, we don't know very much about the link between excess body weight and risk of pancreatic cancer over a lifetime, nor do we know much about at which stages in that lifetime the key changes in weight occur that could affect the link.

So Li and colleagues investigated this further by looking at two groups of people: one group was 841 patients with pancreatic cancer and the other was a group of 754 healthy people matched to the first group by age, race and sex.

For these groups, height, body weight and other medical histories had already been collected in personal interviews that started at ages 14 to 19 years and then at 10-year intervals thereafter until 12 months before enrolling on the study.

Li and colleagues then explored the links between body mass index (BMI) over a lifetime and three things: the risk of pancreatic cancer, the age the cancer started, and overall patient survival.

A Body Mass Index (the ratio of a person's weight in kilos to the square of their height in metres) of 25 to 29.9 is classed as overweight and a BMI of 30 or more is classed as obese.

Their results showed that:

  • Participants who were overweight from age 14 to 39 or obese from age 20 to 49 were at higher risk of pancreatic cancer regardless of whether they developed diabetes or not.
  • The link between average BMI (for every increase of 5 units) and risk of pancreatic cancer was stronger in men that in women.
  • The link was statistically significant for each age group from age 14 to 69 in men but only from 14 to 39 in women.
  • Ever smokers had a slightly stronger link between average BMI (for every 5 unit increase) and pancreatic cancer risk than never smokers.
  • Among never smokers the chances of pancreatic cancer being linked to being overweight or obese at an early age before diagnosis was estimated at 10.3 per cent.
  • Among ever smokers this figure rose to 21.3 per cent.
  • Pancreatic cancer was diagnosed some 2 to 6 years earlier in participants who were overweight or obese from 20 to 49 years of age.
  • The median (midpoint of the range) age when cancer was diagnosed was 64 for normal weight participants, 61 for for those who were overweight and 59 for those who were obese.
  • Participants who were overweight or obese from age 30 to 79 or up to a year before being enrolled in the study had an overall reduced survival rate for pancreatic cancer, regardless of the stage of the disease and whether the tumor had been operated on.
The authors concluded that:

"Overweight or obesity during early adulthood was associated with a greater risk of pancreatic cancer and a younger age of disease onset. Obesity at an older age was associated with a lower overall survival in patients with pancreatic cancer."

"While our observations require confirmation, they provide support for a role of excess body weight in the development and progression of pancreatic cancer," they added.

"Body Mass Index and Risk, Age of Onset, and Survival in Patients With Pancreatic Cancer."

Donghui Li; Jeffrey S. Morris; Jun Liu; Manal M. Hassan; R. Sue Day; Melissa L. Bondy; James L. Abbruzzese.

JAMA. 2009;301(24):2553- 2562.

Vol. 301 No. 24, June 24, 2009

Obesity & Cancer | Obesity (Video Medical And Professional 2020).

Section Issues On Medicine: Other