超重或导致患胰腺癌的风险增加

Pancreatic cancer rates have increased by nearly a fifth since 1999.

自1999年以来，胰腺癌的发病率已增加近五分之一。

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?

众所周知，吸烟是这种常见致命疾病的诱因之一，但现而今，吸烟人数已达历史最低，而胰腺癌的发病率仍在继续攀升。肥胖症是否也在助推胰腺癌发病率的上升？它又是如何做到的？

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.

肥胖会引发炎症，从而促进细胞生长、加快癌细胞突变。果不其然，50岁以前身体质量指数超过30的人因胰腺癌而亡的风险会增加25%。

"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.

"我们一直对胰腺癌发病率上升一事感到困惑，因为吸烟--胰腺癌的主要危险因素--正在下降，"美国癌症协会的科学主任兼本项新研究的合著者埃里克·雅各布（Eric Jacobs）博士说道。

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.

尽管人们对胰腺癌不太了解，但大家都知道吸烟是其主要的危险因素--想想帕特里克·斯威兹（Patrick Swayze）吧。超重是多种癌症的主要危险因素--子宫癌、食道癌、胃癌、肾癌、肝癌、脑瘤癌、胰腺癌、结肠直肠癌，以及多发性骨髓瘤。

"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.

"美国人口体重增加引起了我们的猜疑，但先前的研究已经表明--超重只与胰腺癌风险相对小幅度增加相关，看起来并不能完全解释近期胰腺癌患病率增加一事，"雅各布博士解释道。

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.

但他的新研究通过观察人们年轻时的增重情况改变了这一说法。雅各布博士和他的团队分析了自1982年以来没有癌症史的963317人的数据，以查看50岁以前超重是否与后期患胰腺癌风险更高相关。

It turns out people who were overweight earlier in life were more likely to die of pancreatic cancer.

事实表明，年轻时超重的受试者更有可能死于胰腺癌。

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.

比如，30至49岁超重32磅的一名受试者死于胰腺癌的风险比这一年龄段体重正常人士高25%。

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.

基于这些结果，雅各布博士估计：三分之一出生于1970至1974年的人群将受超重驱动患胰腺癌而亡。