超重或肥胖使人患癌症几率增大

Being overweight and obese puts people at greater risk of developing 10 of the most common cancers, according to research in the Lancet medical journal.

医学期刊《柳叶刀》上的一项调查显示，超重与肥胖会使人患10中常见癌症飞几率大大增加。

Scientists calculated individuals carrying this extra weight could contribute to more than 12,000 cases of cancer in the UK population every year. 

They warn if obesity levels continue to rise there may be an additional 3,700 cancers diagnosed annually. 

The study of five million people is the largest to date to confirm the link.

Large numbers

Doctors often warn being overweight can increase the risk of developing cancer, but this study highlights those forms of the disease where the risk is greatest.

Led by scientists from the London School of Hygiene and Tropical Medicine researchers gathered data on five million people living in the UK, monitoring changes to their health over a period of seven years.

They found each 13-16kg of extra weight an average adult gained was linked firmly and linearly to a greater risk of six cancers.

How big this risk was varied depending on tumour type. 

 Cancer of the uterus had the highest increased risk

 gallbladder（胆囊） 

 kidney 

 cervix（子宫颈） 

 thyroid（甲状腺） 

 leukaemia（白血病） had the lowest rise in risk.

People who had a high body mass index (calculated using weight and height) were also more likely to develop cancer of the liver, colon, ovaries, and post-menopausal breast cancer. 

But the effects for these cancers were less clear-cut and were influenced by individual factors such as the menopause.

Researchers say though obesity was associated with the development of the most common cancers - which represent 90% of the cancers diagnosed in the UK, some showed no link at all.

And there is some evidence to suggest a higher BMI is associated with a lower chance of getting prostate cancer.