Women, who remain fat for more than decades dramatically raise their risk of getting cancer, a leading scientist has warned. The heavier they are also increases the chance of deadly forms of the disease, data revealed.
On average, every ten years of being overweight upped the odds of cancer by 7 per cent, but for women who were severely obese, the risk of breast cancer rose by 8 per cent every decade – and womb cancer by 37 per cent.
Excess weight is thought to feed at least ten types of cancer, including breast, womb, bowel, pancreatic and kidney tumours.
And British women are among the fattest in Europe, with almost 60 per cent of English females overweight or obese.
Despite advances in medicine, cancer rates are increasing and the disease claims more than 160,000 lives a year in the UK alone.
Melina Arnold, of the International Agency for Cancer Research in Lyon, France, said it is important women are aware that the disease may be fuelled by obesity.
And given that once weight is put on, it is hard to lose, it may be particularly important for young women to watch their waistline.
World Health Organisation researcher Dr Arnold, who worked with US colleagues, analysed data on almost 75,000 post-menopausal American women whose health was tracked for around 12 years.
The women were weighed and measured several times during the study – and also provided their measurements from when they were 18, 35 and 50 years old.
Some 40 per cent of the women had always been slim.
This left 60 per cent who had been overweight at some point in their lives – and almost half of these had been obese.
Some 6,300 of the women were diagnosed with cancer. And the longer they had been overweight, the higher their odds of the disease.
The figures for endometrial cancer, which affects the lining of the womb, were particularly striking. The odds of the disease rose by 17 per cent, on average, for every decade a woman was overweight.
But for a severely obese woman, the risk increased by 37 per cent. BMI is a measurement of weight related to height. Below 25 is healthy, between 25 and 29.9 overweight, and 30-plus obese.
A 5ft 3in woman who weighs 9 stone, has healthy BMI of 22.3. But at 11 stone, her BMI is 27.3 and she is overweight.
If her weight creeps up to 12 and a half stone, her BMI goes into the obese range at 31. At 14 stone, she would have a BMI of 35 and classed as severely obese.
It is thought hormones released by fat in the body feed tumours. The immune system may also release harmful chemicals and DNA may be damaged more, raising the odds of cancer. Writing in the journal PLOS Medicine, Dr Arnold said it is important that women are aware of the link.
She said: ‘If we can prevent overweight and obesity from early on and promote maintaining a healthy weight, this would probably be a good strategy to reduce the prevalence of overweight and increase health.’
Fiona Osgun, of charity Cancer Research UK, said: 'This study is a good start, but it’s difficult to unpick how changes in a person’s weight over time might affect their cancer risk, so we still need more research to be sure. Obesity is the single biggest preventable cause of cancer after smoking, and is linked to ten different types. This study only studied women but we know from other research that keeping a healthy weight can help reduce men’s risk of the disease too.’