Over 124,000 cancers caused by excess body weight in Europe last year
At least 124,000 new cases of cancer in Europe last year may have been caused by excess body weight, experts have claimed.
Scientists from the UK, The Netherlands and Switzerland created a statistical model that enabled them to estimate the proportion of cancers that might have been due to excess body weight.
They used their model to calculate estimates for 30 European countries, using data from the World Health Organisation, the International Agency for Research on Cancer and other sources.
Out of nearly 2.2 million new cancer diagnoses across the 30 countries in 2002, over 70,000 appear to have been attributable to excess body weight, defined as a body mass index (BMI) higher than 25.
Proportions of cancer cases that were attributable to a high BMI varied between countries.
For instance, just 2.1 per cent of cancers in Danish women and 2.4 per cent in Danish men are thought to have been due to excess body weight, compared with four per cent of cancers in British women and 3.4 per cent in British men.
Moving their focus to 2008 figures, the researchers estimated that 124,050 cancers could be attributed to excess body weight, including 3.2 per cent of cases in men and 8.6 per cent in women.
Nearly three quarters (65 per cent) of cancers attributable to excess BMI were womb cancers (33,421), postmenopausal breast cancers (27,770) and bowel cancers (23,730).
Lead author Dr Andrew Renehan, from the University of Manchester, who presented the findings at the European cancer congress ECCO 15 - ESMO 34 in Berlin this week, commented: "As more people stop smoking and fewer women take hormone replacement therapy, it is possible that obesity may become the biggest attributable cause of cancer in women within the next decade.
"I must emphasise that we are trying not to be sensationalist about this. These are very conservative estimates, and it's quite likely that the numbers are, in fact, higher."
The researchers noticed that the UK has a particularly high incidence of obesity-related oesophageal cancers compared with other European nations.
Dr Renehan revealed that the UK accounts for 54 per cent of new cases across all 30 countries involved in the study.
"This may be due to synergistic interactions between smoking, alcohol, excess body weight and acid reflux - and is currently an area where research is required," he added.
The scientist also provided an explanation for the recent increase in breast and womb cancers that can be attributed to obesity, pointing to the dramatic drop in hormone replacement therapy (HRT) use in 2002.
He explained: "In women who used HRT it wasn't clear what proportions of breast cancers were caused by HRT or by obesity. In women who don't take HRT, the effect of obesity was much clearer.
"Now that far fewer women are using HRT, it is much easier to see the effect of obesity on the incidence of breast cancer, and also on endometrial cancer. Consequently, the proportions of these cancers attributable to obesity have increased."
Dr Renehan also noted that the findings underline the importance of tackling the obesity epidemic in Europe.
He claimed: "In the face of an unabating obesity epidemic and apparent failure of public health policies to control weight gain, there is a need to look at alternative strategies, including pharmacological approaches."
Henry Scowcroft, Cancer Research UK's science information manager, said: "Although the numbers differ from other similar analyses, this is a good, strong study which confirms that obesity is an important avoidable cause of cancer.
"These results provide important and sobering projections for the present and future impact of obesity on European cancer rates."