New findings from a Cancer Research UK-funded study indicate that 5% of all cancers (around 6,000 cases) in middle-aged and older women are caused by obesity or being overweight.

The Million Women Study – the biggest ever undertaken to assess cancer risk in females  -looked at over one million women in the UK over even years, during which time there were over 45,000 cases of cancer and 17,000 related deaths.

The study, results of which were published in the British Medical Journal online yesterday, backed previous evidence of a link between obesity and cancer, but also revealed that the degree of risk from being overweight varies with different types of cancer.

Womb cancer and a certain type of oesophageal cancer come top of the list, with obesity causing half of all cases, but it is also a major risk factor for kidney cancer, leukaemia, multiple myeloma, pancreatic cancer,non-Hodgkin's lymphoma, ovarian cancer and, in some age-groups, breast and bowel cancer.

Furthermore, the research found that the relationship between weight and cancer also varies if the woman has gone through the menopause or not. For example, a high body mass index boosts the risk of breast cancer only after the menopause, while the chance of developing bowel cancer is higher before it, the charity explained.

Commenting on the results of the study, Sara Hiom, director of Cancer Research UK's health information, said: “While most people readily associate carrying extra weight with being a general health risk, many do not make a specific link with cancer.” She stressed that the findings “need to betaken into consideration alongside the established strong relationships between body fatness and other common illnesses such as diabetes and heart attacks.”

Stronger evidence

And Dr Colin Waine, Chair of the National Obesity Foundation,told PharmaTimes UK News that, although the link between obesity and cancer has been known about for some time, the report has strengthened the evidence onw hich this occurs. “This is a very important report,” he stressed. “We musn’t loose cancer from the equation of diseases linked to obesity.”

When asked whether he thought enough is being done to drive home the dangers of being obese to the public, he said that the risks are pretty well portrayed, “but what we are not achieving is getting people to do something about it.”

A recent report warned that Britain has become a nation where being overweight is the norm, and stressed that urgent action is needed to reign in the bulging incidence of obesity, which could cost the economy a breath-taking £45 billion by 2050.

The hard-hitting findings by Foresight’s project Tackling Obesities: Future Choices predict that, by 2050, 60% of adult men, 50% of adult women and about 25% of all children under 16 could be obese, presenting a huge healthcare challenge and underscoring the need to address the issue now.