Obesity: rising fears of cancer time bomb

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James Meikle, health correspondent8 January 2004Cancers linked to people being overweight are showing significant increases, suggesting that the clock on the obesity time-bomb might be running more quickly than feared.

New diagnoses during the second half of the 1990s suggest that cancers of the prostate, womb, kidney, breast, bowel and pancreas all became more common.

They showed increases above the overall 5.8% five-year rise to Britain's all-time annual high for new cancer cases, 270,425 in 2000.

But these may be just an early signs of what is to come since rising obesity has only become a major worry to governments in the last decade while cancers take years to develop and are mainly diseases of people over 50. Already as many as one in eight non-smoking related cancer deaths might be linked to obesity and that is likely to get worse.

Fewer than 30% of adult men are now thought to have the body mass desirable for best health prospects and more than one in five is obese, a rise of two-thirds in a decade. More than one in five women are also obese, up 40% since 1993, while obesity rates in children are soaring too.

The shifting pattern of cancers was revealed yesterday by Cancer Research UK, using figures compiled by cancer registries. Some related to heavy drinking also revealed big increases, reflecting another of the public health menaces facing ministers. And the tendency of Britons to go mad in the sun, without sufficient protection, is reflected in the steady rise in melanomas, up nearly 24% in five years to 6,967 new cases.

Dr John Toy, medical director of Cancer Research UK, said: "It would be wrong to suggest on the evidence available that all of these rises were down to obesity. But even should obesity not be the sole factor, it is a factor which is controllable within people's lifestyles should they choose to do it. There is not any reason for people to stuff themselves on burgers and make themselves fat." People could also control their behaviour in the sun, he added.

Measures to slow, halt and then reverse the staggering rises in obesity in recent years are only now being hammered out - with rows over the contribution of advertising aimed at children, diminishing school sports fields, fast food outlets and salty, sugary, fat-laden ready meals and snacks.

Howard Stoate, chairman of the all-party parliamentary group on obesity, recently described the health threat from obesity as more serious than that posed by smoking.

The government is also expected soon to launch a long-awaited strategy to stem the tide of alcohol-induced illness and death.

The new cancer figures do suggest positive results from the battle against smoking. There are fewer new lung cancer cases, down 5.3% over five years to 38,410, although the tendency of young women to smoke and passive smoking continue to be big worries.

New cases of cancer in Scotland have fallen 4% overall over three years up to 2000, the only part of Britain to show a decrease, and the main reason is a big decrease in men's lung cancers there.

Excessive weight is a risk factor in several cancers, although some diseases are still at relatively low levels in terms of absolute numbers. The exact reason for the association is not always clear but changes in sex hormones are thought important with fatty tissues providing extra breeding grounds for cancer cells.

Breast cancer, where excessive weight is a factor once women pass the menopause, recently overtook lung cancer as the most common form. But in the 1999-2000 period, the figures dropped for the first time in years, by 600 to 40,707. Scientists will be anxious to know if this was a blip since numbers were still up more than 12% on 1995.

Regular heavy drinking is thought to increase women's breast cancer risk slightly but there is still much debate over whether smoking plays a part.

Obesity is a risk factor in bowel cancer, up over five years by 6.1% to 35,300 in 2000. Excessive weight is also thought to be linked to more advanced stages of prostate cancer in men, although the main reason for a 25.4% rise to 27,149 cases is increased detection, through the PSA blood test, of cancers that will not be life threatening.

Kidney cancers are up 15.3% to 6,199, those of the pancreas up 5.9% to 7,090 and of the uterus up 22% to 5,624.

Oesophagal and liver cancers show big rises, possibly linked to alcohol. More hepatitis infections and obesity may be linked to the liver increase.

Screening seems to have brought big decreases in cervical cancer, down 13% to 2,991, with early detection and treatment of pre-cancerous conditions being important factors.

http://society.guardian.co.uk/publichealth/story/0,11098,1118252,00.html