About 300 million people worldwide are believed to be obese and a further 750 million overweight, a physical state increasingly associated with an elevated risk of life-threatening conditions, notably heart disease and diabetes.
"We found that the risk for getting AML was 90 per cent higher in overweight women age 55 and older who had a body mass index [BMI - the measure of body fat based on height and weight] of 25-29," says Julie Ross, associate professor of paediatrics at the University of Minnesota medical school.
While the scientists were unable to explain the association between a higher BMI and leukaemia, particularly AML, they propose a "possible explanation could be an alteration in hormones linked with obesity."
Opportunities to tackle the low-fat, low-sugar food markets have picked up in pace for the food industry that has been singled out by consumer groups as a key player in the obesity epidemic of today.
And potential gains are considerable, spurred on by health-conscious consumers seeking to moderate sugar and caloric intake without sacrificing taste and texture. Demand for artificial sweeteners and fat replacers in the US alone is slated to grow to $1.2 billion (€0.9bn) in 2004 with fat replacers growing over seven per cent annually, estimate market analysts Freedonia.
And in September this year industry giants such as Heinz, Coca-Cola and Cadbury Trebor Bassett signed a seven step manifesto that kicks off in 2005 to cut portion size, a move to help tackle the epidemic. In addition, the €99.58 billion food and drink industry said that labelling, advertising, salt reduction and vending machines in schools will all figure in the seven point plan.
"FDF's food and health manifesto sets out the UK food and drink manufacturing industry's commitment to work constructively with consumers, government and others to help find solutions to the complex, multi-factorial issues surrounding obesity and the food and health debate generally," said John Sunderland, president of the Food and Drink Federation, the industry body behind the manifesto.
While research has suggested that overweight and obesity are risk factors for colon, breast, kidney and endometrial cancers the recent study on more than 37,000 older American women carried out by the University of Minnesota Cancer Center examined the potential link between obesity and the risk of leukaemia.
AML, a cancer that starts in the bone marrow, is the most common acute leukaemia with about 11,900 patients diagnosed annually, 90 per cent of them adults aged 65 and older, estimates the American Cancer Society.
Over 14 years 200 of the women developed leukaemia - 74 were diagnosed with AML and 88 with chronic lymphocytic leukemia (CLL). All were cancer-free at the beginning of the study.
"In obese women age 55 and older and with a BMI of 30 or greater, the risk of getting AML increased to as much as 140 per cent," said lead researcher Julie Ross.
Ross added that a limitation of her study was that only postmenopausal, mostly white, women participated. She also says that BMI was calculated using weight and height reported by each participant, which could be subject to some degree of imprecision. But BMI is the standard for population-based studies.
Full results of the study are published in the November issue of the journal Cancer Epidemiology, Biomarkers and Prevention journal.