WASHINGTON (AFP) - About 40 per cent of all cancers in the United States - more than 630,000 in all - are associated with excess weight, health officials said on Tuesday (Oct 3), urging a renewed focus on prevention.
In a nation where 71 per cent of adults are either overweight or obese, the findings by the US Centres for Disease Control and Prevention "are a cause for concern," said the agency's director Brenda Fitzgerald.
"A majority of American adults weigh more than recommended - and being overweight or obese puts people at higher risk for a number of cancers," she said in a statement.
"By getting to and keeping a healthy weight, we all can play a role in cancer prevention."
Carrying excess weight has been shown to boost the risk of 13 types of tumours, including cancers of the oesophagus, thyroid, post-menopausal breast, gallbladder, stomach, liver, pancreas, kidney, ovaries, uterus, colon and rectum.
The rates of these overweight- and obesity-related cancers are rising, in contrast to the overall rate of new cancer cases which has dropped since the 1990s.
Colorectal cancer was the only weight-associated cancer that decreased from 2005-2014 - falling 23 per cent, due in large part to screening, said the report.
All other cancers linked to weight rose 7 per cent in that decade.
About two-thirds of the 630,000 weight-associated cancers diagnosed in 2014 occurred in people aged 50 to 74.
Women were particularly susceptible, with 55 per cent of all cancers diagnosed in women associated with weight, compared to 24 per cent of those diagnosed in men.
According to the latest CDC data, 32.8 per cent of people in the United States are overweight, and 37.9 per cent are obese.
Being overweight is defined as having a body mass index of 25-29.9 kg/m2, while obesity means a BMI of 30 or above.
BMI is calculated by taking a person's weight in kilograms divided by the square of the person's height in metres.