Obesity may be linked to more cancers than previously thought, concerning new research has found, and losing weight may be one of the most ‘powerful’ protections against the diseases.
More than 18,000 preventable cancer cases in Britain are currently linked to obesity, making it the second biggest cause of the disease behind smoking.
In England alone, around 28 per cent of adults are obese – classified by the NHS as having a BMI of over 30 – while a further 36 per cent are estimated to have a BMI of more than 25, making them overweight.
Now, fresh findings by research team in Germany have suggested that figures linking obesity to cancer may have been ‘strongly underestimated’.
The research, published in the journal JAMA Oncology, observed data from the UK, Germany and Sweden on the link between the so-called ‘obesity epidemic’ and cancer.
They analysed a study of 458,660 people in the UK Biobank – a resource containing the medical information of volunteers – and found that obesity was linked to 7.2 per cent of gastrointestinal cancers in cases diagnosed in the four years after weight measurement.
However, this rose to 17.7 per cent when cancers diagnosed more than four years later were considered.
This suggests the link between obesity and cancer may be significantly underestimated in Britain, because those with undiagnosed cancer may lose weight.
Obesity may be linked to more cancers than previously thought, new research has found
In Germany, they also studied more than 10,000 people and found that being overweight for many years was more strongly linked to bowel cancer risk than BMI by 55 per cent.
However, they noted that this may not apply to all cancers because different types may respond differently to long-term weight exposure.
In Sweden, their analysis of more than 339,000 people uncovered that men with larger waist sizes had a 25 per cent higher risk of obesity-related cancers, compared with a 19 per cent increase linked to BMI.
This suggests belly fat may be a better predictor of risk than overall weight in men.
Overall, the researchers found that cancer risk begins to rise even below a BMI of 25, meaning current ‘overweight’ thresholds may miss people at risk.
The authors say obesity control has been long ‘underexploited’ as a potential to be a ‘a powerful cancer prevention strategy’ and proposed a new framework named PLUS to better measure risk.
This would account for weight loss before diagnosis, consider lifetime weight, use waist size alongside BMI, and recognise that risk can begin below current thresholds.
They said: ‘The PLUS framework discloses a much stronger cancer-preventive potential of obesity prevention and control than previously established.
‘Given the ongoing obesity epidemic and its links to numerous adverse health outcomes, such as diabetes and cardiovascular disease, this underlines the urgency and expected rewards of enhanced efforts toward prevention and treatment of overweight and obesity.’
The authors also called for actions for obesity prevention to be ‘systematically integrated into public health systems’.
As much of their study was observational, the researchers cannot prove cause and effect.
