Obesity could cause four in ten cases of cancer, according to a groundbreaking study.
The major role it plays in the deadly disease is even greater than feared, according to research among 4.1 million adults.
Experts say obesity is now linked to more than 30 types of cancer – up from the 13 known to play a role.
They warned that the ‘groundbreaking’ research, which spanned four decades, shows the country is facing a devastating time bomb.
The study found that every five point increase in body mass index (BMI) (which is equivalent to gaining about three stone for someone at a healthy weight) increases the risk of developing several common cancers by 24 percent in men and by 12 percent in women.
Your browser does not support iframes.
Your browser does not support iframes.
The same increase was linked to 19 other cancers, increasing the risk by 17 percent for men and 13 percent for women.
Health organizations said it should serve as a ‘wake-up call’ for ministers and called for restrictions on junk food advertising to tackle Britain’s obesity epidemic.
Katharine Jenner, director of the Obesity Health Alliance, said: ‘The results are clear: if we can prevent obesity, we can prevent many types of diet-related cancers.
‘This should be a wake-up call for the UK government(s) around the world to urgently implement public health policies that will make a meaningful difference, such as restrictions on the marketing of junk food and levies on unhealthy food.
‘We must ensure that the healthy choice becomes the easy choice for everyone.’
Your browser does not support iframes.
Scientists believe that obesity may increase the risk of cancer through biological mechanisms such as chronic inflammation, changes in metabolism and changes in hormone levels.
Decreased participation in cancer screening programs and reduced effectiveness of screening procedures in people with obesity may also be factors.
The study, led by Lund University in Malmö, Sweden, involved 4.1 million people who monitored their weight and lifestyle for about 40 years.
Some 332,500 cases of cancer were diagnosed during this period, and of these, in 40 percent of cases, there was a link between obesity and cancer.
Researchers examined 122 types and subtypes of cancer in a study that followed patients over a follow-up period of more than 100 million years.
In total, researchers have identified 32 types of cancer linked to obesity, more than double the 13 types of cancer identified by the International Agency for Research on Cancer in 2016.
The new research, which will be presented at the European Congress on Obesity in Venice, confirms that these cancers – including breast, colon, uterine and kidney cancer – can be caused by obesity.
For the first time, a further 19 potential obesity-related cancers were also identified, including malignant melanoma, stomach tumours, cancers of the small intestine and pituitary gland, as well as types of head and neck, vulvar and penile cancer.
According to the research, around four in 10 cancer cases could be caused by obesity.
Lead researcher Dr Ming Sun said: ‘Our findings suggest that the impact of obesity on cancer could be greater than previously known, as it is a risk factor for more types of cancer, especially the rarer ones.
‘Some of these have rarely or never been studied before in relation to obesity.’
She added: ‘Implementing public health measures that enable and advocate healthy lifestyles are essential to tackling the obesity epidemic and its already known detrimental effect on health outcomes.’
According to the latest NHS England health survey, 26 percent of adults are obese and a further 38 percent are overweight, costing around £6.5 billion a year.
Dr. Jennifer Baker, co-chair of the European Association for the Study of Obesity’s Childhood Obesity Working Group, said that with 60 percent of adults in Europe either obese or living with pre-obesity, “we are likely to see a significant increase of the number of cancer cases.
One million patients, who were of a healthy weight and a body mass index (BMI) of 18 to 25, would cost the NHS an average of £638 per person in 2019, the final year of the study. By comparison, severely obese patients with a BMI of 40 and above cost more than double: £1,375 per year. Meanwhile, the NHS spent £979 a year on obese patients with a BMI of 30 to 35, rising to £1,178 a year for those with a BMI of 35-40
Describing it as a ‘groundbreaking study’, she said: ‘Researchers show obesity is associated with 19 new cancers, some of which are surprising, in addition to the 13 already identified.
‘As we are likely to underestimate the burden of cancer due to obesity, these results show that more attention should be paid to obesity in cancer prevention programmes.’
Professor Jason Halford, chairman of the European Association for the Study of Obesity, said: ‘This is a really strong large-scale analysis.
‘As always, more research is needed, but it shows what many who study the links between cancer and obesity have suspected; that obesity is likely a risk factor for many more types of cancer than we previously had evidence for.
“If this doesn’t raise concerns among health care policymakers, it’s hard to see what will.”
The Health Secretary said the Key Conditions Strategy will set out the Government’s approach to tackling lifestyle factors that cause ill health and disease, such as diet and obesity, and highlighted successes such as the sugar reduction programme.
Victoria Atkins said: ‘I want us all to be able to live longer, healthier lives. This starts with preventing diseases through healthy lifestyle choices, such as eating well, exercising regularly and not smoking.
‘We are already introducing world-leading legislation to protect future generations from the harms of smoking to reduce diseases such as cancer, and we are also taking strong action to tackle obesity.
‘By investing in technology like the NHS Couch to 5k app we’re helping families across the country get fit and active, and I’m excited about the new treatments and technologies that can help people achieve (and maintain) a healthy weight ).’