SINGAPORE: Obesity is more likely the cause in some types of cancer than smoking, according to the findings of a study released by a cancer research organisation on Wednesday (Jul 3).
According to Cancer Research UK, four common cancers – bowel, kidney, ovarian and liver – are more likely to have been caused by being overweight than by smoking tobacco.
Excess weight causes around 1,900 more cases of bowel cancer than smoking in the UK each year, the organisation said. The same pattern is true of kidney cancer (1,400 more cases), ovarian cancer (460 more cases) and liver cancer (180 more cases), it said.
Besides these four cancers, nine other types of cancer have also been linked to obesity, said Cancer Research UK. These are breast, pancreatic, oesophageal, upper stomach, gallbladder, womb, thyroid, blood and brain cancers.
"Scientists have so far identified that obesity causes 13 types of cancer but the mechanisms aren’t fully understood. So further research is needed to find out more about the ways extra body fat can lead to cancer," said Cancer Research UK chief executive Michelle Mitchell.
People who are obese now outnumber smokers two to one in the United Kingdom, according to the study. There are 14.9 million obese adults in the UK, about one-third of the country's adult population.
Cancer Research UK said being overweight or obese increases the chance of cancerous cells being made.
“Extra body fat sends out a signal that can tell cells to divide more often and, similar to smoking, can cause damage that builds up over time and raises the risk of cancer.”
The organisation has launched a campaign in the UK to increase awareness of obesity-cancer risk, but its advertisement featuring cigarette packaging with the phrase "Obesity is a cause of cancer too" has been criticised for fat-shaming.
Previous campaigns against obesity by Cancer Research UK have been similarly criticised for likening obesity to smoking.
Last year, comedian and campaigner Sofie Hagen took to Twitter to criticise the campaign and demanded that its advertisements be pulled.
In response, Cancer Research UK said that the campaign “isn’t meant to make anyone feel bad” about being overweight but aims to “raise awareness of the link between cancer and obesity”.
Other than the four cancers highlighted, smoking remains the UK's leading preventable cause of cancer, it said on Wednesday.
The organisation urged the UK government to tackle childhood obesity. It suggested reducing the number of junk food advertisements on TV and online, and restricting promotional offers on unhealthy food and drinks.
More than one in five children in the UK are overweight or obese before they start primary school, it said.
Professor Linda Bauld, Cancer Research UK’s prevention expert, said: "There isn’t a silver bullet to reduce obesity, but the huge fall in smoking over the years – partly thanks to advertising and environmental bans – shows that government-led change works. It was needed to tackle sky-high smoking rates, and now the same is true for obesity.
"The world we live in doesn’t make it easy to be healthy and we need government action to fix that, but people can also make changes themselves; small things like swapping junk.”
Britain’s sugar tax on soft drinks came into force on April last year in an effort to tackle obesity.