Unhealthy lifestyles are contributing to a rise in cases of cancer around the world, according to new research from the World Cancer Research Fund (WCRF). The analysis evaluated evidence spanning decades and found a link between obesity and 12 different cancers.
WCRF unveiled its Third Expert Report on Thursday at the European Congress on Obesity in Vienna. Led by Imperial College London, researchers assessed all published literature about associations between cancer, physical activity and diet. The studies covered 51 million people, 3.5 million of whom were diagnosed with cancer, making the new report the largest global analysis of cancer causes to date.
WCRF’s second expert report, released ten years ago, found a link between obesity and seven different cancers, but that number has been raised to 12 today. These include cancers of the mouth and throat, stomach, oesophagus, liver, bowel, gallbladder, kidney, pancreas, ovary and womb. Obesity was also linked to advanced prostate cancer and post-menopause breast cancer.
Researchers said that since 2007, the amount of “very strong evidence” connecting cancer to unhealthy lifestyles had increased, leading them to make stricter recommendations in the latest report.
“Avoiding tobacco in any form, together with appropriate diet, nutrition and physical activity, and maintaining a healthy weight, have the potential over time to reduce much of the global burden of cancer,” the report states.
The report recommended reducing time spent on smartphones and computers and fitting in at least 45 minutes of moderate exercise every day – especially for those who have sedentary jobs.
In order to cut cancer risk, WCRF also recommended avoiding all alcohol, processed meats and sugary drinks.
“Our research shows it’s unlikely that specific foods or nutrients are important single factors in causing or protecting against cancer,” said Dr Giota Mitrou, WCRF’s director of research funding and external relations. “Rather, different patterns of diet and physical activity throughout life combine to make you more or less susceptible to cancer.”
Experts welcomed the findings, but said the occasional unhealthy snack would not cause serious harm.
“A bacon butty or glass of wine every so often isn’t anything to worry about, it’s the things you do every day that matter most,” said prevention expert Professor Linda Bauld of Cancer Research UK. “Building small changes into your daily life, like choosing sugar-free drinks or walking more, can add up to a big difference for your health.”
The report warned that if current trends continue, being obese or overweight is expected to surpass smoking as the top risk factor for cancer.
Cancer currently causes around one in six deaths worldwide, a figure that is projected to increase, according to the report. By 2035, new cases of cancer are expected to reach 24 million globally – a 58% increase. Although home to only an eighth of the world’s population, Europe accounts for a quarter of global cancer cases with around 3.7 million new patients each year.