Obesity could be playing a role in rising rates of bowel cancer in women under 50, a new study suggests.
Bowel cancer is still rare in this age group, but cases among UK women aged 25-44 have increased by 73% over the past 20 years, according to Cancer Research UK.
Researchers in the US found that obesity was linked to a higher risk of developing bowel cancer in women younger than 50.
The study, which used data from a large group of US nurses, mainly included white women so the findings need to be confirmed in other ethnicities and among men.
Cancer Research UK’s Katie Patrick said the results served as a reminder that keeping a healthy weight is important at any age.
The study, published in JAMA Oncology by researchers at Washington University School of Medicine in St Louis, Missouri, followed 85,256 women over an average of 14 years, using body mass index (BMI) as an indicator of obesity.
BMI works out if you have a healthy weight for your height. People with a BMI of 25 or over are classified as overweight, and those with a BMI of 30 or over are classified as obese.
There were 114 cases of early onset bowel cancer among the women in the study, and obesity – as judged by a BMI over 30 – was linked to a higher risk of developing the disease.
A higher BMI at the age of 18 and weight gain of more than 40 kg since early adulthood were also both linked to an increased risk of early onset bowel cancer.
Keeping a healthy weight
Patrick said that while bowel cancer cases remain uncommon among younger people, more still needs to be done to help reduce bowel cancer risk at any age.
She said: “Bowel cancer in younger people is still rare, with around 630 women aged 25-44 diagnosed in the UK each year.
“As well as keeping a healthy weight, there are lots of other ways to reduce bowel cancer risk, such as not smoking, eating plenty of foods high in fibre and cutting down on alcohol and processed and red meat.
“Keeping a healthy weight helps to reduce cancer risk for adults at any age, which is why it’s vital that the Government acts to help make healthy choices easier for everyone.”
Liu, P-H., et al. (2018) Association of Obesity With Risk of Early-Onset Colorectal Cancer Among Women. JAMA Oncology. DOI: 10.1001/jamaoncol.2018.4280