Cancer risk from obesity differs for men and women

A new study, led by researchers at the University of Bristol and the International Agency for Research on Cancer (IARC), has revealed that where fat is on our body may lead to different health outcomes for men and women. The research, co-funded by World Cancer Research Fund (WCRF), Cancer Research UK and Diabetes UK, found that having more body fat around your waist is more dangerous for women than it is for men when it comes to risk of developing colorectal cancer (also known as bowel cancer). This large study, published in BMC Medicine today [17 December], included over 100,000* people. They found that a higher BMI (body mass index; a measure of total fat) is more dangerous for men, whereas a higher waist-to-hip ratio (your waist circumference divided by your hip circumference; a measure of abdominal fat) is more dangerous for women. To discover this, they used an approach, called Mendelian randomisation, that uses genetic information as a proxy measure for weight to investigate the effect of different body fat measures on colorectal cancer risk in men and women. An increase in BMI of about five kg/m² raised the risk of colorectal cancer by 23 per cent for men, but only nine per cent for women. Whereas an equivalent increase in waist-to-hip ratio raised the risk for women by 25 per cent, this was only five per cent for men.