Obesity affects colon cancer risk differently in women and men, new research reveals.

British researchers analyzed data from more than 58,000 people with colon cancer and nearly 68,000 without.

The takeaway: A higher body mass index (BMI, an estimate of body fat based on height and weight) is more dangerous for men, while a higher waist-to-hip ratio (a measure of abdominal fat) is more dangerous for women.

A BMI of 25 and over is considered overweight, while a BMI of 30 or more is considered obese. In the study, an increase in BMI of about 5 points was associated with a 23% higher risk of colon cancer for men, compared to 9% for women.

An equivalent increase in waist-to-hip ratio increased women's risk by 25%, and men's by only 5%, according the researchers.

"Our study, which is the largest to look at the difference between body fat and colorectal cancer risk in men and women, reveals the need for a more nuanced approach when trying to prevent cancer," said study co-leader Emma Vincent, a researcher in the School of Cellular and Molecular Medicine at the University of Bristol.

In a university news release, she said researchers are now working to understand exactly how increased body fat causes colon cancer, which may provide new targets for reducing risk.

"It's well-established that keeping a healthy weight affects many types of cancer," said Natasha Paton, health information manager of Cancer Research UK. "Most research linking excess weight to cancer uses BMI, but this study adds to the evidence that carrying excess fat around the waist is also important."

She said people can reduce their colon cancer risk by maintaining a healthy weight, eating a diet with lots of fiber and less red and processed meats. Drinking less alcohol and not smoking are also important, Paton added.

Early diagnosis is critical, so tell a doctor if your bowel habits change and take advantage of screening, she suggested.

The study was published Dec. 16 in the journal BMC Medicine.