In an international study, by the University of Bergen, Norway, researchers found that the risk of cancer is increased by being overweight.
The researchers wanted to find out how overweight adults (with a BMI over 25) and obesity (with a BMI over 30) increase the risk of cancer – here the study found that if individuals were overweight before the age of 40, then the risk of developing different types of cancer increases by an alarming rate.
Developing the risk of cancer
The study showed that if you were overweight before age 40, the risk of developing cancer increases by the following:
- 70% for endometrial cancer;
- 58% for male renal-cell cancer;
- 29% for male colon cancer and
- 15% for all obesity-related cancers (both sexes).
Professor Tone Bjørge, at Department of Global Public Health and Primary Care, University of Bergen, explains: “Obesity is an established risk factor for several cancers. In this study, we have focused on the degree, timing and duration of overweight and obesity in relation to cancer risk.”
This is further supported by a previous study that looked at the share of cancers related to obesity, finding that excess body weight is an established cause of cancer.
Obesity increases risk over time
In the study, the researchers included adults with two or more measurements, obtained at least three years apart, and before a possible cancer diagnosis. On average, the individuals were followed for about 18 years.
Obese participants (BMI over 30) at the first and second health examination had the highest risk of developing obesity-related cancer, compared to participants with normal BMI.
“The risk increased by 64% for male participants and 48% for females,” Bjørge says.
Avoiding the gain of unhealthy weight
Obesity is a global challenge and associated with increased risk of several types of cancer. The results from the study show that overweight and obese adults have an increased risk of postmenopausal breast, endometrial, renal-cell and colon cancer
“Our key message is that preventing weight gain may be an important public health strategy to reduce the cancer risk,” concludes Bjørge.