Ricardo Uauy, a professor of Public Health Nutrition at the London School of Hygiene and Tropical Medicine, was the lead member of the international panel of independent experts who worked on the report that found obesity linked to higher ovarian cancer risk.
The report, published jointly by the World Cancer Research Fund International and the American Institute of Cancer Research, is a comprehensive analysis of all the global scientific research on the link among weight, diet, physical activity and ovarian cancer.
It is the first time that ovarian cancer was directly linked to any lifestyle factor, Uauy said.
Body fat increases the risk for ovarian and other cancers in complex ways. Fat tissue is not only the main energy store in our bodies, but it is also metabolically active, producing hormone like compounds that promote inflammation and specific proteins that can affect cell growth and turnover, thus increasing the risk of some forms of cancer, Uauy explained.
"This finding is significant for two reasons. Firstly, ovarian cancer is both difficult to detect and often deadly, with the chances of the cancer recurring quite high. Secondly, maintaining a healthy body weight offers women a way to reduce the risk of getting the disease," Uauy said on his blog at World Cancer Research Fund International.
"This should not be interpreted to mean that excess weight is the single most important risk factor for ovarian cancer. The fact is that if you're a woman with a family history of ovarian or breast cancer, are taller than most women or smoke, your risk for breast cancer is increased."
However maintaining a healthy weight represents an important new addition to preventive strategies against ovarian cancer, he added.
The panel analyzed all relevant studies that investigated ovarian cancer's link to diet, physical activity and weight. There were 25 studies related to weight, involving 4 million women.
The report concluded every five increments of body mass index increased women's risk of ovarian cancer by 6 percent.
For example, for two women both 5 feet, 5 inches, tall with all other factors equal, the woman weighing 200 pounds would be at 6 percent higher risk of developing ovarian cancer than her counterpart at 170 pounds.