Mya Nelson
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A new report we’ve released today suggests that staying a healthy weight may offer women a relatively modest — but significant — protection against ovarian cancer, one of the most deadly cancers for women.
The findings of AICR/WCRF’s latest Continuous Update Project report, Food, Nutrition, Physical Activity and the Prevention of Ovarian Cancer, means that ovarian cancer now joins the list of cancers linked to obesity. Research now shows that excess body fat links to increased risk of eight cancers, including postmenopausal breast, colorectal and pancreatic.
For the report, scientists analyzed all relevant studies that investigated ovarian cancer’s link to diet, physical activity and weight. There were 25 studies related to weight, including four million women.
The report concluded that every five increments of BMI increased women’s risk 6 percent. That risk started on the high end of overweight, towards the obesity category, which starts at a BMI of 30. That means 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.
That risk is relatively small compared to how obesity increases risk for colorectal or endometrial cancers, for example. And factors such as each woman’s age or family history places women at a different risk to start.
But obesity is a risk factor that women can change. And after not smoking, being a healthy weight is one of the most important ways that both women and men can prevent cancer, along with many other chronic diseases.
For symptoms and other risk factors for ovarian cancer, you can read more on the Centers for Disease Control and Prevention site. BMI is one measure of body fat (it’s not perfect, as Alice wrote about here); visit our BMI page to calculate yours.
I hate to be picky, but isn’t more accurate to say that obesity has been linked to ovarian cancer as opposed to saying that obesity causes ovarian cancer? Your infographic states that excess body fat causes cancer. I haven’t seen any studies, nor am I sure how you would produce such studies, that show obesity is the cause of the cancer. Isn’t it much more likely that the causes of obesity and the causes of many forms of cancer are so closely linked that there is a strong correlation. I agree that encouraging people to maintain a healthy body weight through healthy diet and exercise will reduce the occurrence of cancer, but I am unconvinced that obesity itself is a cause of cancer. Do you have some evidence I am missing?
Good question. I asked AICR Director of Research Susan Higginbotham, PhD, RD, and here’s what she said:
While no evidence is ever perfect and causation is not going to be proven conclusively, the expert panel on our reports uses carefully formulated criteria to infer causal relationships. The criteria take into account study design and methods as well as agreement among studies. Good quality studies adjust for other factors that play a role in cancer risk, such as physical activity, and the panel takes this into account. In order for the panel to judge a factor such as obesity or body fatness a ‘probable’ or ‘convincing’ cause of cancer, there must be credible evidence of biologic pathways that are in play. For the obesity-cancer link, the expert panel found that the body of evidence met the criteria to be judged a ‘probable’ cause. Probable means the evidence is compelling enough to use to make recommendations for cancer prevention, and we would conclude it is a cause. There are many other possible causes, but obesity is a factor in at least some of these cases.