Being Overweight Increases Risk of Breast Cancer

Overall, cancer death rates are on the decline, but obesity is a growing cause of cancer in the US.

Overall, death rates from cancer have decreased in the US, but excessive weight and lack of physical activity have become major causes of cancer. Graph courtesy of the CDC.

Here’s the good news: Death rates from all cancers for men, women, and children declined from 2004 to 2008.

And here’s the bad news: Excess weight and lack of exercise have become common causes of cancer in the US, even though they are completely avoidable, according to the Annual Report to the Nation on the Status of Cancer.

The report, coauthored by the Centers for Disease Control (CDC) and various national cancer organizations, found that incidence rates increased for certain cancers associated with being overweight and lack of physical activity. In the past 30 years, tobacco use has been the leading cause of cancer in the US. However, while tobacco use has declined by a third, obesity rates have skyrocketed, doubling since the 1960s, according to the report. In particular, overweight or obese post-menopausal women were more likely to be diagnosed with breast cancer, the report read.

The findings resemble a study presented at the European Breast Cancer Conference last week. The study found that overweight or obese women who had breast cancer were at higher risk of getting cancer again.

What’s particularly notable about the results is that chemotherapy dosage was adjusted for body weight during the study. The results from both reports suggest that lifestyle factors, not just treatment factors, can influence cancer prognosis.

The annual report reviewed more than 7,000 studies that linked other cancer types to excess weight and insufficient exercise. Incident rates for kidney cancer increased by 4.1 percent for men and 3.3 percent for women each year from 2004 to 2008. Pancreatic cancer incidence rates also increased by about 1.2 percent each year, as did uterine cancer and adenocarcinoma of the esophagus.

“This report demonstrates the value of cancer registry data in identifying the links among physical inactivity, obesity, and cancer,” said CDC director Thomas R. Frieden in a statement.

The report recommends that people follow the 2010 Dietary Guidelines for Americans in order to prevent cancer. The guidelines say children ages 6 to 17 years old should do at least 60 minutes of physical activity per day, while adults should get at least 150 minutes of moderate-intensity or 75 minutes of vigorous exercise every week.

For more information on the report, click here