Major New American Cancer Society Study Links Obesity to Increased Cancer Death Risk

American Cancer Society
Wednesday, 30 April 2003

Heaviest Americans Have 50 Percent to 60 Percent Higher Risk

In the biggest study of its kind to date, American Cancer Society researchers say current patterns of overweight and obesity in the United States could account for 14 percent of all cancer deaths in men and 20 percent of those in women. The report documents an association between body-mass index (BMI) and death from most forms of cancer, and concludes 90,000 cancer deaths a year are related to weight.

The study, published in the April 24, 2003 issue of the New England Journal of Medicine, identifies several forms of cancer not previously linked widely to unhealthy body weight, including stomach (in men), liver, pancreas, prostate, non-Hodgkin lymphoma, multiple myeloma, cervix, and ovary. The report also substantiates previous studies linking overweight and obesity to cancers of the colon and rectum, breast (in postmenopausal women), uterus, kidney, esophagus, and gallbladder.

"Many Americans have not acknowledged the contribution of obesity to chronic disease in general and to cancer in particular," said Eugenia E. Calle, PhD, director of analytic epidemiology for the Society and the article's lead author. "For example, women are very concerned about breast cancer, but few understand that obesity doubles their risk of getting and dying from the disease."

"This study shows nutrition and physical activity are critical pieces of the cancer puzzle," said Harmon J. Eyre, MD, national chief medical officer for the Society. "But they're often overlooked. Our survey in 2002 found only one percent of Americans identified maintaining a healthy weight as a way to reduce cancer risk."

The prospective study of more than 900,000 U.S. adults (404,576 men and 495,477 women) who were free of cancer at enrollment in 1982 identified 57,145 deaths from cancer during 16 years of follow-up. American Cancer Society researchers examined the relationship between BMI (a measure of body fat based on height and weight) and subsequent risk of death from all cancers and from cancer at individual sites, while controlling for other risk factors, like smoking. Researchers calculated the proportion of all deaths from cancer attributable to overweight and obesity in the U.S. population on the basis of risk estimates from the current study and national estimates of the prevalence of overweight and obesity in the U.S. adult population.

The findings in the study are consistent with American Cancer Society guidelines to maintain a healthful weight throughout life by balancing caloric intake with physical activity and losing weight if you are currently overweight or obese. [The American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention can be viewed at: http://caonline.amcancersoc.org.

"Our results are based on data on mortality and reflect the combined influence of body-mass index both on the incidence of cancer and on survival, whereas most of the available literature on site-specific cancers is based on incidence data," said Dr. Calle. The research was conducted by Dr. Calle, Carmen Rodriguez, MD, MPH, Kimberly Walker-Thurmond, BA, and Michael J.Thun, MD.

For more information, or to contact American Cancer Society, see their website at: www.cancer.org