New study shows that fitness trumps fatness in determining risk of cancer death in men
The Cooper Institute

Cancer is the second leading cause of death among U.S. men. While tobacco use and poor diet remain the largest contributors to cancer mortality, there is growing evidence that obesity and low levels of cardiorespiratory fitness may contribute to cancer mortality as well. A new study from The Cooper Institute recently published in Obesity reports the relation between cardiorespiratory fitness levels, different measures of body fatness, and cancer mortality in men.

Lead researcher and director of professional education Steve Farrell, Ph.D., studied 38,410 men who completed a comprehensive baseline physical examination at Cooper Clinic in Dallas. "This study shows that sedentary individuals of all body fatness levels should strive to become at least moderately fit in order to decrease their risk of cancer mortality," said Farrell.

Results showed a strong and direct relationship between all measures of body fatness and cancer mortality. Leaner men had significantly lower rates of cancer mortality than fatter men, regardless of the method used to assess body fatness. A strong inverse relationship between cardiorespiratory fitness level and cancer mortality was also observed, showing lower-fit men had significantly greater rates of cancer mortality than higher-fit men.

The examination included a maximal treadmill exercise test, which provides an objective measure of cardiorespiratory fitness level. A unique feature of the study was that different measures of body fatness including body mass index (BMI), percent body fat, and waist circumference were also performed. The men were followed for an average period of 17.2 years, during which 1,037 cancer deaths occurred.

Another unique feature of the study was an examination of the cancer mortality rates between fit and unfit men within various categories of the different measures of adiposity or fat levels. Using the three official categories for BMI (normal weight, overweight, obese), fit men in each category had significantly lower death rates from cancer than unfit men. Using the two official categories for waist circumference (obese and non-obese), fit men in each category had significantly lower death rates from cancer than unfit men. Similarly, using two categories for percent body fat (obese and non-obese), fit men in each category also had significantly lower death rates from cancer than unfit men.

Dr. Farrell added, "These data suggest that attaining a moderate to high level of cardiorespiratory fitness may decrease some of the cancer mortality risks associated with increased adiposity."