The importance of regular exercise and a healthy diet to maintain a healthy weight should not be underestimated. Healthy habits often need to be fostered. They need to be automatic and practiced consistently. The earlier they are developed, the bigger the benefits. My youngest daughter, Elaine, moved into a college dorm this past week. There were a lot of parents concerned about the meals and weight gain. They may not have realized that it is not just about physical appearance but also about long-term health. I am reasonably sure Elaine will make good choices about eating, and the snacks she has requested for her room include fresh fruits and vegetables and whole grain cereals. She plans to swim, so hopefully she will get a lot of exercise and maintain a healthy weight.

Body-mass index (BMI) is a simple and commonly used measurement which is a ratio of weight and height. Normal BMI is 18.5 to 24.9 kg/m². Adults with a BMI of 25–29.9 kg/m² are considered overweight, and adults with a BMI of 30 kg/m² or higher are considered obese.

The ever-growing obesity epidemic has sparked research into the effects of an increased BMI on cancer risk both in the United States and globally. Surprisingly, until recently, most research on associations between BMI and increased cancer risk have been primarily from observational studies and meta-analyses. Many of the studies have had inadequate statistical power and other limitations that prevent definitive conclusions and extrapolation.

It appears that increasing body size has significant associations with 10 common types of cancer, in a recent study of more than 5.2 million British individuals. The study reported that 41% of uterine and 10% or more of gallbladder, kidney, liver, and colon cancers could be attributable to excess weight.

The results showed that every 5.5 kg (about 11 lb)/m² increase in BMI was associated with increases in the risk for the following cancers.

  • Cervical cancer
  • Colon cancer
  • Gallbladder cancer
  • Kidney cancer
  • Leukemia
  • Liver cancer
  • Ovarian cancer
  • Postmenopausal breast cancer
  • Thyroid cancer
  • Uterine cancer

After tobacco, obesity is probably the single most important cause of cancer that can be prevented. This study provides the strongest evidence to date that increasing BMI is associated with increased risk of cancer for a number of cancers. Even small increases in BMI are associated with increased cancer risk. The study suggests that direct efforts to help populations keep BMI in an acceptable range by exercising regularly and making healthy food choices are important and an effective means of true primary cancer prevention. 

The study provides strong evidence that policy changes aimed at the number of overweight and obese individuals are needed. In 2012, the World Health Organization issued policy recommendations, and recommendations have also been issued by the Centers for Disease Control and Prevention. Some of the policy strategies are designed to help individuals maintain ideal BMI by decreasing caloric intake and increasing physical activity. Examples include taxes on calorically dense, nutritionally sparse foods such as sugar-sweetened beverages and subsidies for healthier foods, especially in economically disadvantaged groups, and increasing sidewalks and bike paths to promote exercise and physical activity.

As nurses, we often tell people that physical activity and eating healthy are important measures to promote health. This study provides evidence that such habits can reduce the risk of multiple types of cancer.

Watch for more information about the ONS Get Up, Get Moving campaign this fall.