New cancer rates among men fell 0.6% annually from 1994 to 2008, among women they dropped 0.5% yearly from 1998 to 2006, and among children rose from 1992 to 2008, according to the Annual Report to the Nation on the Status of Cancer, which was published in the journal Cancer. From 2004 to 2008, average cancer death rates for both sexes dropped by 1.6% annually.

The authors show how the impact of two lifestyle factors – overweight and physical inactivity – impact on the risk of developing several different types of cancer.

Below are some of the findings published in the report:

  • Men, 1994-2008. New cancer cases dropped by 0.6% annually
  • Women, 1998-2006. New cancer cases fell by 0.5% yearly

  • Women, 2006-2008. New cancer rates remained unchanged
  • Children, 2004-2008. Death rates dropped 1.3% per year, but new case rates rose by 0.6%

Highest rates of new cancer diagnoses were among Caucasian women and African-American men between 2004 and 2008. The death rate (from cancer) was highest among African-American men and African-American women from 2004 to the end of 2008 – however, rates in both groups fell the most from 1999 to 2008.

A number of risk factors, as well as access to treatment and screening impacted on the differences in cancer deaths and incidence rates, the authors wrote.

Lung cancer – the death rate from lung cancer has fallen among adult females for the second year in a row. For men, the fall has continued steadily since the beginning of the 1990s. The authors say the fall is due to effective anti-tobacco programs carried out by individual states.

The death rates from lung cancer started to fall among men much earlier than women, because women started smoking in large numbers much later than men did.

Colon cancer – thanks to colon cancer screening, both death rates and new case rates continue to fall.

Breast cancer – from 1999 to the end of 2004, the rate of new cases fell steadily, and then remained the same until the end of 2008.

Other cancers – from 1999 to the end of 2008, the new case rates of the following cancers rose – liver, thyroid, pancreas, kidney, and a type of esophageal cancer. The authors say physical inactivity and overweight were major factors impacting on these incidences.

This annual report includes a special features section, which in 2013 concentrates on the impact of body weight and physical inactivity on cancer risk.

Smoking tobacco has been the major factor influencing cancer risk for over three decades. Since the 1960s, the prevalence of regular tobacco smoking has dropped by one third, while the percentage of the total population who are obese has more than doubled. Physical inactivity not only raises the risk of developing cancer, but also heart disease, hypertension, arthritis, and diabetes.

John R. Seffrin, Ph.D., chief executive officer of the American Cancer Society:

“In the United States, 2 in 3 adults are overweight or obese and fewer than half get enough physical activity. Between children and youth, 1 in 3 is overweight or obese, and fewer than 1 in 4 high school students get recommended levels of physical activity. Obesity and physical inactivity are critical problems facing all states. For people who do not smoke, excess weight and lack of sufficient physical activity may be among the most important risk factors for cancer.”

The authors say that for non-smokers, maintaining a healthy body weight over the long term is one of the most important things they can do to reduce cancer risk. For a smoker, giving up smoking is still the most important thing to do.

Obesity affects the immune system, hormones and results in more inflammation, all drivers of cancer risk. Adults should make sure they do at least 150 minutes of moderate exercise (physical activity) each week, or 75 minutes of vigorous exercise.

Written by Christian Nordqvist