FRIDAY, June 24, 2011 (HealthDay News) -- Lifestyle changes such as losing weight, drinking less alcohol and getting more exercise could lead to a substantial reduction in breast cancer cases across an entire population, according to a new model that estimates the impact of these modifiable risk factors.
Although such models are often used to estimate breast cancer risk, they are usually based on things that women can't change, such as a family history of breast cancer. Up to now, there have been few models based on ways women could reduce their risk through changes in their lifestyle.
U.S. National Cancer Institute researchers created the model using data from an Italian study that included more than 5,000 women. The model included three modifiable risk factors (alcohol consumption, physical activity and body mass index) and five risk factors that are difficult or impossible to modify (family history, education, job activity, reproductive characteristics, and biopsy history).
Benchmarks for some lifestyle factors included getting at least 2 hours of exercise a week (for women 30-39) and having a body mass index (BMI) under 25 (in women 50 and older).
The model predicted that improvements in modifiable risk factors would result in a 1.6 percent reduction in the average 20-year absolute risk in a general population of women aged 65; a 3.2 percent reduction among women with a positive family history of breast cancer; and a 4.1 percent reduction among women with the most non-modifiable risk factors.
The authors pointed out that the predicted changes in lifestyle to achieve these goals -- such as former and current drinkers becoming non-drinkers -- might be overly optimistic.
But, the findings may help in designing programs meant to encourage women to make lifestyle changes, according to the researchers. For example, a 1.6 percent absolute risk reduction in a general population of one million women amounts to 16,000 fewer cases of cancer.
The study appears online June 24 in the Journal of the National Cancer Institute, where the author of an accompanying editorial applauded the research.
The findings provide "extremely important information relevant to counseling women on how much risk reduction they can expect by changing behaviors, and also highlights the basic public health concept that small changes in individual risk can translate into a meaningful reduction in disease in a large population," Dr. Kathy J. Helzlsouer, of Mercy Medical Center in Baltimore, wrote in a journal news release.
The U.S. National Cancer Institute has more about breast cancer risk.