Let's get moving!

Good afternoon to all.   As promised, I am now blogging about breast cancer prevention.  We have made great strides against breast cancer, from treatment to early detection; but another opportunity avails us, that of prevention.  We will discuss the many steps that can be taken to reduce the numbers of breast cancers by beginning with physical activity and exercise.

There have been numerous studies reported that show a negative correlation between exercise and breast cancer development, which means: more movement equals fewer breast cancers.  Let's examine just three.  An extensive review of the literature in 2008 (Br J Sports Med 2008;42:636-647) found evidence for risk of breast cancer reduction with increased physical activity in the majority of studies, with an average reduction of 25-30%.  Stronger reductions were noted for lifetime or later in life activity.  Never too late to start moving!  The second review comes form the Nurses' Health Study (Arch Intern Med 2010:170:1758-1764 or online www.channing.harvard.edu/nhs/) which reports on 95,396 women in 20 years of follow-up.  During this period, there were 4782 breast cancers.  Women who were the most active (>1 hour per day walking) or those who increased activity at menopause were at the lowest risk.  Likewise, the Women's Health Initiative Cohort (JAMA 2003;290:1331-1336) demonstrated fewer breast cancers with increasing exercise among 74,171 postmenopausal women followed 5 years.  10 hours or more per week of "brisk walking" led to the lowest breast cancer rate.

We know that 75% of breast cancers occur in postmenopausal women, so how does exercise reduce the number of breast cancers in these women.  The answer is not entirely clear, but research suggests an effect on decreasing endogenous estrogen, decreasing inflammatory factors that may lead to breast cancer, increasing immunity (two other studies show fewer colds and flu-like illnesses in exercisers) or all of the above.

So the best you can do: get moving!  The worst thing: don't move!  An American Cancer Society study (Am J Epidemiol July 2010 online) compared people who spent at least 6 hours a day of their leisure time sitting to those who sat less than 3 hours a day.  The data from 69,776 US women 50-74 years old was astounding!  The increase in the death rate for the least active women was 94% or almost double!  So, LET'S GET MOVING!!