Monday, April 23, 2007

Ladies, Run - or Walk - for Your Life

Talking about people in the public eye, like Elizabeth Edwards, who have breast cancer can raise our own anxiety level. Naturally we ask ourselves “How can I dodge this bullet?” Except for non-lethal skin cancers, breast cancer is the type most often diagnosed in women. Unfortunately, scientists still don’t know what causes breast cancer most of the time. Even when a risk factor has been proven, it is likely to be beyond our control. For example, beginning menstruation early is linked with future breast cancer -- but do any of use choose when to begin menstruating?

Instead of feeling powerless, women are asking "how can our daughters choose?" Somehow, across the US girls start menstruating earlier and earlier. Can we reverse that? How? Is it in the water? Your genes have to interract with aspects of their environment for cancer to start, whether you control those environmental conditions or not. However, Americans generally prefer to focus their attention on personally modifiable risk factors, e.g. behaviors that we can each change as individuals.

See You at Curves?
Smiles of relief greeted Dr Leslie Bernstein at a public meeting in Marin County, CA in January when she said individuals willing and able to exercise will be rewarded with some level of breast cancer protection. Bernstein, of the University of Southern California, has been studying the potential cancer risk reduction of physical activity since the 1980s.

A prescription for an aerobics class is of course an oversimplification even if it's grounded in research. To benefit, women should get at least three hours of activity per week and keep their weight down. Further, it appears that exercise benefits young women most, probably by reducing their exposure to their own reproductive hormones. But older women may get results, too – particularly if they develop the exercise habit while young. A recently published study based on Bernstein’s work strongly suggests that a long term habit of strenuous exercise can reduce the risk of breast cancer by half. Even moderate exercise such as walking significantly reduced breast cancer in the 111,000 California teachers Bernstein studied.

As research progresses on risk factors, we are learning about complicated contingencies vital to cancer biology. To understand why exercise lowers cancer risk involves endocrinology, reproductive biology, immunology and other disciplines within medicine. And in order to explore the interactions between the lifestyle choices, environmental toxins and our cells that lead to cancer, one needs to add elements of toxicology -- so that’s another column (or two!).

More Girl Scout Hikes, Fewer Girl Scout Cookies
Regaining some control over our lives confers strength on women whether or not we have breast cancer or daughters to worry about. We can take personal steps, but if a reduction in breast cancer depends on starting young and continuing to be active, we should consider the public health implications of funding for physical education, parks and recreation programs, bikes paths, etc. We can also advocate for additional research into publicly modifiable risk factors such as environmental contamination. Let’s do everything we can to be among the 88 percent of American women who never develops breast cancer – and to help other women avoid it, too.

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