Could Where I Live Raise My Risk of Breast Cancer?

My fellow blogger Sean Kelley recently wrote about how fat his home state is. (He lives in Alabama, second fattest state in the nation, according to stats from the Centers for Disease Control and Prevention.) One of Sean’s points was that it’s no surprise that fat Alabama also has a high incidence of diabetes. There is a proven obesity-diabetes link.

That got me thinking about a disease that weighs more heavily on my mind. Could where I live (Tennessee) affect my risk of getting breast cancer? And how does a person figure out how healthy her state is, anyway?

Turns out that the CDC also tracks disease incidence and mortality by state. The most recent info is from 2004, and it’s fascinating, particularly because it’s in the form of a map (who doesn’t love a map?). I was relieved (briefly) when I found that Tennessee is pretty low when it comes to incidence of breast cancer. But when I scroll down to the mortality map, it isn’t good news. Strangely, even though BC incidence is relatively low, mortality rates are high. Other states, like Oregon, have high incidence rates and lower mortality rates. So why does one state have higher rates of breast cancer than another and why are people more likely to die of it in some states?

There is no simple answer. Even an expert at the National Cancer Institute admits it’s challenging to separate the individual lifestyle and reproductive factors that we know contribute to breast cancer—obesity (find out how fat your state is here), alcohol consumption (find out how much alcohol your state consumes here), the onset of puberty and menopause, not having a child or having a first baby after 30—from the environmental factors (pollution or pesticide use, for example) in each state.

“It’s complicated,” agrees Marisa. C. Weiss, MD, president and founder of Breastcancer.org and director of breast radiation oncology at Lankenau Hospital in Philadelphia.

When there are clusters of high breast cancer numbers it can look like an environmental issue when it’s not. “There can be areas of states with dense populations, like Long Island in New York, where there is a high incidence of breast cancer. But it’s because there are a great deal of older people or double-income-no-kids couples there. Or San Francisco, where there’s a population of lesbians who haven’t had children,” Dr. Weiss says. Those high state numbers don’t mean the risk is higher for you, the individual.

The availability of BC screening and treatment, as well as the ethnic and racial mix of a state can impact the mortality numbers. For instance, there’s a 14 percent disparity in cancer survival rates between whites and blacks in the United States, according to the Concord study done by a team in Great Britain and published in The Lancet Oncology. The disparity is most likely due to differences in the stage of cancer when it’s diagnosed, researchers say. In addition, “African-American women do tend to get breast cancer earlier and get a more virulent form of the disease,” says Dr. Weiss. States with higher numbers of black women with breast cancer may have higher mortality rates.

Those factors that affect breast cancer incidence and mortality don’t really make one state more “cancerous” than another. Sure there may be more women with higher risks there, but last I heard (thank God), breast cancer isn’t catching. So maybe where you live doesn’t matter?

Not so fast. Genetic predisposition, reproductive activity, and lifestyle factors are only part of the equation. The Breast Cancer Fund’s 2008 State of the Evidence examines “the increasingly sophisticated and compelling data linking radiation and myriad chemicals in our environment to the current high rates of breast cancer.” We’re talking everything from air pollution to pesticides to secondhand smoke. In fact, a recent survey done by the Silent Spring Institute (a nonprofit research organization) indicated that 216 chemicals and radiation sources “have been recognized by national and international regulatory agencies as being implicated in breast cancer causation.”

Is your state industrial? Polluted? Your risks may be higher, says Julia Brody, PhD, executive director of Silent Spring, which has used a geographic information system (GIS) to map air and water pollutants in the Cape Cod area, where breast cancer rates are 20 percent higher than the rest of Massachusetts. When the usual suspects can’t be blamed for cancer hot spots like this, Brody says, environmental factors—septic systems that leak into drinking water, cranberry bogs that have been sprayed with pesticides—start to get more attention. Her research has shown connections between both of those factors and local breast cancer rates.

Getting a picture of your own state’s environmental issues and their possible link to breast cancer risk is tricky. Sure, you can check the air quality in your area at EPA’s AirData site, water quality here, and the location and cleanup of hazardous waste sites here. But scientists are still trying to link all of that to breast cancer incidence. And breast cancer doesn’t just turn up overnight, points out Robert A., Hiatt, the director of population science and deputy director of the University of California San Francisco Comprehensive Cancer Center. “It may take 20 to 40 years to be diagnosed in one state after some initiating event in earlier life in another state.”

Maybe that means I should be more worried about where I grew up (Wisconsin) or lived before I had children (New York) than where I live now. A 2005 study in western New York, for instance, linked exposure to polycyclic aromatic hydrocarbons (PAHs) at the time of birth to an increased risk of postmenopausal breast cancer decades later. (PAHs are products of incineration found in air pollution, like vehicle exhaust, tobacco, and smoke.) And breast cancer rates are five times higher in women exposed to the synthetic pesticide DDT in girlhood, says Brody. I wonder, was Wisconsin spraying toxic stuff when I was growing up? Although Silent Spring has mapped pesticide use in parts of Massachusetts, I’m having trouble finding my exposure based on where I’ve lived. Let me know if you find a source.

In the meantime, I’m working hard not to let my breast cancer fears run away with me. I’d love to pack my bags and head to some imagined safe harbor (Montana looks good: It’s a very clean state, according to pollution watchdog Scorecard.org, and I’m sure if I bumped into sometime resident Dennis Quaid, my health would be vastly improved), but I better focus closer to home. Even fresh-aired Montana (and handsome Dennis) can’t change the fact that I had my children after age 30 and that I need to lose some weight (both proven BC risk factors). So I’m focusing on what I can control (like making sure I get my yearly mammogram), eating better, and exercising. My state may have some scary statistics, but that doesn’t mean I have to become one of them.

(PHOTO: GETTY IMAGES)