A major new study that uses a simple blood test to identify which patients can best be protected from heart disease by taking statins, the cholesterol-lowering drugs, is being heralded by doctors as a stunning prevention breakthrough, but it's particularly good news for women.

While statistics make it clear that heart disease is the leading killer of women, doctors have not been able to agree on whether statins shield women as well as they do men from heart disease and death. "This issue had gotten quite contentious, because there was not evidence to prove statins' effectiveness in women," says Dr. C. Noel Bairey Merz, director of the Women's Heart Center at Cedars-Sinai Medical Center. While there have been a number of major studies looking at statins' effectiveness in men, she says, "no one had bothered to conduct a (quality, large-scale clinical trial) that enrolled enough women to adequately answer the question."

Researchers' decision not to include women in clinical trials has been a problem for decades. Traditionally, researchers preferred to enroll only men because they considered their physiology less complex —they don't have monthly cycles, they don't get pregnant and they don't go through menopause. The doctors just assumed that what worked for men would surely work for women. Some researchers also "had this mindset that only men have heart disease," adds Dr. Nieca Goldberg, a clinical associate professor at New York University who specializes in heart disease in women.

Yet as it became clearer that there were significant gender differences in medicine—women and men often exhibit different symptoms and respond differently to treatments in heart disease as well as other disorders—doctors became more cautious about extrapolating results from studies of men to develop treatment for women. So even as statins became a popular prevention method for men, doctors tended to use them less aggressively for women.

But the results of the Jupiter study, which enrolled nearly 18,000 men and women from 26 countries, and was released at a meeting of the American Heart Association on Nov. 9, could change all that. The massive study found that giving statins to people whose blood tests showed increased levels of inflammation helped cut their risk of cardiovascular disease in half, even if their cholesterol levels were normal. And, adds Merz, it worked as well for women as it did for men. "This is the first time we have documented evidence that women get the same benefits from statins as men for primary prevention," Merz says.

The Jupiter study also increases the evidence that inflammation is an independent marker of increased risk of heart attacks and strokes. Doctors have long known that people with high cholesterol levels have more heart attacks than those who don't. But they were puzzled by evidence that most people who have heart attacks "were not those considered to be at high risk," Merz says. That seemed to signal to researchers that they were missing something. The simple blood test used in the Jupiter study—the C-reactive protein (HSCRP) test—measures a substance called C-reactive protein, which detects levels of inflammation. "It's equally nice that this is not an expensive tool (it costs about $20), compared to CT scans or stress tests," says Merz. "This is a simple, nonfasting blood test."

What action should women take as a result of these new findings? "I think all women over 60 (this is the age when women's heart-disease risk pulls even with men's, and the age of the women enrolled in the Jupiter study) who are not already on statins should call their doctor and ask what's the most productive way of using this new study," says Goldberg. Many patients with no heart disease and low cholesterol levels who were not candidates for HSCRP under the old guidelines, may find their doctors are recommending it now, she says.

As result, says Goldberg, "I expect that this will now be part of a complete risk analysis, even for healthy women over 60 who are coming in to have their heart-disease risk evaluated," says Goldberg. If their HSCRP test indicates inflammation, their doctor may well suggest they start statins. While the Jupiter study used only the statin Crestor, and its manufacturer, AstraZeneca, helped fund it, researchers said the company was not involved in the analysis of the results. While it has not been proven that other statins would work as well as Crestor, which is particularly potent, most doctors assume that all statins would produce similar, if possibly more modest, results. "This preventative treatment is relatively efficient and economical, since a majority of the statins are available as generics," Merz says. "You can go to Costco and for five bucks, you can save your life."