Harvard Medical School researchers set hearts atwitter at the annual American Heart Association meeting in New Orleans last weekend when they announced a major study verifying the health benefits of taking cholesterol-lowering statins even for people with normal levels of cholesterol.

In the study, published in the New England Journal of Medicine, almost 18,000 men and women were given either a statin or a placebo and then followed for nearly two years in a study called Jupiter—Justification for the Use of Statins in Prevention: An International Trial Evaluating Rosuvastatin. (The trade name for rosuvastatin is Crestor, made under license in the U.S. by AstraZeneca.)

Impressively, the statin-popping group was 44 percent less likely to have a heart attack than the placebo group, and 21 percent less likely to die from heart disease. The test was so successful that an independent review board cut short the five-year trial after just two years.

Jupiter was headline news around the world, though there was a piece of the statin story that was missing.

This comes from a second major study published last August, also in the New England Journal of Medicine, that indicates about one in six of all Caucasians carry a genetic variation that could make taking statins risky by increasing the chances of cardiomyopathy. (Asians and Africans have a slightly less risk.)

A potentially dangerous inflammation of the heart muscle, cardiomyopathy is a well-known, but rare potential side effect of statins.

Juxtaposing these two studies provides a glimpse into the future of personalized medicine, when major public health pronouncements like Jupiter will be presented with modifications for subgroups of people according to their genetic profile.

In this case, the genetic study suggests that about 2 percent of those tested have a variation (designated by the genetic letters "CC") that carries a risk nearly 17 times that of people who have the normal variation—an extremely high risk factor for a genetic marker associated with a common disease.

A second variation (designated by "CT") gives a carrier a nearly five-fold higher risk than normal. I carry this CT gene mutation—which is much better than the CC, but is still a higher-than-normal risk.

Both the CC and the CT mutations occur in a gene called SLCO1B1, which helps regulate the uptake of statins and certain other drugs into the liver. People who carry mutations end up with higher-than-normal concentrations of statins in their blood, which can contribute to the onset of cardiomyopathy.

In previous columns, I have described a slew of tests I'm taking for a book called Experimental Man—including a wide range of genetic screens and more traditional tests measuring everything from cholesterol levels to CT scans of my heart and other organs.

The idea of the Experimental Man Project is to report on and assess the many high-tech tests that are about to revolutionize medicine, and to reveal previously hidden secrets about ourselves.

I've taken genetic tests that suggest I am mostly healthy, although I do have a higher-than-average risk profile for a future heart attack. (See my earlier column on this: "I'm Doomed. Or Not.")

I also have borderline high cholesterol and slightly elevated blood pressure—both at levels my physician said warrants attentiveness, but no medication. I have tried to lower my cholesterol through avoiding greasy burgers and exercise, with some success.

However, should I fail in my quest to eat and sweat my way to good health, my physician has told me that I could always take statins. But this was before the New England Journal study and my "CT" test result.

Worried that my fall-back plan might be a bust, I called a key researcher—Rory Collins, professor of medicine and epidemiology at Oxford—for both the Jupiter study and the August paper that revealed my genetic predisposition to cardiomyopathy if I take statins.

On the phone from the heart association in New Orleans, Collins first set me straight about the Jupiter study. The media reported that researchers had shown that people with low cholesterol saw huge benefits from taking statins.

"The news is missing the point," said Collins. "The researchers couldn't test the people they wanted to test, because you can't give people with very high cholesterol a placebo." He said that they set out to prove that lowering so-called "bad" cholesterol (L.D.L. cholesterol) using statins is desirable in everyone.

"But it is much more important to do this in people with high cholesterol, whose risk of heart disease is much greater than someone with low cholesterol."

I asked Collins what role the DNA marker in the SLCO1B1gene might play in deciding whether a person should take statins. He said the variation would not much matter if statins were given in low doses. "That's not a big problem," he said.

For higher doses, however, Collins said that testing for the genetic marker might be a good idea. Testing positive for the highest risk variation could impact the type of statin to be used, he said, and would require more monitoring for myopathy.

He reassured me that my risk factor did not mean I should avoid statins if I ever become a truly high risk for heart attack. "The danger of heart disease outweighs the danger or myopathy," he said.

Would he ever recommend against using a statin based on a person's genetic disposition?

"It depends on the patient's absolute risk," he said. "If they have a high risk of heart attack without the statins, then that needs to be balanced against the possibility of myopathy."

Critics have noted that AstraZeneca, the drug giant that sells Crestor, paid for Jupiter, though numerous independent experts have praised the study. Patients in the Jupiter group also contracted diabetes at a higher-than-average rate, though no one knows why.

The test subjects also tested higher than average for a biomarker called c-reactive protein (C.R.P.) that is present when inflammation is occurring in the body. Sometimes this inflammation is linked to heart disease. Statins lower C.R.P. as well as cholesterol, which have caused some observers to wonder if the wondrous outcomes in the Jupiter trial came from lowering cholesterol, or C.R.P., or both.

Still, scientists in the field are touting Jupiter as a major breakthrough.

What would make it even more impressive is if the scientific community would begin to link up this sort of large-scale study of health trends and treatments with the emerging field of genetic association studies.

In a few cases such as statins, a DNA test might offer a useful piece of information to add to the mix in deciding whether a patient should use a medication, and at what dose.

Currently, few physicians are trained to use genetic tests as part of a diagnosis or as a tool to tailor drugs and other treatments. The reason up until now is that few of these tests are ready to be useful to patients—though this will change as genetic tests are further validated by scientists and physicians.

For me, the knowledge that my liver doesn't properly snatch up statins I happen to swallow will make me try even harder to avoid taking them. And if I do end up taking these pills, I'll know to keep out for any hint that my heart muscle is unhappy.

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For great descriptions and videos from Scripps cardiologist Eric Topol about both Jupiter and the genetic study, go to: http://blogs.theheart.org/topology