Other studies have found that being poor is bad for your health, but the new research is one of the first to include actual measures of household income.

Previous work has relied largely on indirect measures of income, such as education levels or the median income of particular ZIP codes.

The study findings were somewhat unexpected because the people in the study should have received equal medical treatment. Researchers from Duke University Medical Center analyzed data from people who had enrolled in a clinical trial of a drug to prevent blood clots. Everyone in the trial was supposed to get the same medical care. As volunteers enrolled, they reported their annual incomes.

Last week, during a meeting of the American College of Cardiology, the researchers reported that patients with the lowest incomes - less than $10,000 annually - had a higher death rate at six months, more than twice as high as the patients with higher incomes. The study's authors believe that the poorest patients, who tend to be elderly, may not be able to afford their prescription drugs once they leave the hospital, or may return to situations with little social support.

-Laura Beil

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One in four young women showed early signs of heart disease in a study released last week in Atlanta at the annual meeting of the American College of Cardiology.

Researchers from Cincinnati Children's Hospital Medical Center performed echocardiograms, which are ultrasound exams of the heart, on 575 generally healthy women, average age 19.

The tests looked for an increase in heart mass or a thickening of the wall in the left ventricle, the main pumping chamber of the heart.

Twenty-five percent of the women showed signs of the heart malformations, which the researchers linked to obesity.

''These results suggest that preventive efforts should be aimed at weight control,'' said Dr. Tom Kimball, senior author of the study and director of echocardiography at the medical center. ''Echocardiography should be considered a screening tool in obese adolescent and young adult women to identify those at risk for cardiovascular diseases.''

-Sherry Jacobson

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Some brands of an herbal treatment commonly used for mild to moderate depression may not contain enough active ingredients, a new study has found.

Researchers at the University of Southern California conducted chemical tests on eight commercial brands of St. John's wort, measuring two key types of ingredients - hyperforin and hypericins.

Only two of the tested brands contained levels of hyperforin shown to be effective in treating depression, the scientists wrote. Hyperforin is not typically measured to gauge the potency of St. John's wort products; however, it appears to affect how the herb interacts with other drugs.

In addition, one of the eight products fell far short of its label claim about its hypericin content. Hypericins are the active ingredient listed on most labels of St. John's wort products.

The study, which appears this month in the American Journal of Health-System Pharmacy, recommends that manufacturers measure hyperforin as well as hypericins to standardize St. John's wort treatments.