Women who have the AIDS virus die faster than men with the infection, a study found, and the reasons may be social rather than medical.

The study tracked 768 women and 3,779 men - all HIV-positive - for about 15 months. The women were 33 percent more likely to die than men who were comparably ill when they enrolled in the study.No medical reason for the difference was apparent. The women didn't seem to get sicker any faster than the men, they just died sooner, said researchers led by Sandra L. Melnick, an epidemiologist at the University of Minnesota School of Public Health.

In women twice as often as in men, death was the first sign that HIV was progressing, the researchers found. In men, the first signs of the infection's progress were much more likely to be pneumonia or fungal infections.

That led researchers to speculate that women may wait longer to seek care or may be treated differently by the medical system.

Women represent only about 15 percent of U.S. AIDS cases, but women and children are the fastest-growing group of people with AIDS, a co-author of the study, Dr. Renslow Sherer, said in today's issue of The Journal of the American Medical Association.

"We're still way behind in reaching women at risk nationally," said Sherer, director of the Cook County HIV Primary Care Center in Chicago.

Dr. Alexandra Levine, chief of hematology at the University of Southern California School of Medicine and a researcher on HIV in women, said her own findings suggest nonmedical factors play an important role in how infected women fare.

"It is extremely common for a woman to say she wants an HIV test but was afraid to ask the doctor," Levine said in a telephone interview. "When she does ask, he says, `No, you don't need one, you're a nice girl.' Then, she has to say, `No, I'm not a nice girl.' "