A new United Nations study shows more people today are aware of the fatal disease AIDS, but behavior remains risky. Surveys were conducted in more than three dozen developing countries in Asia, Africa and Latin America.

The study found that the level of awareness of AIDS is higher among men than among women, and this awareness grows in proportion to the incidence of HIV/AIDS in individual countries. The study also points to a difference between urban and rural areas, with people in rural areas less aware of the AIDS threat.

Perhaps the more disturbing bit of data for health workers is that many people, even though they are aware of the HIV/AIDS epidemic, do not perceive a great risk in contracting the infection.

Joseph Chamie, an official with the U.N. Population Division, which complied the AIDS data, says there is some evidence that people are indeed changing their behavior to avoid the disease but not enough to make a huge difference:

"We need more research on how we can effectively change behavior," Mr. Chamie said, "We need to inform people about the risks and that their risks are not insignificant. And in addition, there have to be clear messages on what can be done and where to go, especially when we are talking about issues like mother-to-child transmission, and also treatment."

Surveys have shown regional differences in HIV infections. For example, experts note a relatively low incidence of AIDS among the conservative Muslim populations of northern Africa and the Middle East, where there are strong taboos about sexual behavior. HIV/AIDS is more prevalent in central and sub-Saharan Africa, with infection rates in southern Africa thought to be about 30 times higher than in the north. In many African countries, surveys show most men are still not willing to use condoms to prevent infection.

The study was released one year after the U.N. General Assembly held a special session on HIV/AIDS, aimed at persuading governments to put the issue at the top of their agenda. The United Nations estimates about 40 million people worldwide have HIV, the virus that causes AIDS.