THURSDAY, Feb. 3 (HealthDay News) -- Although blacks make up only 13.6 percent of the U.S. population, they account for 50.3 percent of all diagnosed cases of HIV, federal health officials reported Thursday.

The rate of HIV diagnosis among black men is eight times that of whites, and the rate for black women is 19 times that of whites, finds a new analysis of data from 37 states by the U.S. Centers for Disease Control and Prevention.

"What this study confirms is the severe and disproportionate burden of disease borne by African Americans when it comes to HIV," said Dr. Kevin Fenton, director of CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention.

Compared to Hispanic men, black men have twice the rate of HIV infection, and black women are four times as likely as Hispanic women to have an HIV diagnosis, according to the Feb. 4 edition of the CDC's Morbidity and Mortality Weekly Report.

The reasons for these disparities are complex, Fenton said. "We are not looking at one core issue. There are many factors interacting with each other at different levels within the society," he said.

For one thing, the background prevalence of the AIDS-causing virus is higher in the black community, he said.

"This higher background prevalence really continues to drive transmission within the community, because it increases the probability of someone coming into contact with HIV, even with low-risk behaviors," Fenton said.

Sharing drug materials and having unprotected sex are key ways to spread HIV.

Fenton said there is also a higher rate of sexually transmitted diseases in the black community, noting other STDs facilitate the transmission of HIV.

Disparities in access to health care and poverty also contribute to the increased risk of HIV among blacks, Fenton explained.

High rates of male imprisonment are another factor, he added. "This leads to imbalances in male-to-female ratios in the community, which in turn result in sexual networks which facilitate transmission of HIV," he said.

In a related report in the same edition, researchers said HIV diagnoses have skyrocketed among young black gay men in Milwaukee, Wis. Among 15- to 29-year-old black gay men in that city, HIV increased 144 percent from 2000 to 2008.

William Jeffries IV, a CDC Epidemic Intelligence Service Officer and co-author of the report, said this spike is not just the result of increased HIV screening, which would by itself uncover many new cases of HIV.

The number of syphilis cases also increased, which suggests a rise in HIV infection, Jeffries said.

The Milwaukee findings probably mirror similar HIV increases in some areas across the country, said the researchers, calling for new or better efforts to educate this group of males.

The CDC already is testing ways to expand HIV testing and referral services within the black community, Jeffries said.

These "intensive behavioral interventions," he said, combine education, counseling, skills development and esteem building, as well as safer sex promotion.

Apathy about HIV is a problem, Fenton said. "We are really grappling with increased complacency as we enter the fourth decade of this epidemic," he said. This is particularly true in the black community, where there are so many health and economic concerns that HIV becomes a back-burner issue, Fenton said.

Commenting on the report, Dr. Michael Kolber, professor and director of the Comprehensive AIDS Program at the University of Miami Miller School of Medicine, said that programs to reduce the spread of HIV need to target those communities where transmission rates are highest and take into account various cultural differences.

"In the African American community, we are working with faith-based organizations," he said. "They really play a major role in daily living."

The programs Kolber runs go into churches and provide HIV/AIDS education in the context of overall health issues.

"When you discuss these things, you need to do it in a manner which is sensitive to what they are willing to listen to," Kolber said.

More information

For more information on HIV/AIDS, visit the U.S. Department of Health and Human Services.