TUESDAY, July 13 (HealthDay News) -- A couple-focused program cut risky sexual behaviors among black American couples in which one partner has HIV and the other is HIV-free, researchers report.

Researchers assigned 260 "serodiscordant" (differing in HIV status) black couples to a program that included eight weekly two-hour sessions that dealt with communication, problem-solving and other interpersonal factors associated with sexual risk reduction.

Another 275 serodiscordant black couples were assigned to a comparison group that took part in a program to increase fruit and vegetable consumption, physical activity and adherence to medical treatments, including HIV therapy.

At six and 12 months after the programs, the couples in the sexual risk-reduction program reported more consistent use of condoms than those in the comparison group (63 percent vs. 48 percent) and reported an average of 1.5 fewer acts of unprotected intercourse.

At the 12-month follow-up, there was no difference between the two groups in the cumulative incidence of sexually transmitted diseases, however. Of the partners who were HIV-free at the start of the study, two in the intervention group and three in the comparison group became HIV-positive during the study.

The study, published online July 12 in advance of print publication in the Sept. 27 issue of the Archives of Internal Medicine, will be presented at the upcoming International AIDS Conference in Vienna, Austria.

The rate of new HIV infections is about seven times higher among black Americans than among whites. Blacks made up about 12 percent of the U.S. population in 2006, but accounted for 45 percent of new HIV infections that year. Heterosexual exposure was the most common source of HIV infection among black women and the second most common source among black men.

"Public health scientists have urged a shift beyond individual-level HIV interventions to prevention strategies that have an impact on social structures and context to curb the epidemic among African Americans," wrote Nabila El-Bassel, of Columbia University School of Social Work, New York City, and colleagues.

"The intervention used here, in structure and content, was relationship based and redirected the focus to changing the relationship factors that influence sexual decision making and increasing the likelihood that risk reduction will be stable over time," she said.

More information

The U.S. Centers for Disease Control and Prevention has more about HIV transmission.