WEDNESDAY, July 16 (HealthDay News) -- New research suggests that people of African descent are much more likely to have a genetic trait that makes them more susceptible to infection with the HIV virus.

Scientists estimate that the trait -- which also provides protection against a form of malaria -- might account for 11 percent of the HIV cases in Africa, the continent hardest hit by the AIDS epidemic.

Overall, the finding shows how the past history of evolution and disease still affects people today, said study co-author Matthew J. Dolan, of the Wilford Hall United States Air Force Medical Center and San Antonio Military Medical Center. "The benefit that the Africans got from a mutation that gave them some resistance to malaria has, statistically at least, rendered them some increased susceptibility to HIV," he said.

Researchers have spent years trying to understand why some people who are exposed to the AIDS virus don't get infected. An estimated 70 percent to 90 percent of children born to infected mothers don't develop the disease, and some gay men have avoided it despite repeated exposure.

In the new study, a team of researchers studied more than 1,200 members of the U.S. military who became infected with HIV. They wanted to discover more about how genetics affects the disease.

The findings were published in the July 17 issue of Cell Host & Microbe.

The researchers found that a genetic trait -- found in 60 percent of African-Americans and 90 percent of Africans -- makes HIV infection 40 percent more likely. The trait is virtually nonexistent in whites.

The trait also protects people against a form of malaria that is now uncommon.

It appears that the genetic makeup of some Africans evolved to give them protection against the form of malaria, Dolan said. Unfortunately, the trait ultimately "set up the African continent for increased susceptibility" to HIV, he said.

Dolan estimated that the increased susceptibility could account for millions of extra cases of HIV.

On the other hand, people who have the trait live an average of two years longer with the disease once they get it, the researchers found. "It's a two-edged sword," said study co-author Dr. Sunil K. Ahuja, a professor at the University of Texas Health Science Center in San Antonio.

Rowena Johnston, vice president of research with the Foundation for AIDS Research, said the new finding provides even more evidence of an evolutionary struggle between humans and disease. But it won't be easy to make the information useful.

"Since any one individual has tens of thousands of genes, each of which may influence susceptibility in one direction or another, it's difficult to predict the outcome for any individual with any one particular genotype," she said.

Even if Africans or African-Americans discover they have this particular genetic trait, "What would they do with the information?" she asked.

As for using the new finding to develop a new anti-AIDS drug, that may be difficult because of the limited effect of the genetic trait, she said.

More information

Learn more about HIV and genetics from The Body  .

WEDNESDAY, July 16 (HealthDay News) -- Being born prematurely can lead to a host of long-lasting medical complications and may also affect other areas of life, such as education and income, even when no disability is apparent, a new study suggests.

In the July 17 issue of the New England Journal of Medicine, Norwegian researchers report that babies born prematurely are more likely to have cerebral palsy, mental retardation and to need to receive disability payments.

More surprisingly, the researchers also found that when premature babies grew up, even if they had no identifiable disability, the youngest preemies were less likely to have a high income, more likely to be unemployed, more likely to receive Social Security benefits and less likely to become parents.

"The pessimistic view [of our study] is that we have demonstrated an increased risk for a broad spectrum of medical disabilities due to decreased gestational age, and for those without medical disabilities, a lesser but significant risk for a broad spectrum of social outcomes," said the study's lead author, Dr. Dag Moster, a neonatologist at the Haukeland University Hospital.

On the other hand, said Moster, "The optimistic view is that the majority of preterm survivors in our study do not have medical disabilities and seem to function very well as adults."

The study included data from more than 900,000 infants born without known birth defects between 1967 and 1983 in Norway. Of that group, 1,822 were born between 23 and 27 weeks of gestation -- 40 weeks is considered full-term. Another 2,805 were born between 28 and 30 weeks, while 7,424 were born between 31 and 33 weeks. Slightly less than 33,000 were born between 34 and 36 weeks, and the remainder were born 37 weeks or later.

For those born at term, the risk of cerebral palsy was 0.1 percent, compared to 9.1 percent for those born between 23 and 27 weeks. The risk of mental retardation was 0.4 percent for full-term babies, versus 4.4 percent for babies born between 23 and 27 weeks.

Just 1.7 percent of the full-term group received a disability pension in adulthood, compared to 10.6 percent of those who had been born between 23 and 27 weeks of gestation.

The smallest babies -- those born between 23 and 27 weeks -- who survived with no apparent medical disabilities were also 10 percent less likely to finish high school, 20 percent less likely to have completed college, 20 percent less likely to have a high income, 20 percent more likely to receive Social Security benefits and 20 percent less likely to have become parents than babies born full-term.

There was no association found between premature delivery and unemployment or criminal behavior, according to the study.

"It is important to emphasize that most premature children who survived without medical disabilities completed higher education, had good jobs and appeared to function well as adults," Moster said.

Dr. Jennifer Kloesz, a neonatologist at Children's Hospital of Pittsburgh, said the study's findings point to the need for parents to act as their child's advocate, long term.

"If you have a baby who's made it through the NICU [neonatal intensive care unit] relatively OK, you need to keep reminding your child's health-care team that your child was born prematurely and try to optimize their chances for staying on track with developmental skills. And, be sure to take advantage of whatever services schools offer for premature babies," she said.

More information

To learn more about the immediate health consequences for premature babies, visit the American Academy of Pediatrics  .

FRIDAY, July 11 (HealthDay News) -- Teach parents how to talk about sex with their teen, and they will tackle this tough subject more readily and often, a new study says.

The study, published online July 11 in British Medical Journal, evaluated a workshop-based program called "Talking Parents, Healthy Teens" aimed at parents of 6th- to 10th-graders. In eight weekly, hour-long sessions, the parents use role-playing and other interactive exercises to learned techniques for starting and sustaining conversations on sex in everyday situations. The parents were also instructed on how to listen to their children without interrupting or lecturing, and how to teach decision-making and assertiveness skills to their kids.

The program also recognized diverse views on sex that parent might have. For example, one session covered both abstinence and condom use for teens.

"The great thing was that the parents really learned," lead researcher Dr. Mark A. Schuster, chief of general pediatrics and vice chairman for health policy research at Children's Hospital Boston, said in a news release issued by the hospital. "We'd teach them some skills one week, and they'd come back the next week, bubbling over with excitement that they'd talked with their teen about relationships, love or sex, and this was the best part: Their teen had actually engaged in a real conversation with them, or role-played a topic like how to say no to unwanted sexual advances."

Several surveys done after the program reported the participants said they had more dialogues about sex with their kids than ever before and were also better able to discuss sex openly with their children.

Similar follow-ups with the participant's children agreed. For example, they reported in a survey done one week after the classes concluded that 18 percent of their parents had gone over how to use a condom, compared with 3 percent of the parents in a control group. Nine months after the sessions ended, this gap had grown to 25 percent versus 5 percent.

The researchers held the program sessions during lunch breaks at large private and public companies, a strategy designed to draw more parents to the program through convenience alone.

"Many employers provide programs to help employees lose weight or stop smoking," Schuster said. "We wanted to see if we could apply worksite health promotion principles to help parents address their kids' sexual health. It turned out that employers loved the idea. They are under pressure to create family-friendly workplaces. And they're often providing the health insurance for these kids, so they are concerned about lost productivity when parents are distracted with their kids' sexual health issues."

More information

The U.S. Department of Health & Human Services has more about talking to your child about sex.

THURSDAY, July 10 ( HealthDay News) -- A new study questions whether vaginal microbicides being developed to help protect women against HIV infection could lead to new drug resistance from the virus that causes AIDS.

The study, published July 7 in the online issue of Proceedings of the National Academy of Sciences, also shows that, under certain circumstances, men may actually benefit a bit more than women from the microbicides, which are compounds that can be applied inside the vagina.

Drug companies are running clinical trials on some second-generation microbicides based on antiretroviral, or ARV, medicines.

The study by the UCLA AIDS Institute also questions the designs of these trials. The researchers made the conclusions by using mathematical models that simulate clinical trials and population-level transmission of HIV.

Under the scenarios the researchers developed, men were slightly more protected than woman in certain situations. This occurred when the in-trial microbicide, an ARV drug called dapivirine, was only effective about half the time in women -- a situation that could occur if HIV-positive women on microbicides developed drug-resistant strains of HIV that were then less likely to be transmitted to men.

"The antiretroviral drugs within these microbicides are the same as those used to treat people who are infected with HIV, so there is great expectation that these microbicides will be very effective," said first author Dr. David Wilson, of the National Centre in HIV Epidemiology and Clinical Research at Australia's University of New South Wales, in a prepared statement.

"But the concern is that these microbicides are going to lead to drug resistance," he said.

Concerns about drug resistance come from the fact that the current clinical trial drops women from the study if they turn up HIV-positive during monthly screening, the researchers said.

"Since monthly testing will take place in the dapivirine trial, we predict that few, if any, cases of acquired resistance will arise during the trial, even if the drug is readily absorbed (i.e., the microbicide is high risk)," the researchers wrote. "Therefore, our analyses have shown that high-risk microbicides could pass Phase III trials, as their potential to cause resistance will be masked by frequent testing."

More information

The U.S. Department of Health & Human Services has more about HIV prevention drugs.