from www.usnews.com — The use of lubricants during unprotected anal intercourse may indirectly raise the risk of HIV transmission in the receptive partner, among both men and women, new research warns.

Concern about the possibility is being raised in the form of two new studies, and revolves around the fact that HIV infection risk rises if other infections are already present in the rectal lining of the receptive partner, the study authors noted.

In that light, indications that some lubricants may contribute to a generally increased risk for sexually transmitted infections, and therefore in turn for HIV, are scheduled for presentation this week in Pittsburgh at the International Microbicides Conference.

Conducted between 2006 and 2008, one study — which focused on approximately 900 residents in the Baltimore and Los Angeles region — observed that men and women who use lubricants in general are three times more likely to have some form of a rectal sexually transmitted infection. The finding held regardless of gender, HIV status, condom use, and the number of sex partners the study participants had had in the prior month.

Although no specific lubricants were identified as particularly problematic, most study participants said they used a water-based lubricant (76 percent), while 28 percent used silicon-based products, 17 percent oil-based lubricants, and 6 percent said used a numbing lubricant.

The second study — led by Charlene Dezzutti of the University of Pittsburgh and the Microbicide Trials Network — looked at five of the most popular over-the-counter and/or mail-order lubricants, identified as such through a survey of 9,000 men and women living in 100 different countries.

All the lubricants were water-based, except for one silicon-based product.

The research team — including collaborators from International Rectal Microbicide Advocates (IRMA) — did not examine the effect of lubricant use during actual sex. However, in laboratory testing, some of the lubricants were found to have a toxic effect on cells and rectal tissue, perhaps as the result of the dissolved salts and sugars the products contained.

PRE and Wet Platinum were found to be the safest lubricants in terms of toxicity, whereas Astroglide and KY Jelly appeared to be the most problematic.

“We know we can’t make any conclusions based on this one small study,” cautioned IRMA lubricant safety advocate Marc-Andre LeBlanc, in a news release. “Further research is absolutely necessary to understand the potential role of sexual lubricants in HIV transmission. We should be able to provide consumer guidance regarding lubes that are found to be safer than others.”

“Some lubes are probably better than others, but we don’t know where any of the currently available products fall along the spectrum from good to bad,” added IRMA chair Jim Pickett.

“We must ensure that existing lubes don’t facilitate HIV transmission,” he added. “People have a right to this kind of information, and it’s very past due.”

Conference organizers pointed out that in the United States, 90 percent of men who have sex with men — whether self-identified as gay or not — engage in receptive anal intercourse. Between 10 percent and 35 percent of heterosexual women have done so at least once. And in either instance, condoms are often not used, while lubricants are.