May 27, 2010 (Pittsburgh, Pennsylvania) — The findings from a pair of studies presented here on the closing day of the Microbicides 2010 conference, sponsored in part by the University of Pittsburgh in Pennsylvania, indicate that some sexual lubricants can damage rectal and vaginal tissue, thereby increasing vulnerability to a number of sexually transmitted infections (STIs), including chlamydia and gonorrhea.
Concern that the use of sexual lubricants might increase the risk of acquiring HIV has led to investigation of not only those containing nonoxynol-9, but to a broader spectrum of products.
Researchers at the University of Pittsburgh screened 6 over-the-counter lubricants with the same measures used in the examination of potential microbicides. An online survey conducted by the International Rectal Microbicides Advocates (IRMA) identified the most commonly used of the more than 150 variants of commercially available lubricants. The basic formulation of each was used.
"What we saw was the gels that were hyperosmolar [the aqueous-based Astroglide, Elbow Grease, ID Glide, and K-Y Jelly] were actually damaging the epithelium of the rectal and cervical tissue," said Charlene Duzzetti, PhD, senior author of the study. "The one that was not hyperosmolar [PRé], that didn't have any salts in it, and the silicon-based one [Wet Platinum] did not show any damage."
She told Medscape Infectious Diseases that her team saw "the traditional sloughing with the hyperosmolar lubricants that were similar to nonoxynol-9." They did not see damage to the lamina propria, which nonoxynol-9 typically reduces by 60% to 70%, or a reduction in tissue viability. "The lubricants looked good when we measured them that way."
Their lab system is not capable of measuring inflammation, which in the case of nonoxynol-9 attracts CD4+ cells, the principle target of HIV infection.
Dr. Duzzetti said: "We speculate that this [physical damage] leaves one more vulnerable to infection because you are breaking that epithelial barrier."
Epidemiologic support for that position came from work by University of California, Los Angeles investigator Pamina M. Gorbach, PhD, and colleagues. The study involved 879 men and women in Los Angeles and Baltimore, Maryland.
Of that group, 229 men reported participating in receptive anal intercourse (RAI) in the previous month, and 192 women reported participating in RAI in the previous year. Complete computer-assisted self-interviews of sexual behavior and rectal tests for chlamydia and gonorrhea were available for analysis from 302 study participants. This subset of patients shared similar characteristics with the entire study population.
Participants reported using a variety of brands of lubricants, sometimes in combination: 76% used water-based products, 28% used silicon-based products, and 17% used oil-based [Crisco] products. There were no significant differences in the demographics of those who used the products.
Anal STIs were present in 25 of the 302 (9%) subset participants. Men and women who used lubricants at the last recorded RAI were about twice as likely to have chlamydia or gonorrhea as those who did not use lubricants (68% vs 32%; odds ratio, 3.14; P = .02).
Those bacterial infections were chosen for analysis because they tend to be transient and are suggestive of infection within the previous 1 to 3 months. Their incidence is about 1.5% a year.
Dr. Gorbach said that "this suggests that the use of some rectal lubricant products may increase the risk of STIs." She noted that the sample was not large enough to detect whether there were any differences between the types of products used.
Jim Pickett, chair of the IRMA, urged caution when interpreting these results until there are more definitive research findings. Anal intercourse without a condom and lubricant often results in tears and physical damage to delicate mucosal tissue that might be greater than the insult caused by a lubricant. Although some lubricants are better than others, perhaps using any lubricant is better than "dry" sex using no lubricant at all.
Dr. Duzzetti suggested that consumers might want to check the label when purchasing lubricants to look for products that are isotonic or isosmolar, or silicon-based and condom-compatible.
One encouraging note from her research, she said, is that vaginal and rectal tissue samples, sometimes from the same participant, responded similarly across the panel of tests used in the lubricant challenges. It suggests that a product that is safe in the vaginal compartment will be safe in the rectal compartment as well.
Both studies were funded by grants from the National Institutes of Health. The researchers have disclosed no relevant financial relationships.
2010 International Microbicides Conference (M2010): Abstracts 347 and 348. Presented May 25, 2010.
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Cite this: Some Sexual Lubricants Linked to Increased Risk for Chlamydia, Gonorrhea - Medscape - May 27, 2010.