TUESDAY, Dec. 30 (HealthDayNews) -- When women get yeast infections, men often get the blame. Males aren't immune to pesky species of fungus, and some experts assume they unknowingly transmit the disease to their wives and girlfriends.
But a new study suggests the situation isn't so simple.
Researchers found no direct connection between male sex partners and yeast infections in women, even if the men themselves were infected, too.
"This is a pretty good study for men," says study co-author Dr. Barbara Reed, a professor of medicine at the University of Michigan. "They've been getting a bum rap suggesting they were responsible for these recurrences, and it doesn't look to be the case."
Men aren't entirely off the hook, however. Females who engaged in sex acts involving saliva -- their own or their partner's -- were more likely to get infected repeatedly.
Yeast, a kind of fungus also known as Candida, can set up shop throughout the body, from the throat to the intestines to the genitals.
"It lives in the moist orifices of a lot of people's bodies and is part of their normal makeup," says Dr. Vera Stucky, assistant chief of obstetrics-gynecology with the Kaiser Permanente Health Plan in San Diego. Anywhere from 25 percent to 75 percent of people will be "colonized" at any one time, she says.
In many cases, especially in men, the infections don't cause symptoms. In women, however, yeast infections can disrupt the bacterial balance of the vagina, causing burning, itching, discharge and odor.
An estimated 70 percent of all women develop yeast infections during their lives, and about four in 10 become infected more than once. The infections can be treated with antifungal creams and drugs.
It's not clear what exactly causes yeast infections, Reed says. "A number of risk factors have been discussed over the years, such as dietary risks, such as eating a lot of sugar and yeast, or oral contraceptives, pregnancy and AIDS. But most of the time, when we see a woman with a yeast infection, we don't find any good reason for her to have the infection."
Men, however, seem to be an obvious culprit. "People have speculated that we treat the woman and get rid of the yeast, then the partner carries the yeast and reinfects her. There have been some studies where they tried treating both the man and woman, but it really didn't seem to make a difference."
In the new study, Reed and colleagues studied 148 women with yeast infections and 78 of their male sex partners. (Only a small number of lesbians took part, and they were not included in the study statistics.) Researchers followed the subjects for one year, testing both the men and women to see if yeast had colonized their mouths, intestines or genitals.
The findings of the study appear in the December issue of the Journal of Women's Health.
Thirty-three of the women went on to develop new yeast infections. They were 2.6 to 2.9 times more likely to get infected again if they recently engaged in cunnilingus (oral sex upon a woman) or masturbated with saliva (either theirs or their partner's). It didn't seem to matter if their male partners were infected or how often they had genital intercourse, Reed says.
"We're speculating that there's some interaction between components in the saliva and her vaginal wall that makes her more likely to develop symptoms as she reacts to the [yeast] that might be present."
Stucky says it's not a surprise to find men aren't responsible for yeast infections. "It went along with our medical thinking that men really aren't the link."
The potential connection to saliva is mysterious, she says, and the researchers "really couldn't really explain that." They did, however, suggest that saliva may cause tears in tissue or disrupt the vagina's "delicate equilibrium," perhaps by changing how the immune system reacts to invaders.
What to do? Reed suggests that women who repeatedly get yeast infections take a break from the two possible risky sexual acts: cunnilingus and masturbation with saliva. "You may want to see if cutting back gives you a longer time without infection."
Happily, there is some good news. "This doesn't mean that oral sex is a risk for everybody," Reed says. "If you don't tend to have recurrent yeast infections, it's probably not a problem."
More information
To learn more about yeast infections, try the National Women's Health Information Center or the National Institutes of Health.
