May 9, 2006 -- Chlamydia is one of the most common sexually transmitted diseases in the United States, and its impact is huge -- not only can it cause infertility in women, it also increases the risk of catching HIV from an infected partner.
A slew of new research studies on the infection being presented this week at a national STD conference shows that chlamydia can be surprisingly common among younger women -- especially college freshmen, one of the studies shows. In another study, "repeat" infections were common, too.
Even more important, experts note, is the fact that health practitioners still don't have solid national numbers on just how many women and men have the infection. This is because, in part, not enough doctors are screening for the infection and reporting infections when they uncover them, experts said at a news briefing today at the 2006 National STD Prevention Conference, sponsored by various state and national health agencies.
It is estimated that 2.8 million cases occur each year, with the majority of those being undiagnosed and untreated, health officials say.
"The [Centers for Disease Control and Prevention] recommends that all sexually active women under the age of 26 be screened annually, but studies have shown that many of these women are not being tested," said Dr. Ronald Valdiserri, deputy director of the CDC's National Center for HIV, STD and TB Prevention.
As a result, just how many people are actually infected is hard to know, with scientists only able to estimate. However, some new research is shedding some light.
In one evaluation, 780 college students were screened voluntarily for chlamydia at 10 colleges in the Southeast. Close to 10 percent of them tested positive for chlamydia, and when the numbers were broken down just to look at rates among freshman students, the percent infected rose to 13.
"It underscores the importance of screening among all students, primarily female freshmen," said Dr. Adelbert James of the Emory University School of Medicine.
Men probably have similar rates of infection, but the consequences are not as dire. If left untreated in women, chlamydia can scar the fallopian tubes, which can cause infertility. In men, complications are rare but, like women, include infertility and scarring of the urethra.
In another study, one in every eight females ages 10 to 29 who tested positive for chlamydia had a repeat infection within one year. The study also found that the repeat infection rate for adolescent females -- ages 10 to 19 -- was more than double the rate seen in women ages 25 to 29.
Why are younger women disproportionately affected? It's probably for a number of reasons, health experts say.
First, the cellular structure of the genital tissue of younger women allows more infections to invade. Also, older women are more monogamous, see doctors more often, and may have stronger immune systems.
"How much access does a woman have to health care? Many [young] women just don't go to health services. They are at college. They are independent," said Dr. Marc Laufer, chief of gynecology at Children's Hospital Boston. "You cannot guarantee that women even go in to see a doctor."
Regardless, screening young women is important, because it's now easy to do through a urine test, he said.
"This is a good recommendation," he said.