Age, race, socioeconomic factors increase risk of T. vaginalis

OB/GYN News,  July 15, 2006  by Damian McNamara

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JACKSONVILLE, FLA. -- First sex between ages 9 years and 15 years, lower socioeconomic status, and lower education levels are significantly associated with presence of Trichomonas vaginalis, according to the first report of T. vaginalis from a nationally representative sample of women in the United States.

A large racial disparity is another feature of T. vaginalis. Prevalence rates are 11 times greater among non-Hispanic blacks, compared with non-Hispanic white and Mexican American women.

"Routine screening in certain settings may be appropriate to decrease rates of disease and adverse reproductive health outcomes," Dr. Emilia Koumans said at a conference on STD prevention sponsored by the Centers for Disease Control and Prevention.

Using 2001-2002 data from the National Health and Nutrition Examination Survey (NHANES), Dr. Koumans, lead author Dr. Madeline Y. Sutton, and their associates assessed 1,999 self-collected vaginal swabs for presence of T. vaginalis. Study participants were 14-49 years old. Mexican Americans and adolescents were oversampled in the NHANES data to better represent the general population, said Dr. Koumans, a medical officer in the division of STD prevention at the CDC.

An estimated 3.1% overall prevalence of T. vaginalis was determined using polymerase chain reaction testing. Non-Hispanic black participants had a prevalence of 13.5%, compared with 1.5% for Mexican Americans and 1.2% for non-Hispanic whites.

T. vaginalis is a very common sexually transmitted disease, Dr. Koumans said, with an estimated 170 million new cases per year worldwide. "From my understanding of the literature, the predominant mode of T. vaginalis [transmission] is through sex," she said in response to a meeting attendee question. "There have been a few documented cases where it was through wet washcloths. The non-sexually transmitted cases are extremely rare."

Women can have trichomoniasis without any symptoms, or infection can manifest as abnormal vaginal discharge and/or bleeding from cervicitis.

Severe adverse outcomes include increased risk of other STDs, preterm labor, preterm birth, and increased risk of HIV acquisition and transmission--the latter probably from local tissue inflammation, Dr. Koumans said.

Another meeting attendee asked how many women in the study were asymptomatic. "We have not looked at that yet, my guess is a lot would be asymptomatic," Dr. Koumans replied. Data evaluation is ongoing, she added.

Women over age 30 years had the highest prevalence of T. vaginalis in the study. "Other studies have shown this trend toward greater prevalence in older age groups," Dr. Koumans said.

Total number of sex partners in the previous year was not associated with presence of T. vaginalis. A multivariate analysis of the data now underway will assess age independent of lifetime sex partners, Dr. Koumans said.

"Are these new infections in these older women?" an attendee asked. "We are not clear about that yet. Dr. Sutton proposes there may be a change in the vaginal epithelium with age," Dr. Koumans said.

Because T. vaginalis is associated with the presence of other sexually transmitted diseases, the next step for the researchers will be to look at concomitant STDs, Dr. Koumans said. "We want to see if they are in the same people or not, and how risk factors affect multiple STDs."

BY DAMIAN MCNAMARA

Miami Bureau

COPYRIGHT 2006 International Medical News Group
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