Racial Differences in Chlamydia Reported

Researchers Say Socioeconomic Differences Are the Most Likely Cause

From the WebMD Archives

May 11, 2004 -- Young blacks are six times as likely as young whites to be infected with chlamydia, and infection rates are nearly twice as high in the South as in the Northeast, according to a study of how common these sexual transmitted diseases are in young adults in the U.S.

Overall, the study shows that approximately 4% of young adults in the U.S. are infected with Chlamydia, a common sexually transmitted disease (STD). Women were only slightly more likely to be infected than men, but the difference was not highly significant, researcher William C. Miller, MD, PhD, tells WebMD. For this reason, he says infection control efforts -- such as screening for infection -- should include both sexes instead of targeting females alone, as is now the case.

Untreated chlamydial infection in women can lead to pelvic inflammatory disease, infertility, ectopic pregnancy, and possibly cervical cancer. It can also increase the risk of infection with HIV.

"This is a sexually transmitted disease, so unless infection control efforts include both sexes they probably won't have a major impact on infection rates," he says.

STD expert David Eschenbach, MD, of the University of Washington, agrees.

"The only hope we have of reducing the overall rate of chlamydial infections is to screen both men and women," says Eschenbach, who chairs the university's obstetrics and gynecology department. "Screening men isn't even on most people's radar screen, but it should be."

Healthcare Access Is Key

The study by Miller and colleagues from the University of North Carolina at Chapel Hill involved a nationally representative sample of more than 14,000 young adults between the ages of 18 and 26. The young adults were tested for Chlamydia infection.

Infection rates varied little by age, but widely by ethnicity. Approximately 2% of young, white adults participating in the study were infected with chlamydia, compared with 12% of blacks and 6% of Latinos. Asian men had the lowest rate of infection -- roughly 1%.

The study also looked at rates of infection of another STD -- gonorrhea. Overall the rates of infection were low but again higher infection rates were seen among young blacks (2%) than young whites (0.10%).


The findings are reported in the May 12 issue of the Journal of the American Medical Association.

Miller says the most likely explanation for the racial disparity is economic. Blacks and Hispanics as a group have less access to health care than whites because they are more likely to be poor. As a result, they are less likely to be screened for the infection and to be treated with antibiotics for other reasons.

In an earlier study, Miller's research team found a low rate of chlamydial infections and a high rate of antibiotic use among middle- and upper-class teens being seen at a pediatric clinic.

"It takes a much higher level of (sickness) for people who have no health care to go see a doctor," Miller says. "A middle-class kid who takes doxycycline for his acne may be unknowingly treating a [chlamydial] infection. This is the kind of thing that over a long period of time can perpetuate this disparity."

Regional Differences

Miller says socioeconomic factors may also explain the regional differences in infection rates. Chlamydial infection was found in almost 5.5% of the young people living in the South, almost 4% among those living in the Midwest, 3% among those living in the West, and almost 2.5% among those living in the Northeast.

Eschenbach says a historical reluctance to call for the screening of all sexually active young people comes from the fact that older tests for chlamydia were more expensive and less accurate than the tests used today. He tells WebMD that it is time for the CDC and other health-care groups to revisit and broaden their screening guidelines.

"Clearly the data are there to suggest that you can save a lot of money and a lot of grief by screening people for this STD," he says.

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SOURCES: Miller, C. Journal of the American Medical Association, May 12, 2004; vol. 291: pp 2229-2236. William C. Miller, MD, PhD, assistant professor of medicine and epidemiology, University of North Carolina at Chapel Hill. David Eschenbach, MD, chairman, department of obstetrics and gynecology, University of Washington; STDs spokesman, American College of Obstetrics and Gynecology.
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