Prevalence of Undetected Gonorrhea and Chlamydia Infection May Be As High As Number of Recorded Cases, JAMA Study Says

According to a study conducted in Baltimore and appearing in today's Journal of the American Medical Association, the number of untreated gonorrhea and chlamydia infections may equal or exceed the total number of cases that are diagnosed and treated, Reuters Health reports (Reuters Health, 2/12). Charles Turner of the Research Triangle Institute and colleagues conducted a cross-sectional behavioral survey of 728 Baltimore adults between the ages of 18 and 35 -- who were chosen using a stratified sampling of residences from the Baltimore Real Estate Property Registry from January 1997 to September 1998 -- and found that the number of undiagnosed and untreated infections of gonorrhea and chlamydia exceeded the number of infections that were diagnosed and treated during the same time period. The researchers interviewed participants about their sexual health histories and obtained urine specimens from 579 of the respondents to test for gonococcal and chlamydial bacteria. Participants received $10 to $20 for answering the questionnaire and an additional $10 to $20 if they supplied a urine specimen.

Results
After determining the number of infections and extrapolating the results to the general public, researchers found that the prevalence of untreated gonorrhea was 5.3%, while the prevalence of untreated chlamydia was 3%. Altogether almost 8% of adults -- close to one in 12 -- between the ages of 18 and 35 in Baltimore had one or both types of infection. By comparison, in 1998, 4,566 cases of gonorrhea in people between the ages of 18 and 35 were officially recorded in Baltimore, making the maximum reported population prevalence 2.6%, about half of the study's assessment of actual prevalance at 5.3%. Similarly, 3,664 chlamydial infections were recorded for a reported prevalence of 2.1% compared with the study's findings of actual prevalence of 3%. The prevalence of the two bacteria "varie[d] substantially across subpopulations," the researchers state, noting that 15% of black women were estimated to have one or both infections, compared to only 1.3% of non-black women. Gonorrhea was more prevalent than chlamydia among blacks and women. Prevalence of the two diseases was also higher among black men compared to non-black men, but the difference was not statistically significant. Chlamydia prevalence declined significantly with increasing age, although gonorrhea prevalence was highest among people between the ages of 31 and 35. Symptoms were rarely reported; only 2% of infected individuals reported burning upon urination and only 4.7% reported discharge within the six months prior to the survey. Researchers suggested that the lack of physical symptoms might help explain why treatment had not been sought and obtained in more of the cases.

Recommendations
"[P]rompt consideration should be given to strategies for improving the diagnosis and treatment of asymptomatic infections" in Baltimore adults between the ages of 18 and 35, the researchers state, adding that it is "prudent to plan appropriate public health actions in response to the high prevalence" detected by the study. They suggest implementing routine screenings in health care settings for all young adults. The researchers also recommend that further epidemiological STD surveys be undertaken using the same combination of population survey techniques and analysis, noting that the study's success "provides an example of the feasibility and benefits" of the approach. They add that because teenagers "contract infections from and transmit infections to the adult population, any replication" of the study should include teens in its survey population (Turner et al., Journal of the American Medical Association, 2/13).

STD Surveillance 'Far From Complete'
The study by Turner and colleagues demonstrates that STD control and prevention efforts are "far from complete," J. Dennis Fortenberry of the Indiana University School of Medicine writes in an accompanying JAMA editorial. "It is clear that clinicians can do a better job with sexual health risk assessments, STD screening and treatment and partner notification and treatment," he states, adding, "Embarrassment on the part of the patient or clinician or poor assessment of sexual health risk are common but not satisfactory reasons for avoiding this task." STD surveillance systems should be updated to include population-based surveys, such as Turner's, which would "provide a more accurate picture of the burden of STD and more appropriate benchmarks for assessment of STD control efforts." However, "[t]he veils surrounding STDs are not simply those of inadequate documentation of disease prevalence. Societal willingness to stigmatize sexuality and STDs continues to hide issues that are central aspects of our lives." He concludes, "Given the morbidity and costs of STDs, including those due to HIV infection, these are veils that no longer seem affordable" (Fortenberry, JAMA, 2/13). Bacterial STDs such as gonorrhea and chlamydia "serve as biological cofactors that facilitate" HIV transmission. People infected with chlamydia are between 1.4 and 3.3 times more likely to acquire HIV (Turner et al., JAMA, 2/13). A report on the study from NPR's "Morning Edition" will be available in RealAudio online after noon ET (Jones, "Morning Edition," NPR, 2/13).