Chlamydial infection in women along the US-Mexico border.

Few studies have reported on sexually transmitted infections at the US-Mexico border, so the prevalence of Chlamydia trachomatis in this population remains uncertain. This binational project investigated the prevalence of, and risk factors for, C. trachomatis among women along the Arizona, US-Sonora, Mexico border. Women who self-referred for routine gynaecological care were invited to complete an interviewer-administered questionnaire and to undergo a Pap smear, C. trachomatis test, and HPV test. In 2270 women, C. trachomatis prevalence overall was 8.2% as measured by hybrid capture and 2.6% by enzyme immunoassay. Infection was associated with young age, a history of new sexual partner(s) in the previous three months, HPV infection, and proximity of clinic to the international border. Antibiotic use in the previous 30 days was associated with decreased odds of infection. Women in Arizona-Sonora border communities are at increased risk for C. trachomatis infection compared to women attending clinics in non-border locations.

Design and results of the USA-Mexico border human papillomavirus (HPV), cervical dysplasia, and Chlamydia trachomatis study.

OBJECTIVE: Mexico has one of the highest mortality rates of invasive cervical cancer in the world. This is particularly true for the states in northern Mexico that border on the United States of America. In addition, Hispanics in the United States have higher rates than do non-Hispanics in the country. Therefore, a binational team was formed to focus on this problem and to determine the risk factors and prevalence of cervical dysplasia and human papillomavirus (HPV) infection, the sexually transmitted disease (STD) known to cause cervical cancer. Chlamydia trachomatis infection, a common STD and potential HPV cofactor, was also assessed. METHODS: Research was conducted in 1997 and 1998 in the border region of two states, Arizona in the United States and Sonora in Mexico, applying a cross-sectional study of women attending clinics for routine gynecologic care. Clinical measurements included Pap smears, HPV infection by both polymerase chain reaction (PCR) and Hybrid Capture (HC), and C. trachomatis status by HC and enzyme-linked immunoassay (EIA). A total of 2,436 women were enrolled (mean age 33.3 years +/- 10.3 years). RESULTS: The overall prevalence of abnormal cytology was 9.3%, with a significant difference in the prevalence in Mexico (11.4%) vs. the United States (6.6%). Of the participants, 14.5% of them tested positive for HPV by PCR, with no significant difference between the two countries, in spite of a lower behavioral risk profile for the Mexican women. Overall prevalence of C. trachomatis was found to be greater by HC than by EIA (8.2% vs. 3.0%), and in Mexico higher by both methods. CONCLUSIONS: An important accomplishment of the project was the implementation of a quality control program for Pap smear collection, which resulted in a significant reduction in inadequate smears in Mexico. Despite numerous potential logistical barriers, the binational team successfully conducted a large-scale study in the border area and developed an infrastructure for future research.