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Chlamydia Prevalence Among College Students: Reproductive and Public Health Implications

James, Adelbert B. PhD, MPH*; Simpson, Tina Y. MD, MPH; Chamberlain, William A. MPA*

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Sexually Transmitted Diseases: June 2008 - Volume 35 - Issue 6 - p 529-532
doi: 10.1097/OLQ.0b013e3181676697
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CHLAMYDIA TRACHOMATIS IS THE MOST commonly reported sexually transmitted infection (STI) in the United States.1 An estimated 2.8 million chlamydial infections occur annually and approximately 48% of reported cases occur among sexually active young adults between the ages of 15 and 24 years.2 Chlamydial infections are asymptomatic in most sexually active women who have the highest risk for this infection.3 Risk factors for chlamydial infections include young age and age at coital debut of less than 15 years.4–7

Sexual Risk Behaviors Among College Students

To date, studies on sexual practices and STIs among college students have been limited. The 1995 National College Health Risk Behavior Survey8 monitored a broad range of priority health risk behaviors among college students, including sexual behaviors that lead to unintended pregnancy and STIs. The results of the survey revealed that 86.1% of college students have had at least 1 sexual encounter. At least two-thirds were currently sexually active or had sex within the last 3 months. Approximately 30% of the respondents reported condom use at their last sexual encounter and 28% reported using condoms consistently. These findings suggest the need to develop strategies to increase awareness in reducing the transmission of STIs.

College-Based STI Services

Despite the high-risk behaviors exhibited among students, routine chlamydia screening is not available at most student health centers. Koumans et al.9 conducted a randomized stratified survey of 736 colleges and universities to estimate the proportion of schools offering STI services and the proportion of students with access to such services. The study revealed that STI services were available at 66% of colleges/universities that had a student health center and 52% of students attended a school where chlamydia and gonorrhea testing were available. Although most schools with STI services test symptomatic women and men for chlamydia and gonorrhea, only 67% of schools screen sexually active women and 48% of schools screen sexually active men.9

The availability of the highly sensitive nucleic acid amplification test (NAAT) has increased the capacity to screen for chlamydia infections among asymptomatic persons and estimate the prevalence of chlamydia which varies by gender, race, ethnicity, and geographical locations.10 The ability for NAATs to detect organism using urine specimens has also facilitated mass screening in nonclinical settings.11–13 The use of NAATs provides opportunities for routine chlamydia screening among students at student health centers.

The purpose of this study was to assess the prevalence of chlamydial infections among college students who volunteered for screening and to compare chlamydia positivity by selected demographic variables.

Materials and Methods

Background to the Study

The Region IV Infertility Prevention Project Advisory Committee identified student health centers at 12 colleges/universities in 3 states to provide free chlamydia and gonorrhea screening to students during a chlamydia awareness campaign in April 2004. All the colleges/universities were considered major schools in their respective cities. The student health centers were selected based upon accessibility and school officials' willingness to participate in the campaign. A total of 10 schools in Alabama (2), Georgia (5), and Mississippi (3) agreed to participate in the screening.

Of the 10 schools that participated, 6 were of historically black colleges and universities and 7 were state-owned institutions. All institutions offered undergraduate and graduate programs and were located in urban areas. Each school provided housing for students and the schools' enrollment ranged from 2000 to over 31,000 students.

We initiated several meetings with student health coordinators to discuss logistics and screening schedules during the campaign. Other discussions focused on student confidentiality, screening protocols and procedures, reporting, treatment, and follow-up with sexual partners of students who tested positive. Some schools promoted the campaign via e-mails, flyers and student radio stations with the assistance of student organizations.

Screening was voluntary to all students at each campus. After receiving general information on chlamydia, students agreed to be screened by signing an informed consent form to provide urine specimens. In Alabama and Mississippi, urine specimens were tested using APTIMA COMBO 2 Assay, (Gen-Probe, San Diego, CA). In Georgia, urine specimens were tested using BD PROBETEC Strand Displacement Assay, (Becton Dickinson, Franklin Lakes, NJ). All specimens were shipped to the respective state public health laboratories. Demographic data were collected on each student, but not behavioral risk factors and clinical information. In Georgia, student classification was obtained from each student.

The state public health laboratories submitted test results to each student health center and students were notified of their results. Students who tested positive for either chlamydia or gonorrhea were treated according to the Center for Disease Control and Prevention treatment guidelines at their student health center. The staff at each student health center encouraged infected students to notify their sexual partners about the availability of testing and treatment at the local health department.

Data Analysis

The data were obtained from the Region IV Chlamydia Prevalence Monitoring Project. An Institutional Review Board from Emory University School of Medicine was approved to analyze the data using the Statistical Package for Social Science (SPSS) version 13 (SPSS, Chicago, IL). Students were categorized into 3 age groups: <20 years, between 20 and 24 years, and >24 years. Schools were classified into 3 enrollment categories: <5000, between 5000 and 10,000, and >10,000 students.

We also used selected demographic variables to estimate the prevalence of chlamydia by age group, gender, race, college classification, state, and school enrollment. The test statistics (χ2) was used to obtain odds ratios (ORs) and 95% confidence intervals (CI) to assess the strength of associations and determine statistical significance.


Characteristics of Participating Students

A total of 789 students were screened for chlamydia and gonorrhea. The median age was 20 years. Table 1 represents the frequency distribution of students screened by age group, gender, race, state, and student enrollment. Subjects consisted of 263 students under the age of 20 years and 526 older students. More than half of the students (57%) were females and 80% of students were blacks. Approximately 60% of students resided in Georgia, which had the lowest chlamydia prevalence among all 3 states. Most of the subjects (42%) attended schools with a student enrollment >10,000, followed by 34% attended schools with <5000 students and 24% attended schools with an enrollment between 5000 and 10,000 students.

Demographic Characteristics of Participating Students

Prevalence of Infections

The chlamydia prevalence among all students was 9.7%. In Alabama and Mississippi, students under the age of 20 years had a chlamydia prevalence of 17.1% and 16.9%, respectively. In all 3 states, younger students had the highest chlamydia prevalence. Students under the age of 20 years were more likely to have chlamydial infections than older students (OR 1.66; 95% CI 1.01–2.73) (Table 2). Female students under the age of 20 years were more likely to be infected than were older female students (OR 1.92; 95% CI 1.03–3.59). In Georgia, freshmen were more likely to be infected than were seniors (OR 5.1; 95% CI 1.09–24.12). Overall, younger students had a chlamydia prevalence of 13% compared with 8.4% among older students. Schools with a total student enrollment of between 5000 and 10,000 had the highest chlamydia prevalence of 15.5%. Schools with a student enrollment of between 5000 and 10,000 were more likely to report chlamydia than schools with an enrollment of less than 5000 students (OR 1.98; 95% CI 1.11–3.53); and more likely to report chlamydia than schools with an enrollment of >10,000 students (OR 2.5; 95% CI 1.40–4.49). The chlamydia positivity among students under the age of 20 years who attended schools with a total enrollment of between 5000 and 10,000 was 21.2% (Table 3).

Odds Ratio of the Association between Chlamydial Infection and Selected Students' Characteristics
Chlamydia Positivity by Student Enrollment

The prevalence of gonorrhea among all students was 1.5%. A total of 11 cases were reported and 72% of all cases were reported among schools with an enrollment of between 5000 and 10,000 students. There was no significant difference in gonococcal infections by either age group or gender.

A total of 456 women and 333 men were screened. In Alabama and Mississippi, females had higher chlamydia prevalence when compared with males. However, there was no significant difference in chlamydial infections between males and females. In all 3 states, younger females had higher chlamydia prevalence than older students.

Although the screening was opened to both blacks and white students, blacks were more willing to be screened than whites. The results revealed a major disparity between both races. The chlamydia prevalence among blacks was 11.0% compared with 1.0% among white students.


Organized efforts to screen college students for chlamydial infections have been sparse. In 2 previous screenings among college students, the overall chlamydia prevalence was relatively low. In a California collegiate population in which 4086 students were screened, the overall chlamydia prevalence was 3.4% between 2000 and 2002.14 At a university in West Virginia, the chlamydia prevalence declined from 8.8% to 3.5% between 1989 and 1994.15 The higher prevalence of 9.7% in this study reflects the chlamydia prevalence (10.9%) in the southeast which has considerable higher rates of STIs.16

The results of this study reveal that the chlamydia prevalence was high among college students compared with 2.2% in a nationally representative study of chlamydia prevalence in the general population. The findings which were obtained from the National Health and Nutrition Examination Survey (NHANES) indicated that the highest prevalence of 4.6% was among women between the ages of 14 to 19 years. In blacks, the prevalence was 6.4% compared with 1.5% among whites.17 The current awareness campaign highlights the efforts of IPP to extend chlamydia screening to nontraditional screening sites such as college and universities.

Overall, our findings reveal that younger students are more likely to be infected with chlamydia than older students and younger females are more likely to be infected than older female students. These results are consistent with national data reports that younger age is a risk factor for chlamydia.18 There are at least 2 explanations for these results. Possibly, younger students who are away from parental control seek to explore and engage in high-risk sexual behaviors. They are more likely to have unprotected sexual intercourse and have multiple sexual partners; they are more likely to have partners who are at higher risk for STIs.19 During the first year at college, both male and female students tend not to be monogamous and 38% of young women experiencing their first sexual encounter use condoms.20

Second, younger women are more susceptible to chlamydial infections compared with older women due to cervical ectopy which causes the cervix to be more sensitive to microorganisms.19 During adolescence, columnar epithelial cells from the endocervix extend to the vaginal surface and increase the surface area for C. trachomatis infections. If infections remain undetected or untreated, these women may develop reproductive health complications.

Screening was voluntary and offered to all students. We did not identify or target any particular school or racial group; however, blacks were more willing to be screened than any other racial groups. One possible explanation why more blacks were screened may be because of the increased awareness of high rates of STIs in their communities. Students who volunteered for the test may have consented due to past risky sexual behaviors, curiosity, or increased chlamydia awareness. We are unable to explain the students' reasons for health-seeking behaviors. However, the overall chlamydia prevalence of nearly 10%, demonstrates the need for more studies on health-seeking behaviors among students.

The disproportionate large numbers of cases among black students is a public health concern. These findings are consistent with other reports that blacks are 8 times more likely to have chlamydia and 18 times more likely to have gonococcal infections than whites.18 More studies are needed to examine the role of sociodemographics and sexual networks and their influence on transmitting STIs among blacks.

The expansion of chlamydia screening at colleges and universities was not without obstacles. Initial barriers included the reluctance of school administrators to accept that STIs may be present among students, and the fear that the school's reputation may be diminished if STIs were prevalent. As a result of educating school officials regarding the consequence and risks of STIs and assurance of student confidentiality, we were able to gain the acceptance of some colleges and universities. Other barriers include the timing of the campaign, conflicts with exam schedules and the designation of sufficient space for private specimen collection and coordination with local health departments for treatment. These issues warrant careful consideration in planning of future campus-wide screening campaigns.

This study has several limitations which may impact the outcome of our results. Because the participants were self-selected, the results may not be representative of all college students and should not be generalized to all students. Furthermore, we did not collect behavioral risk information, which may help to explain the high prevalence of the infection.

The results of this study underscore the importance of promoting routine screening at student health centers to students who are at risk for complications to untreated chlamydial infections. As the screening was conducted at the end of the school year, it was difficult to determine whether young freshmen were in infected during high school or their first year at college. It would be advantageous to begin screening during the fall semester to determine the time of infection. The results of screening during the fall semester may indicate an increased need to offer routine screening in high schools. Approximately 25% of adolescents acquire at least 1 STI before graduating from high school.21

This study suggests the need for strengthened STI risk reduction/prevention campaigns at colleges and universities. Through collaborative efforts between college students, health officials and researchers, the evaluation of existing STI education and prevention messages is warranted. Deficiencies in such preventive messages need to be addressed to improve the reproductive health of young adults.


1. Center for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2004 Supplement, Chlamydia Prevalence Monitoring Project. Atlanta: U.S. Department of Health and Human Services, 2005.
2. Weinstock H, Berman S, Cates W Jr. Sexually transmitted diseases among American youth: Incidence and prevalence estimates, 2000. Perspect Sex Reprod Health 2004; 36:6–10.
3. Shrier LA, Dean D, Klein E, et al. Limitations of screening tests for the detection of Chlamydia trachomatis in asymptomatic adolescent and young adult women. Am J Obstet Gynecol 2004; 190:654–662.
4. Bontis J, Vavilis D, Panidis D, et al. Detection of Chlamydia trachomatis in asymptomatic women: Relationship to history, contraception, and cervicitis. Adv Contracept 1994; 10:309–315.
5. Miller HG, Cain VS, Rogers SM, et al. Correlates of sexually transmitted bacterial infections among U.S. women in 1995. Fam Plann Perspect 1999; 31:4–9, 23.
6. Radcliffe KW, Ahmad S, Gilleran G, et al. Demographic and behavioural profile of adults infected with chlamydia: A case-control study. Sex Transm Infect 2001; 77:265–270.
7. Paukku M, Kilpikari R, Puolakkainen M, et al. Criteria for selective screening for Chlamydia trachomatis. Sex Transm Dis 2003; 30:120–123.
8. Douglas KA, Collins JL, Warren C, et al. Results from the 1995 National College Health Risk Behavior Survey. J Am Coll Health 1997; 46:55–66.
9. Koumans EH, Sternberg MR, Motamed C, et al. Sexually transmitted disease services at US colleges and universities. J Am Coll Health 2005; 53:211–217.
10. Schachter J, McCormack WM, Chernesky MA, et al. Vaginal swabs are appropriate specimens for diagnosis of genital tract infection with Chlamydia trachomatis. J Clin Microbiol 2003; 41:3784–3789.
11. Quinn TC. DNA amplification assays: A new standard for diagnosis of Chlamydia trachomatis infections. Ann Acad Med Singapore 1995; 24:627–633.
12. Lee HH, Chernesky MA, Schachter J, et al. Diagnosis of Chlamydia trachomatis genitourinary infection in women by ligase chain reaction assay of urine. Lancet 1995; 345:213–216.
13. Bloomfield PJ, Kent C, Campbell D, et al. Community-based chlamydia and gonorrhea screening through the United States mail, San Francisco. Sex Transm Dis 2002; 29:294–297.
14. Sipkin DL, Gillam A, Grady LB. Risk factors for Chlamydia trachomatis infection in a California collegiate population. J Am Coll Health 2003; 52:65–71.
15. Cleavenger RL, Juckett RG, Hobbs GR. Trends in chlamydia and other sexually transmitted diseases in a university health service. J Am Coll Health 1996; 44:263–265.
16. Crosby RA, DiClemente RJ, Wingood GM, et al. Correlates of continued risky sex among pregnant African American teens: Implications for STD prevention. Sex Transm Dis 2003; 30:57–63.
17. Datta SD, Sternberg M, Johnson RE, et al. Gonorrhea and chlamydia in the United States among persons 14 to 39 years of age, 1999 to 2002. Ann Intern Med 2007; 147:89–96.
18. Steele C, Melendez-Morales L, Campoluci R, et al. Health Disparities in HIV/AIDS, Viral Hepatitis, Sexually Transmitted Diseases, and Tuberculosis: Issues, Burden, and Response, A Retrospective Review, 2000–2004. Atlanta: Department of Health and Human Services, Center for Disease Control and Prevention, 2007.
19. Institute of Medicine (U.S.). Committee on Prevention and Control of Sexually Transmitted Diseases. In: Eng TR, Butler WT, eds. The Hidden Epidemic: Confronting Sexually Transmitted Diseases. Washington, DC: National Academy Press, 1997.
20. Roberts ST, Kennedy BL. Why are young college women not using condoms? Their perceived risk, drug use, and developmental vulnerability may provide important clues to sexual risk. Arch Psychiatr Nurs 2006; 20:32–40.
21. Holland-Hall CM, Wiesenfeld HC, Murray PJ. Self-collected vaginal swabs for the detection of multiple sexually transmitted infections in adolescent girls. J Pediatr Adolesc Gynecol 2002; 15:307–313.
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