Chlamydial Infection among Young Adults: Selective Screening and Partner Age Difference an Investigation of the National Longitudinal Study of Adolescent Health

Among young adults, chlamydial infection is the most common bacterial sexually transmitted infection. Women and minorities are most affected. Screening rates are low despite recommendations for yearly testing. Programs to expand testing to community settings may increase screening rates. To examine this and other questions, we conducted a cross-sectional analysis of Wave III of the National Longitudinal Study of Adolescent Health (April 2, 2001 – May 9, 2002). Chlamydia trachomatis test results were available for 10,928 (88.6%) of the sexually experienced participants. First, we developed selective screening guidelines for community settings. Separately for women and men, we developed three predictive models using unconditional multiple logistic regression. The initial models included predictor characteristics plus information on 1) respondent’s race/ethnicity; or 2) respondent’s most recent partner’s race/ethnicity; or 3) no information on race/ethnicity. A combination of characteristics provides potentially useful screening tools. Applying these models to select ≤ 50 percent of the population for diagnostic testing identifies approximately 80 percent of infections in women and men. Using race/ethnicity in any screening algorithm is controversial and may have significant consequences. The model without race information, however, resulted in many missed diagnoses in the minority group. Universal screening for chlamydial infection may be the only approach that reaches high prevalence populations while avoiding the stigma of screening guidelines incorporating race/ethnicity. Second, we evaluated the association between partner age difference and chlamydial infection among young women. Adolescent girls with older male partners are at higher risk of STI compared to girls with partners their own age, but whether this association continues beyond adolescence is unclear. After multiple logistic regression, the odds of prevalent chlamydial infection among women with partners two to eight years younger were nearly two times greater (odds ratio (OR) 1.8, 95% confidence interval (CI) 0.9 – 3.5) than partners within one year’s age. Among women with older partners, the adjusted odds of infection were similar for partners two to five years older (OR 1.4, 95% CI 0.9 – 2.3) and partners six to 36 years older (OR 1.6, 95% CI 0.9 – 2.8). Among young adult women, older partners are moderately associated with prevalent chlamydial infection