Evaluations of STD/HIV interventions incorporating behavioral and biologic outcomes have not reported strong correspondence.
The goal of the study was to demonstrate that behaviors, measured comprehensively, are associated with infection and to delineate the behaviors responsible for reduced infection rates in Project SAFE (Sexual Awareness For Everyone).
Follow-up data from an intervention trial were analyzed to determine: (1) study versus control differences in complex risk behaviors and (2) the overall relationship between these behaviors and infection status (chlamydia and/or gonorrhea), with use of multiple logistic regression.
Lower infection rates among 249 women who received intervention (compared with 228 controls) were explained by reduced-risk status in 5 modifiable behaviors. The 0 to 12–month logistic regression model (including sex with untreated partner [OR = 5.6], lack of mutual monogamy [OR = 2.4], unsafe sex [OR = 1.9], rapid partner turnover [OR = 2.7], and douching after sex [OR = 1.9]) correctly predicted infection status for 75.3% of participants (71.8% of infected, 76.2% of uninfected). Women in nonmutually monogamous unions who had sex with partners who were untreated or incompletely treated were 13 times more likely to be infected than those who were monogamous and avoided sex with an untreated/incompletely treated partner.
This intervention reduced infection rates by maintaining low-risk behaviors and changing high-risk behaviors. We elucidated the complex relationship between behavior and infection by incorporating context into variable conceptualization and considering several behaviors simultaneously.
Reduced risk status in five modifiable behaviors, measured comprehensively with attention to context, explained reduced infection rates among women who received intervention, compared with those who did not.
From the *Department of Obstetrics and Gynecology, †Department of Microbiology, and ‡School of Nursing, The University of Texas Health Science Center at San Antonio, Texas; and the §Department of Obstetrics and Gynecology, East Carolina University, Greenville, North Carolina
The authors thank Willard Cates, Jr., MD, MPH, for his thorough review and helpful suggestions.
Supported by a grant (UO1 AI31498) from the National Institute of Allergy and Infectious Disease.
Reprint requests: Rochelle N. Shain, PhD, Department of Ob/Gyn, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900.
Received for publication August 13, 2001,
revised November 7, 2001, and accepted December 12, 2001.