Sexual Behavior Patterns and Condom Use in Newly Sexually Active Female University Students

Thesis (Master's)--University of Washington, 2016-06

Objectives: Describe sexual behavior patterns and condom use in newly sexually active female university students. Methods: We conducted a retrospective cohort study (years 2000 – 2007) of university women enrolled either before or within three months of sexual debut who completed Web-based sexual behavior diaries biweekly and attended clinic visits every four months for up to four years during the study period (N = 250). Participants reported daily information on acts of intercourse, condom use, and partner and partnership characteristics in the diaries. We calculated frequency of intercourse, proportion of events that were condom-protected, and the incidence rate of new partner acquisition. We used generalized estimating equations to describe changes in sexual frequency and condom use over time; multiple logistic regression to examine factors associated with condom use at sexual debut; Kaplan-Meier methods to describe the cumulative incidence of condom non-use after use at debut, and Cox proportional hazards ratios to examine factors associated with condom non-use. Results: One hundred eighty-eight women had at least one male sex partner prior to enrollment or during follow-up, and 117 had first intercourse with a male partner while on study. Women had sex on average 1.7 times per week, though frequency declined as partnership length increased. One-third (33.8%) of 27,897 intercourse events were condom-protected. Older age (20+ vs. <20 years) and use of hormonal birth control were associated with lower likelihood of condom use at sexual debut (odds ratio [OR] = 0.31, 95% CI:0.13 - 0.74 & OR = 0.38, 95% CI:0.14 - 1.04, respectively, each adjusted for the other variable) Seventy-six women (68%) used condoms at debut. After sexual debut, condom use dropped off rapidly; 50% of those who used a condom at debut had had sex without a condom by the 10th intercourse event. Women who reported partners with previous sex partners were more likely to continue using condoms (hazard ratio = 0.46, 0.23-0.89) than those who reported their partners had no previous partners. Conclusions: In women who delay sexual debut until ≥18 years of age, age and use of hormonal birth control are associated with condom use at first intercourse, though use drops off quickly after debut. Women with sexually experienced partners are more likely to continue using condoms after debut. Continued efforts are necessary to promote condom use among college-aged women.