STIs among young adult females in the US: Does sexual identity make a difference?

Few studies have assessed risk for sexually transmitted infections (STIs) among young adult women by sexual identity. We analyzed Wave IV (2007/8) restricted data from the National Longitudinal Study of Adolescent Health (Add Health), a nationally representative sample of individuals who were enrolled in grades 7 through 12 in 1994/5. Respondents were 24 to 34 years old in 2007/8. Analyses were restricted to female respondents assigned a probability weight, who had at least one sex partner in their lifetime, and reported their sexual identity (n= 7,310). We employed multivariate logistic regression to examine the association between sexual identity and risk of STI diagnosis (past year), after adjustment for socio-demographics (age, race/ethnicity, education, income, employment, marital status), sexual behaviors (oral, anal and vaginal sex; number of lifetime sex partners; gender of sex partners; ever physically forced to have sex), and other behaviors (cigarette smoking, binge drinking, illicit drug use, routine doctor check-up). Overall, 13% of young adult women reported an STI in the past year. Sexual identity was significantly associated with an STI diagnosis; 12.0% of straight women, 17.8% of mostly straight women, 19.1% of bisexual women, and 7.1% of mostly gay/gay women reported an STI diagnosis in the past year. In multivariate analyses, young adult women who were non-Hispanic Black, unmarried, cohabitating, had three or more sex partners during their lifetime, and had both male and female sex partners during their lifetime were at increased odds of reporting an STI diagnosis in the past year. Sexual health programs targeting young adult women, regardless of sexual identity, must focus on behavioral risks associated with STIs. Additional research is needed to understand increased risk among young adult women who are sexually active with both sexes.