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Study Examines STI Prevalence, Risk Among Sexually Minority Women

Study Examines STI Prevalence, Risk Among Sexually Minority Women

March 28, 2014 — Summary of "Differences in Sexual Health, Risk Behaviors, and Substance Use Among Women by Sexual Identity: Chicago, 2009-2011," Estrich et al., Sexually Transmitted Diseases, March 2014.

Little literature exists regarding sexual behavior and the risk of sexually transmitted infections (STIs) among women who identify as bisexual or lesbian or have sex with woman, also known as sexual minority women (SMW), even though STIs can be transmitted between female sex partners, according to a study by Cameron Estrich of the American Dental Association and colleagues. STIs among SMW are often undetected because of a lower perceived STI risk in this population, lower use of reproductive health care compared with heterosexual women and primary care providers' "lack of knowledge ... about appropriate screening," the researchers noted.

Despite the lack of detection in many cases, several studies have found higher rates of STIs among SMW than women who only have sex with men. Some research also has indicated an association between "substance use, particularly before or during sex[,] ... and STI diagnosis," suggesting that "elevated rates of substance use may impact sexual behavior and STI outcomes among SMW," according to Estrich and colleagues.

In an attempt to better estimate STI prevalence among SMW and associated risks, the researchers examined "both sexual identity and partner sex to distinguish between risks associated with identification as a sexual minority and the sex of partners."


The researchers conducted a cross-sectional examination of data on 669 women who received reproductive health care services at the Howard Brown Health Center walk-in STI clinic, which "primarily serves lesbian, gay, bisexual, and transgender (LGBT people)." The study included female patients who reported a sexual identity during their first visits to the clinic between January 2009 and December 2011.

The study looked at reports of urogenital gonorrhea (GC) and chlamydia (CT), which are included in the clinic's standard screening protocols. The diagnosis reports were obtained from patients' electronic medical records.

Women's sexual behaviors were measured using risk assessments employed during routine STI screenings. The screenings collected patents' race/ethnicity, age, sexual orientation, STI history, number and sexes of sexual partners for the 90 days prior to the visit, whether sex partners were anonymous, whether they met sex partners on the Internet, and how often they used protective sexual barriers like condoms. The screenings also assessed patients' alcohol and drug use within the past 12 months.

In addition, patients reported their partners' sex; partnership type, such as main or casual; partners' race/ethnicity; relationship type, such as nonmonogamous or monogamous; and whether they participated in unprotected sex of any kind with that partner. Patients also reported whether they or their partners had used alcohol or drugs the last time they had sex.

To analyze the data, the researchers "compared sexual behavior, substance use, and STI diagnoses by sexual identity."


Out of the 669 women in the study, 9.3% identified themselves as lesbian, 15.3% said they were bisexual and 75.4% said they were heterosexual. The study found no significant differences in sexual identity across racial/ethnic groups.

According to the study, bisexual woman were much more likely (68%) to report having more than one recent sexual partner, compared with heterosexual (43%) or lesbian women (42%).

The researchers noted a "discordance between sexual identity and reported sex partner sex," with "32.8% of lesbians report[ing] male partners in the last 90 days, and 2.5% of heterosexuals report[ing] female partners." They also found that bisexual women were about twice as likely as heterosexual women to have an anonymous partner and that bisexual women were less likely than both heterosexual and lesbian women to report that their most recent sexual partner was their main or monogamous partner.

In examining substance use, the researchers found that SMW were two times more likely than heterosexual women to have used drugs in the past 12 months. Bisexual women were most likely to have used drugs overall, and their sex partners were "significantly more" likely to have used substances at their last instance of sex, the researchers wrote. Meanwhile, reported alcohol use within the past 12 months was high among all groups, although self and partner alcohol use at the last instance of sex was significantly higher among bisexual and heterosexual women than it was among lesbian women.

Almost all of the women in the study reported having oral, anal or vaginal sex within the 90 days prior to the visit, with no notable differences by sexual identity. Both bisexual and lesbian women were statistically similar in their reports of vaginal sex and were both less likely to have reported having vaginal sex than heterosexual women. According to the study, reports of consistent condom use during vaginal sex were "low and did not vary by sexual identity." Bisexual women were more likely to report having anal sex than lesbian or heterosexual women, and they also had the highest rate of condom use among those who reported having anal sex.

On STI prevalence, the study found 1.5% of women had laboratory-confirmed GC and 5.2% had lab-confirmed CT. GC and CT rates were significantly higher among women ages 25 or younger compared with women older than age 25. Neither GC nor CT rates varied by sexual identity, but all women with GC or CT diagnoses had reported recent male sex partners.

According to the study, only partner sex and age were significantly associated with STI diagnosis. In addition, the study found variances in self-reported STI history, with 43.4% of bisexuals and 42.6% of heterosexuals reporting having been previously diagnosed with an STI, while 18.3% of lesbians had reported a previous diagnosis. The study also showed that lesbian women were significantly less likely to be diagnosed with an STI compared with both heterosexual and bisexual women.

Discussion and Conclusions

Because "sexual identity was not as powerful a predictor of STI risk as sex of partners," it is important to collect "patient information on both sexual identity and sex partners ... to fully understand risks," the researchers wrote, although they noted that "eliciting accurate disclosure can be difficult, as SMW may anticipate heterosexist or homophobic treatment from providers."

To address this issue, the researchers suggested that providers receive diversity training. They added, "Knowledge of patients' sexual identity is helpful not only in providing culturally competent care but also in correctly identifying risks associated with social prejudice and stress, such as substance use and mental health outcomes."

They also highlighted the "significant differences in behaviors and STI diagnoses between lesbian and bisexual women, suggesting that combining SMW into a single category may mask important differences in behavior and disease prevalence." Further, the "discordance between sexual orientation and sex of partners suggests that" all women who have sex with men should be screened for STIs, the researchers wrote.