Background:

Human Papillomavirus (HPV) is associated with multiple cancers and remains the most common sexually transmitted infection in the United States. Each year, approximately seven million U.S. women are newly infected with HPV, and about 17,000 develop new HPV-associated cancers. Three HPV vaccines have been licensed for use in preventing 70% to 90% of HPV strains associated with cervical and other anogenital cancers. Although vaccination provides an opportunity for the primary prevention of HPV associated cancers, uptake of the vaccine has been slow. Sexual minority women (i.e. lesbians and bisexuals, referred to as LB in our study) are at increased risk of acquiring HPV and HPV associated cancers from both female and male sexual partners. However, there is a dearth of research investigating HPV vaccination among sexual minorities. Therefore, the aim of this project was to compare HPV vaccine initiation and completion between straight/heterosexual and lesbian/bisexual women.

Methods:

We aggregated National Health and Nutrition Examination Survey data from 2009-2014 for 2,305 women aged 18 to 34 years. The censored upper age reflects availability of the HPV vaccine, which began in 2006. HPV vaccine initiation was defined as self-reported receipt of at least one dose of the vaccine. HPV vaccine completion was defined as self-reported receipt of all three recommended doses. Self-reported sexual orientation was dichotomized as straight/heterosexual vs. LB. Weighted percentages and multivariable logistic regression models were used to examine differences in HPV vaccine initiation and completion between straight/heterosexual and LB women. Covariates in the adjusted model included age, race, marital status, education, and household income.

Results:

Approximately 11% of respondents identified themselves as LB women. Respondents had initiated the HPV vaccine (22% of heterosexuals vs. 32% of LB women, p=0.0039) significantly more than had completed (15% of heterosexuals vs. 22% of LB women, p=0.0109). After adjusting for covariates, compared to straight/heterosexual women, LB women were 59% more likely to initiate HPV vaccine (aOR=1.59, 95% CI: 1.05-2.42). A one year increase in age was associated with lower odds of initiating HPV vaccination (aOR=0.81, 95% CI: 0.78-0.85). Compared to non-Hispanic White women, Hispanic women were less likely to initiate HPV vaccine (aOR=0.63, 95% CI: 0.42-0.94), and so were women with high school degree or less compared to those with college degree or higher (aOR=0.27, 95% CI: 0.17-0.42). A similar pattern was observed for HPV vaccine completion. In the adjusted model, LB women were 78% more likely to complete the HPV vaccine compared to straight/heterosexual women (aOR=1.78, 95% CI: 1.07-2.96). The same sociodemographic characteristics associated with decreased likelihood of HPV initiation were also significantly associated with HPV completion.

Conclusion:

We found that LB women had higher odds of HPV vaccine initiation and completion compared with straight/heterosexual women, although for both groups the vaccine uptake falls well below the target. Our finding that younger age predicts uptake of this vaccine is particularly promising for the LB population, wherein numerous reports indicate barriers to cancer screening such as access to care and physician's lack of knowledge regarding risk of HPV among LB women. We found LB women more likely to initiate and complete the HPV vaccination protocol, so understanding the drivers of vaccine uptake in the LB population may inform for use among the straight/heterosexual population.

Citation Format: Eric Adjei Boakye, Nosayaba Osazuwa-Peters, Leping Wan, Betelihem B. Tobo, Vy Pham, Mario Schootman, Jane A. McElroy. Disparities in HPV vaccine initiation and completion based on sexual orientation among women in the United States. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr B79.