Correlates of Lesbian Sexual Orientation and the Risk of Breast Cancer

Abstract

Objectives: This study describes an attempt to estimate the relative risk of breast cancer for lesbians from existing case–control data, using surrogate correlates of sexual orientation. Design: Three different theoretical correlates of sexual orientation were constructed from data available from a population-based case–control study. Setting: Participants were 747 invasive breast cancer cases and 961 control women aged 21–45 years in three counties in western Washington State. Measurements: The correlates used were: Measure 1, no male sexual partners ever; Measure 2, never married and not currently using contraception; Measure 3, not currently married and not using contraception. Results: The relative risk of breast cancer for lesbians as compared to women who were not lesbians for each of the three surrogate measures was estimated to be 1.74 [95% confidence interval (CI): 0.62–4.91], 1.62 (95% CI: 1.04–2.52), and 1.13 (95% CI: 0.84–1.51), respectively. The elevated risks in all cases were largely, but not entirely, explained by suspected differences between lesbians and nonlesbians in demographic, social, and reproductive factors. Conclusions: This hypothesis-generating study suggests that lesbians may be at an increased risk of breast cancer as compared to nonlesbians. In light of the documented barriers to health care access for lesbians, efforts to educate lesbians and provide culturally appropriate preventive care and screening services should be considered.