Risk of Breast Cancer Mortality Among Women Cohabiting with Same Sex Partners: Findings from the National Health Interview Survey, 1997–2003

Abstract

Lesbians and bisexual women are more likely than other women to evidence a unique mix of common breast cancer risk factors. It is not known if this results in greater breast cancer mortality risk. We investigate possible sexual orientation-related differences in risk for fatal breast cancer in a large representative U.S. sample of married and cohabiting women. Between 1997 and 2003, the National Health Interview Survey (NHIS) interviewed married or cohabiting female participants, aged 18-80 years inclusively, who reported either a male (n=136,174) or female (n=693) coresidential relationship partner. These records are linked to the National Death Index to provide information on mortality status as of December 31, 2006. Employing these data, we estimated the age-adjusted relative risk (RR) and its 95% confidence interval (CI) for mortality attributed to breast cancer using a Cox proportional hazard model. Women in same-sex couples, compared to women in different-sex relationships, had greater age-adjusted risk for fatal breast cancer (RR=3.2, CI 1.01-10.21) but did not differ in their overall risk for mortality. Our findings provide tentative support that sexual orientation is differentially linked to risk of fatal breast cancer. These findings underscore the need to investigate further breast cancer morbidity and mortality risk among women with minority sexual orientation.