County-Level Association of Sexual Minority Density with Breast Cancer Incidence: Results from an Ecological Study

摘要

To test the hypothesis that breast cancer incidence rates are higher in areas where more lesbian women reside. In this secondary analysis, we are linking Surveillance, Epidemiology, and End Results (SEER) breast cancer data from 1996 to 2004 with Census 2000 data. From the Census 2000 data on female same-sex partnered households, we derive a measure of sexual minority women density (SMWD) for each of the 215 counties covered by SEER 12. We test the association of SMWD with breast cancer incidence using multivariable Poisson regression models that control for age, race, and socioeconomic status. We find a significant positive association between SMWD and breast cancer incidence. The incidence rate ratio indicates that a one-unit increase in SMWD is associated with a 13% increase in breast cancers. Our findings suggest that lesbian women may be overrepresented among women with breast cancer. Future studies are needed, relating breast cancer incidence to individual sexual orientation, to confirm our findings.