Application of the Rosner-Wei risk-prediction model to estimate sexual orientation patterns in colon cancer risk in a prospective cohort of US women

Abstract

Purpose: We examined whether lesbian and bisexual women may be at greater risk of colon cancer (CC) than heterosexual women.

Methods: Working with a large cohort of US women ages 25-64 years, we analyzed 20 years of prospective data to estimate CC incidence, based on known risk factors by applying the Rosner-Wei CC risk-prediction model. Comparing to heterosexual women, we calculated for lesbian and bisexual women the predicted 1-year incidence rate (IR) per 100,000 person-years and estimated incidence rate ratios (IRR) and 95 % confidence intervals (CI), based on each woman's comprehensive risk factor profile.

Results: Analyses included 1,373,817 person-years of data from 66,257 women. For each sexual orientation group, mean predicted 1-year CC IR per 100,000 person-years was slightly over 12 cases for each of the sexual orientation groups. After controlling for confounders in fully adjusted models and compared with heterosexuals, no significant differences in IRR were observed for lesbians (IRR 1.01; 95 % CI 0.99, 1.04) or bisexuals (IRR 1.01; 95 % CI 0.98, 1.04).

Conclusions: CC risk is similar across all sexual orientation subgroups, with all groups comparably affected. Health professionals must ensure that prevention, screening, and treatment programs are adequately reaching each of these communities.