Sexual behavior and risk of diagnosis with multiple sclerosis: A retrospective case–control study

Adolescence is a critical window during which psychosocial factors have significant effects on the lifetime risk of multiple sclerosis (MS). Sexual behavior is relevant early in adulthood and has not been described in its relationship to MS. Using a retrospective secondary analysis of cross-sectional data in the TriNetX database, we investigated the connection between orientation of sexual behavior and MS risk. We identified 13,595 males and 9,589 females with same-sex behavior and 64,409 males and 137,450 females with opposite-sex behavior. Cohorts were balanced on age, race, and ethnicity. Males engaging in same-sex behavior had a 2.80-fold higher risk of MS diagnosis (95% confidence interval [CI]: 1.66 – 4.73), and females engaging in same-sex behavior had a 2.30-fold higher risk of MS diagnosis (95% CI: 1.65 – 3.20). Our findings thus advance the understanding of MS risk in the context of social determinants of health.