Sex Modifies the Effect of Genetic Risk Scores for Polycystic Ovary Syndrome on Metabolic Phenotypes

Abstract

Females with polycystic ovary syndrome (PCOS), the most common endocrine disorder in women, have an increased risk of developing metabolic disorders such as insulin resistance, obesity, and type 2 diabetes (T2D). Furthermore, while only diagnosable in females, males with a family history of PCOS can also exhibit a poor cardiometabolic profile. Therefore, we aimed to elucidate the role of sex in the relationship between PCOS and its comorbidities by conducting bidirectional genetic risk score analyses in both sexes. We conducted a phenome-wide association study (PheWAS) using PCOS polygenic risk scores (PCOSPRS) to understand the pleiotropic effects of PCOS genetic liability across 1,380 medical conditions in females and males recorded in the Vanderbilt University Medical Center electronic health record (EHR) database. After adjusting for age and genetic ancestry, we found that European descent males with higher PCOSPRS were significantly more likely to develop cardiovascular diseases than females at the same level of genetic risk, while females had a higher odds of developing T2D. Based on observed significant associations, we tested the relationship between PRS for comorbid conditions (e.g., T2D, body mass index, hypertension, etc.) and found that only PRS generated for BMI and T2D were associated with a PCOS diagnosis. We then further decomposed the T2DPRS association with PCOS by adjusting the model for measured BMI and BMIresidual (enriched for the environmental contribution to BMI). Results demonstrated that genetically regulated BMI primarily accounted for the relationship between T2DPRS and PCOS. This was further supported in a mediation analysis, which only revealed clinical BMI measurements, but not BMIresidual, as a strong mediator for both sexes. Overall, our findings show that the genetic architecture of PCOS has distinct metabolic sex differences, but these associations are only apparent when PCOSPRS is explicitly modeled. It is possible that these pathways are less explained by the direct genetic risk of metabolic traits than they are by the risk factors shared between them, which can be influenced by biological variables such as sex.