The burden of endometriosis on quality of life in Danish women: an analysis of the Danish Blood Donor Study.

Background: Endometriosis is a complex condition with a wide range of comorbidities. It is widely underdiagnosed, with a diagnostic delay of 4 to 10 years, potentially leading to worsened disease progression and a higher burden of comorbidities affecting quality of life. Understanding the link between endometriosis and its comorbidities is essential for improving early detection of the disease.

Methods: We analysed data from 953 women with a clinical diagnosis of endometriosis and 23,652 age-matched female controls enrolled in the Danish Blood Donor Study, using a case-control design. Participants completed one to four questionnaires covering a wide range of potential comorbidities; genetic data were available for a subset of participants. First, we compared the potential comorbidities between women with endometriosis and controls. Next, we investigated whether a polygenic score (PGS) for endometriosis was associated with those comorbidities. Lastly, we investigated whether women with a high genetic burden of endometriosis (highest PGS decile) experienced similar comorbidities to those diagnosed with endometriosis.

Results: Women with endometriosis experienced challenges in conception, gastrointestinal symptoms, and disturbed sleep patterns, compared to age-matched controls. The endometriosis PGS showed to be a predictor for endometriosis (OR per unit PGS = 1.43, 95% CI = 1.32-1.55). Gastrointestinal symptoms were also nominally associated with the endometriosis PGS, suggesting shared genetic pathways. Women without a diagnosis of endometriosis but with a high genetic burden of endometriosis did not suffer from the same wide range of comorbidities as women diagnosed with endometriosis.

Conclusions: Our findings highlight the complex genetic and clinical relationships between endometriosis and its comorbidities, emphasizing the need for future research investigating potential endometriosis subtypes.