Characteristics of endometriosis : A case-cohort study showing elevated IgG titers against the TSH receptor (TRAb) and mental comorbidity

Objectives: Endometriosis has been associated with a wide range of factors. The disease share immunological features with autoimmune diseases, and the prevalence of both hypo- and hyperthyroidism has been reported to be increased. However, the associations have to be confirmed and the mechanisms explored. The aim of this observational study was to investigate socioeconomic factors, lifestyle habits, and somatic and mental comorbidities in endometriosis compared to the general population. Study design: In all, 172 women with endometriosis completed a study questionnaire and were interviewed regarding socioeconomic factors, lifestyle habits, psychological well-being, and medical history. Bowel symptoms were measured by the Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS). Serum was analyzed for IgG levels of TSH receptor antibodies (TRAb) and anti-thyroid peroxidase (TPO) antibodies. Women from the general population served as controls. Differences were calculated by logistic regression, adjusted for confounders. Results: Alcohol intake, leisure time physical activity, body mass index and asthma were inversely, whereas IBS was positively associated with endometriosis. Hypothyroidism and anti-TPO antibodies did not associate, but elevated TRAb antibody titers were associated with endometriosis (odds ratio (OR): 539.26; 95% confidence interval (CI): 114.29–2544.32 for highest versus lowest tertile; p for trend < 0.001). Impaired psychological well-being (p for trend = 0.003) and current intake of antidepressant medication (OR: 3.54; 95% CI: 1.22–10.28; p = 0.020) associated with endometriosis, and impaired psychological well-being correlated with all gastrointestinal symptoms measured (all p < 0.001). Conclusions: Lifestyle habits and asthma are inversely associated, and IBS and impaired psychological well-being are positively associated with endometriosis. TRAb titers are associated with endometriosis, supporting a link between endometriosis, autoimmunity and thyroid pathophysiology, although overt thyroid diseases do not associate