Endometriosis and risk of depression among oral contraceptive users: a pooled analysis of cohort studies from 13 countries.

Study Question: Does endometriosis affect the mental health of women using oral contraceptives?

Summary Answer: Among oral contraceptive users, women with endometriosis have a higher risk of depression compared to those without endometriosis, although the absolute risk increase is small.

What Is Known Already: Previous studies have suggested a potential link between endometriosis and mental health issues, but the impact of endometriosis on depression among oral contraceptive users remains unclear.

Study Design, Size, Duration: A secondary pooled cohort study utilizing data from two longitudinal patient-centric studies (INAS-VIPOS and PRO-E2) was conducted across 11 European countries, Colombia and Australia. The study included 93 541 women newly prescribed oral contraceptives, with or without endometriosis, and without a self-reported history of depression.

Participants/materials, Setting, Methods: Participant's mental health was captured using self-administered questionnaires at baseline and every 6-12 months thereafter, asking about any newly occurred episodes of depression. Incidence rates (IRs) of self-reported depression were calculated per 10 000 woman-years. Absolute risk difference (ARD) and number needed to harm (NNH) were calculated with 95% CIs. The association between endometriosis and self-reported depression was estimated through crude and adjusted hazard ratios (HRs) with 95% CI, using stabilized inverse probability of treatment weighting (IPTW).

Main Results And The Role Of Chance: Of the included 93 541 women, 21 090 had endometriosis (49 541 woman-years) and 72 451 had no endometriosis (137 137 woman-years.) Of those with endometriosis, 308 (1.5%) reported an episode of depression (IR: 62.2/10 000, 95% CI: 55.4-69.5) compared to 535 (0.7%) of women without endometriosis (IR 39.0/10 000, 95% CI: 35.8-42.5). The ARD and NNH were 23.2 per 10 000 (95% CI: 15.2-30.9) and 431 (95% CI: 323.7-657.0) respectively. The HR of depression in women with endometriosis was 1.85 (95% CI: 1.60-2.13) using stabilized IPTW to control for age, BMI, smoking, education, and age at menarche. Subgroup and sensitivity analyses showed similar results.

Limitations, Reasons For Caution: While efforts were made to control for confounding factors, residual confounding may still exist. Additionally, the results can only be generalized to users of oral contraceptives.

Wider Implications Of The Findings: These results highlight the importance of considering the mental health implications of endometriosis among women using oral contraceptives. Further research is needed to explore additional contributing factors and potential interventions.

Study Funding/competing Interest(s): No funding was received for this study. No competing interests apply for this research.

Trial Registration Number: N/A.