Abstract P1174: Endometriosis diagnosis, staging, and typology in relation to inflammatory cytokines

Endometriosis, affecting 11% of reproductive-aged persons, is characterized by ectopic endometrial tissue and chronic inflammation. Prior research suggests those with endometriosis have higher cardiovascular disease risk, but mechanisms remain elusive. The objective of this study is to assess whether endometriosis diagnosis, staging, and typology (superficial endometriosis (SE), ovarian endometriomas (OE), and deep infiltrating endometriosis (DE)) are associated with serum interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF-) concentrations.

The study analyzed data from 395 premenopausal persons in Utah undergoing gynecologic laparoscopy who participated in the NICHD ENDO study (2007–2009). Post-operative reports determined endometriosis typology (SE, OE, DE) and staging (minimal, mild, moderate, severe) using Revised American Society for Reproductive Medicine classification. Elevated serum cytokine concentrations were defined as IL-6 ≥2pg/mL, IL-8 ≥3pg/mL, and TNF- ≥7.5pg/mL. Generalized linear models generated adjusted prevalence ratios (aPR) 95% CI controlling for age, BMI, marital status, race/ethnicity, and serum cotinine.

Participants were on average 32 years (SD=7) at time of gynecologic laparoscopy/laparotomy, non-Hispanic white (79%), married (71%), mean BMI 28 (SD=8) and non-smokers (83% serum cotinine <10ng/mL). Forty-two percent (n=166) were diagnosed with incident endometriosis. We found no differences among those with, compared to without, endometriosis and elevated IL-6, 12% vs 10%, aPR: 1.01 (0.97, 1.10), IL-8, 5% vs 8%, aPR: 0.99 (0.94, 1.04); and TNF, 16% vs 13%, aPR: 1.00 (0.96, 1.04). While there were no statistically significant associations between endometriosis staging or typology and cytokines, those with moderate to severe endometriosis had nonsignificant lower IL-6 and IL-8 (aPR: 0.61 [0.15, 2.52] and aPR: 0.74 [0.17, 3.20]) but higher TNF- (aPR: 1.27 [0.56, 2.84]), compared to no endometriosis. Individuals with OE and DE had nonsignificant trends of IL-6 and Il-8 (aPR: 0.86 [0.11, 2.52] and aPR: 0.93 [0.14, 6.43]) but higher TNF- (aPR: 1.93 [0.77, 4.84]).

In summary, this study found no clear correlation between endometriosis diagnosis, staging, typology and inflammatory markers IL-6, IL-8, and TNF-. Whether endometriosis severity or typology is associated with TNF- should be explored in future studies with adequate power and more representative samples.