Key takeaways:
- Higher remnant cholesterol levels were significantly associated with increased odds of endometriosis in a nationally representative US cohort.
- Each 1 mg/dL increase in remnant cholesterol corresponded to an approximate 2% rise in endometriosis prevalence.
- The association remained significant after adjustment for demographic, socioeconomic, metabolic, and lifestyle factors.
- Patients with endometriosis had higher total cholesterol and remnant cholesterol levels compared with controls.
- Findings suggest lipid metabolism and systemic inflammation may contribute to endometriosis pathophysiology beyond cardiovascular disease.
Increased remnant cholesterol (RC) is linked to greater odds of endometriosis, according to a recent study published in the International Journal of Women’s Health.1
The precise causes of endometriosis remain unclear, but recent data has indicated oxidative stress as a potential source.2 This process may trigger a widespread inflammatory response that leads to further growth and implantation of ectopic endometrial tissue.
“While a growing body of evidence links RC to cardiovascular diseases, its role in endometriosis remains largely unexplored,” wrote investigators.1
Participant selection and laboratory assessment
The trial was conducted to address this research gap. Data about RC levels and endometriosis incidence were obtained from the NHANES database, a health and nutrition survey conducted by the CDC. Survey participants between 1999 and 2006, aged 20 to 54 years, were included in the current analysis.
Exclusion criteria included being male, outside the specified age range, and lacking data about cholesterol or endometriosis. After fasting for 8 hours, participants provided morning blood sample,s which were assessed for RC, alongside triglyceride and total cholesterol (TC).
The heparin-manganese precipitation method was used to evaluate serum high-density lipoprotein cholesterol (HDL-C) levels. Endometriosis was reported as the primary outcome, determined based on responses to the “rhq360” questionnaire.
Racial and lipid profile differences
Patients responding positively to a question asking whether they had been diagnosed with endometriosis were defined as cases, while those who responded negatively were defined as controls. Covariates included smoking habits, hypertension, diabetes, drinking status, body mass index, HDL-C, low-density lipoprotein cholesterol, and contraceptive pill use.
A total of 2187 participants were included in the final analysis, with 7.82% of them diagnosed with endometriosis. These patients had a mean age of 40.41 years, vs 37.31 years in non-endometriosis patients. Additionally, rates of smoking were 58.2% vs 40%, respectively.
Investigators also highlighted racial disparities, with 83.3% of endometriosis patients being non-Hispanic White women vs 69% without endometriosis. In Mexican American women, these rates were 1.3% vs 8.4%, respectively. The endometriosis group also presented with significantly increased TC and RC levels.
Association between remnant cholesterol and endometriosis
A significant association was found between RC levels and the prevalence of endometriosis. Specifically, each 1 mg/dL rise in RC was linked to a 2.3% increase in the rate of endometriosis, with an unadjusted odds ratio (OR) of 1.022. When adjusting for age, ethnicity, education level, and marital status, the OR remained significant at 1.022.
When further adjusting for poverty income ratio, smoking habits, hypertension, diabetes, drinking status, and other covariates, the OR was 1.023. A significantly higher prevalence of endometriosis was reported in patients from the third tertile of RC vs the lowest tertile, with an adjusted OR of 1.833. These associations did not change across subgroups.
Overall, the results indicated an inverse correlation between RC levels and endometriosis rates. Investigators concluded that this data highlights the importance of considering lipid metabolism as a possible source of systemic inflammatory conditions unrelated to cardiovascular health.
“Future studies should focus on longitudinal designs to clarify the temporal relationship between RC levels and endometriosis and to explore the underlying biological mechanisms that may drive this association,” wrote investigators.
References
- Su L, Wang X, Zhang J, Xu R, Ren Y, Wang S. Association between remnant cholesterol and endometriosis findings from NHANES 1999–2006. International Journal of Women’s Health. 2025. doi:10.2147/IJWH.S568397
- Scutiero G, Iannone P, Bernardi G, et al. Oxidative stress and endometriosis: a systematic review of the literature. Oxid Med Cell Longev. 2017. doi:10.1155/2017/7265238
