Lijie Liu,1,* Chuan Shao,2,* Lujia Li,1 Nan Wu2 

1Department of Health Care, People’s Liberation Army Navy 971 Hospital, Qingdao, 266071, People’s Republic of China; 2Department of Neurosurgery, Chongqing General Hospital, Chongqing University, Chongqing, 401147, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Lujia Li, Department of Health Care, People’s Liberation Army Navy 971 Hospital, Shandong Road, Qingdao, 266071, People’s Republic of China, Email li_lujia2025@yeah.net Nan Wu, Department of Neurosurgery, Chongqing General Hospital, Chongqing University, 118 Xingguang Boulevard, Liang Jiang New Area, Chongqing, 401147, People’s Republic of China, Tel/Fax +86-23-63390700, Email wunan@cqu.edu.cn

Objective: Less is known about the link between mortality and endometriosis, an often chronic, inflammatory gynecologic condition. We assessed the association between endometriosis and all-cause and cause-specific mortality using a retrospective cohort study design based on data from the National Health and Nutrition Examination Survey (NHANES) 1999– 2006.
Materials and Methods: Both crude and multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for endometriosis and age at endometriosis with all-cause mortality were estimated using weighted Cox proportional hazards regression. Moreover, we also performed an exploratory analysis assessing the relationship between endometriosis and mortality from cancer and cardiovascular disease (CVD).
Results: Between 1999 and 2006, a cohort of 5552 women aged 20 to 54 years was studied, representing a weighted population of approximately 66.07 million. Over a median follow-up duration of 16.75 years, 290 participants died from various causes, which extrapolates to an estimated 3,411,632 female deaths in the broader population. A non-significant association was identified between endometriosis and all-cause mortality (HR  1.51, 95% CI: 0.97– 2.34, P = 0.066), cancer (HR 1.45, 95% CI: 0.76– 2.78, P = 0.260), or CVD (HR 1.75, 95% CI: 0.65– 4.73, P = 0.271) mortality. When accounting for the age at endometriosis was diagnosed, the association was significant only among women diagnosed at age ≤ 30 years (HR = 1.87, 95% CI: 1.15– 3.03, P = 0.011 for all-cause mortality; HR = 4.37, 95% CI: 1.54– 12.36, P = 0.005 for CVD mortality) and was not significant for those diagnosed after age 30 years.
Conclusion: In conclusion, women diagnosed with endometriosis at a younger age may be associated with an increased risk of mortality.

Keywords: endometriosis, mortality, cohort, NHANES, risk