Association Between Dietary Selenium Intake and Endometriosis Risk: A Cross-Sectional Analysis

Jia-Jie Guo^1,2,3,4,5Rui-Xuan Li^1,2,3,4,6Wen-Li Shang^1,2,3,4,6Ya-Fang Zheng^1,2,3,4,7Guo-Yi Zhu^1,2,3,4,8Zhou- Chang Shu^1,2,3,4,9Gui-Chao Liu^1,2,3,4,6Hong-Biao Ou^1,10,2,3,4Jiaying Li^1,2,3,4,6Xu-Guang Guo^11,12,13,14*Li-Hong Lin^1,15,2,3,4*

• ¹Department of Obstetrics and Gynecology, Center for Reproductive Medicine; The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
• ²Guangdong Provincial Key Laboratory of Major Obstetric Diseases; The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
• ³Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology; The Third Affiliated Hospital, Guangzhou Medical University., Guangzhou, China
• ⁴Guangdong-Hong Kong-Macao Greater Bay Area Higher Education Joint Laboratory of Maternal-Fetal Medicine, The Third Affiliated Hospital, Guangzhou Medical University,, Guangzhou, China
• ⁵The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
• ⁶School of Health Management, Guangzhou Medical University, Guangzhou, Guangdong Province, China
• ⁷7Department of Clinical Medicine, The Third School of Clinical Medicine, Guangzhou Medical University, Guangzhou, 511436, China
• ⁸Department of Clinical Medicine, The Third School of Clinical Medicine, Guangzhou Medical University, Guangzhou, 511436, China
• ⁹School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, Guangdong Province, China
• ¹⁰Second Clinical School, Guangzhou Medical University, Guangzhou, China
• ¹¹Institute of Gerontology, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China
• ¹²State Key Laboratory of Respiratory Disease, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China
• ¹³Collaborative Innovation Center for Civil Affairs of Guangzhou, Guangzhou, China
• ¹⁴Department of Clinical Laboratory Medicine, Guangzhou Geriatric Hospital, Guangzhou Medical University, Guangzhou, China
• ¹⁵The Third School of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China

Background: Endometriosis (EMs) is a common chronic inflammatory disorder with estrogen dependency, and its causes and progression are not fully understood. With limited treatment options available, the dietary impact on EMs incidence has gained research interest. This study explores the link between dietary selenium intake and EMs risk, noting selenium's key antioxidant role in reducing oxidative stress and inflammation, and its potential to modulate immune responses, offering protective effects.The study included 39,352 participants from National Health and Nutrition Examination Survey (NHANES) data (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006). We excluded individuals with missing data on dietary selenium intake or EMs status, pregnant women, and individuals with missing basic covariate data or suspected erroneous dietary selenium intake values. After these exclusions, a final cohort of 3,876 participants was included for detailed analysis. This cohort was stratified into two groups: 3566 individuals without a diagnosis of endometriosis and 310 individuals diagnosed with EMs. The relationship between EMs and dietary selenium intake was examined using a suite of statistical methodologies, including multivariate logistic regression to control for confounding variables, smooth curve fitting, threshold effect analysis and subgroup analysis.Results: After adjusting for multiple covariates, the multivariate logistic regression model indicated a negative correlation between dietary selenium intake and the risk of developing EMs. In the highest dietary selenium intake group, the adjusted model II revealed a reduction in the risk of EMs by approximately 34.1% (OR = 0.659, 95% CI: 0.449, 0.967). The subgroup analysis revealed a negative relationship between quartiles of selenium intake and the risk of endometriosis in participants aged fifty years and older, in non-Hispanic white participants, in participants with PIR >=1.3 and <3.5, in participants with a high school education level or under, in participants who get married or live with a partner, in participants who have never drunk, and in participants who smoke currently.Our findings suggest a negative correlation between dietary selenium intake and endometriosis risk. However, potential confounding factors may influence this association. Given the limitations of this cross-sectional study, such as reliance on self-reported data, further prospective research is required to confirm causality and explore underlying mechanisms.