Fig. 1

Flowchart of eligible participants selection. Flowchart of participant selection from the NHANES 1999–2006 dataset. A total of 41,474 participants were initially considered. After excluding participants based on gender, age, and missing covariate data, 11,799 participants remained. Further exclusions were made for missing endometriosis or NHHR data, resulting in 4,990 eligible participants, with 354 participants diagnosed with endometriosis and 4,636 participants without endometriosis