The association of insulin resistance and obesity with uterine fibroids in non-diabetic populations: a cross-sectional study

To investigate the association between insulin resistance (IR) and obesity and uterine fibroids (UFs) in non-diabetic populations using data from the National Health and Nutrition Examination Survey (NHANES). This cross-sectional study analyzed data from NHANES (1999-2006) and included 867 non-diabetic women aged 20-54 years. IR was assessed using the triglyceride-glucose (TyG) index, TyG-waist-to-height ratio (TyG-WHtR), TyG-body mass index (TyG-BMI), and the homeostasis model assessment of insulin resistance (HOMA-IR). Obesity was assessed by WHtR, weight-adjusted waist index (WWI), waist circumference (WC) and BMI. Logistic regression, restricted cubic spline curves (RCS), subgroup analyses, and interaction tests were performed to evaluate the associations. HOMA-IR index (OR = 1.17, p = 0.004) and BMI (OR = 1.04, p = 0.036) were significantly positively correlated with UFs. Subgroup analyses in those not using female hormones show that among women aged 20-38 years, the association between BMI and UFs was stronger (P < 0.05), while in women aged 39-54 years, HOMA-IR was stronger (P < 0.05). The RCS models indicated significant positive linear associations between HOMA-IR, as well as BMI, and UFs. Our study demonstrates that IR and BMI are independently and positively associated with the presence of UFs in non-diabetic women, indicating that they may be potentially modifiable factors associated with UFs development.