Association of body mass index with early age at diagnosis of endometrial intraepithelial neoplasia.

Objective: Elevated body mass index (BMI) is a risk factor for endometrioid endometrial cancer and its precursor, endometrial intraepithelial neoplasia (EIN). Our objective was to describe the association between BMI and age at EIN diagnosis.

Methods: We conducted a retrospective study of patients diagnosed with EIN from 2010 to 2020 at a large academic medical center. Patient characteristics were stratified by menopausal status and compared using a chi-square or t-test. We used linear regression to determine the parameter estimate (β) and 95% confidence interval for the association between BMI and age at diagnosis.

Results: We identified 513 patients with EIN; 503 (98%) had complete medical records. Premenopausal patients were more likely to be nulliparous and to have polycystic ovary syndrome than postmenopausal patients (both p ≤ 0.001). Postmenopausal patients were more likely to have hypertension, type 2 diabetes, and hyperlipidemia (all p ≤ 0.02). There was a significant linear association between BMI and age at diagnosis in premenopausal patients (β = -0.19 (95% CI: -0.27, -0.10). In premenopausal patients, for every 1-unit increase in BMI, age at diagnosis decreased by 0.19 years. No association was observed in postmenopausal patients.

Conclusions: In a large cohort of patients with EIN, increasing BMI was associated with an earlier age at diagnosis in premenopausal patients. This data suggests consideration of endometrial sampling in younger patients with known risk factors for excess estrogen exposure.