Diabetes Treatment Tied to Lower Uterine Fibroid Incidence in Midlife Women, Study Finds

"Individuals with diabetes experienced a 28% lower occurrence of uterine fibroids, particularly among those taking metformin," the researchers reported. "Our findings provide preliminary evidence suggesting a protective relationship between diabetes and the risk of developing new fibroids."

Uterine fibroids, non-cancerous growths in the uterus, are common among women, particularly during their reproductive years. However, their diagnosis can have profound implications for overall health, especially as women transition into menopause. Susanna D Mitro, Division of Research, Kaiser Permanente Northern California, Pleasanton, CA, USA, and colleagues sought to prospectively investigate the associations between glucose levels, insulin, sex hormone-binding globulin (SHBG), and diabetes with the incidence of fibroid diagnoses during midlife.

For this purpose, participants in the SWAN cohort (n = 2,570) reported fibroid diagnoses at enrollment (1996-1997) and during 13 follow-up visits (1996-2013). At each visit, we measured glucose, insulin, and sex hormone-binding globulin (SHBG) in fasting blood samples and calculated homeostatic model assessment for insulin resistance (HOMA-IR).

Diabetes was classified based on glucose levels, self-reported diabetes, or the use of diabetes medications. Discrete-time survival models were employed to estimate hazard ratios (HR) for the associations between time-varying biomarkers, diabetes, and the occurrence of new fibroid diagnoses, adjusting for demographic factors and healthcare utilization. We also assessed how these associations were influenced by menopausal status.

The study led to the following findings:

• At baseline, 2.7% of participants (n = 70) used diabetes medication.
• Time-varying glucose, insulin, HOMA-IR, and SHBG were not associated with fibroid diagnosis.
• Diabetes was associated with a 28% lower incidence of fibroid diagnosis (adjusted HR 0.72), driven by participants using metformin (adjusted HR 0.49), though precision was limited.
• After stratification by menopausal status, higher HOMA-IR and insulin were associated with a greater incidence of fibroid diagnosis during premenopause but not perimenopause, while the inverse association between diabetes and fibroids was strongest during perimenopause.

"The findings revealed that diabetes is linked to a reduced incidence of uterine fibroids in midlife women undergoing diabetes treatment, particularly with metformin. Additionally, the relationship between diabetes and the risk of uterine fibroids may differ depending on menopausal status," the researchers reported.

Reference:

Mitro, S. D., Waetjen, L. E., Lee, C., Wise, L. A., Zaritsky, E., Harlow, S. D., El Khoudary, S. R., Santoro, N., Solomon, D. H., Thurston, R. C., & Hedderson, M. M. Diabetes and Uterine Fibroid Diagnosis in Midlife: Study of Women's Health Across the Nation (SWAN). The Journal of Clinical Endocrinology & Metabolism. https://doi.org/10.1210/clinem/dgae625