Diabetes Treatment May Lower Incidence of Uterine Fibroids

TOPLINE:

Diabetes is associated with a lower incidence of uterine fibroids in midlife women receiving diabetes treatment, especially metformin. The association between diabetes and the risk for uterine fibroids may vary based on menopausal status.

METHODOLOGY:

• Previous studies have provided inconsistent evidence regarding associations between the risk for uterine fibroids and markers of cardiometabolic health, such as fasting insulin, fasting glucose, and diabetes.
• Researchers conducted a prospective cohort study to examine the association of fasting levels of cardiometabolic blood biomarkers, diabetes, and diabetes treatment with the incidence of new fibroid diagnoses in midlife women.
• They included participants from the Study of Women’s Health Across the Nation cohort who reported fibroid diagnoses at enrollment and during 13 follow-up visits.
• At all visits, levels of glucose, insulin, and sex hormone–binding globulin (SHBG) were measured in fasting blood samples, and homeostatic model assessment for insulin resistance (HOMA-IR) was calculated.
• Discrete-time survival models were used to estimate the hazard ratios (HRs) for the associations of biomarkers and diabetes with fibroid diagnoses, adjusted for demographics and healthcare utilization.

TAKEAWAY:

• Researchers identified 2570 eligible women (median age, 45 years; 45% perimenopausal women), among whom approximately 3% had diabetes at baseline.
• Diabetes was associated with a 28% lower incidence of new fibroid diagnosis (adjusted HR, 0.72).
• This association was particularly strong among participants with treated diabetes, especially those on metformin, who had a 51% lower incidence of self-reported fibroids than those without diabetes. The estimates, however, had wide CIs suggesting uncertainty.
• Time-varying HOMA-IR and SHBG, insulin, and glucose levels were not significantly associated with the new fibroid diagnosis.
• When stratified by menopausal status, higher HOMA-IR and insulin levels were associated with a greater incidence of fibroid diagnosis during premenopause but not during perimenopause.

IN PRACTICE:

“Our findings contribute to preliminary evidence indicating a protective association between diabetes and risk of incident fibroids,” the authors wrote.

SOURCE:

The study was led by Susanna D. Mitro, Division of Research, Kaiser Permanente, Pleasanton, California, and was published online in The Journal of Clinical Endocrinology & Metabolism.

LIMITATIONS:

The study relied on self-reported fibroid diagnoses, which may result in the misclassification of cases. The sample size of participants with diabetes was small, which resulted in reduced precision and confidence in the findings. The baseline eligibility criteria (midlife participants with an intact uterus and no history of fibroid incidence) may have limited the generalizability of the findings to the wider population at risk for fibroids.

DISCLOSURES:

This study was supported by the National Institutes of Health (NIH), through the National Institute on Aging, the National Institute of Nursing Research, and the NIH Office of Research on Women’s Health. One author reported being a consultant and advisor for various pharmaceutical companies. Two other authors reported receiving salary support and royalties from various pharmaceutical companies and organizations.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.