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A research team led by Dr. Rinku Majumder from LSU Health New Orleans has published a groundbreaking study in the Journal of Clinical Investigation showing how obesity and estrogen-based medications (including hormonal therapies and oral contraceptives) act together to dramatically increase the thrombotic risk in premenopausal women.

The study helps explain how obesity and estrogen collaborate and amplify thrombotic risk and offers new insight that could improve care for people who already face higher thrombotic risk, including patients with cancer.

Researchers discovered that the risk of thrombosis increases dramatically in premenopausal women with obesity who are taking estrogen-based medications, due to a substantial reduction in Protein S, a natural anticoagulant that helps prevent harmful blood clots. When Protein S levels fall, thrombotic risk rises.

Why this matters for cancer care

Hypercoagulability, or formation of blood clots, is a serious concern for patients undergoing cancer treatment. The findings of this study could be extended for cancer patients who also have obesity or use estrogen-based medications (including hormone therapy or some birth control pills) and therefore live with heightened thrombotic risk. Understanding these added risks can help doctors better monitor, prevent, and treat vulnerable patients.

"This study gives us a clearer picture of how everyday factors like weight and hormone use can interact in ways that have real health consequences," said Dr. Rinku Majumder, professor of Interdisciplinary Oncology, LSU Health New Orleans. "For cancer patients especially, having this knowledge helps us protect them more effectively."

This study highlights the need to address the obesity epidemic in Louisiana and in the US as a whole. Obesity increases the risk of multiple cancers, and this work makes clear a mechanism whereby it also increases the risk of thrombotic episodes in patients taking oral contraceptives or hormone-replacement therapy for menopausal symptoms.

The work was led by scientists in the LSU Health New Orleans Department of Interdisciplinary Oncology, in collaboration with the Department of Genetics, The LSU LCMC Health Cancer Center, and national and international partners.

Publication details

Mohammad A. Mohammad et al, Estrogen and obesity synergistically suppress protein S via HIF1α, enhancing thrombosis potential, Journal of Clinical Investigation (2025). DOI: 10.1172/jci193976

Journal information: Journal of Clinical Investigation

Citation: Researchers link obesity, estrogen use, and increased blood-clotting risk (2026, January 22) retrieved 22 January 2026 from https://medicalxpress.com/news/2026-01-link-obesity-estrogen-blood-clotting.html

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