KEY TAKEAWAYS: Obesity and estrogen use sharply increase blood-clot risk in premenopausal women. Protein S reduction identified as a key mechanism for elevated thrombotic risk. Findings are particularly relevant for cancer patients with heightened clotting risks. Study led by LSU Health New Or leans, published in Journal of Clinical Investigation.   Researchers at LSU Health New Orleans have identified a critical interaction between obesity and estrogen-based medications that significantly increases the risk of dangerous blood clots in premenopausal women. The study, led by Dr. Rinku Majumder, was published in the Journal of Clinical Investigation. The research found that women with obesity who use estrogen-containing therapies—including oral contraceptives and hormone replacement treatments—experience a sharp drop in Protein S, a natural anticoagulant that helps prevent harmful clots. Reduced Protein S levels amplify thrombotic risk, providing a biological explanation for the elevated clotting seen in this population. “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. Majumder, professor of Interdisciplinary Oncology at LSU Health New Orleans. “For cancer patients especially, having this knowledge helps us protect them more effectively.” The findings carry particular significance for cancer care. Patients undergoing treatment already face heightened risks of hypercoagulability, or excessive blood clot formation. Obesity and estrogen use can further elevate this risk, suggesting that clinicians may need to adjust monitoring and preventative strategies for vulnerable patients. The study also underscores broader public health concerns, including the obesity epidemic in Louisiana and across the United States. Obesity is linked to multiple cancers, and this research reveals a mechanism by which it may also increase thrombotic events in women taking estrogen-based medications. The project was led by LSU Health New Orleans’ Department of Interdisciplinary Oncology, in partnership with the Department of Genetics, LSU LCMC Health Cancer Center, and international collaborators. Funding was provided by the National Institutes of Health. LSU Health New Orleans, the state’s leading health sciences university, operates multiple campuses and educates future health professionals across medicine, dentistry, nursing, public health, allied health, and graduate studies. Its research enterprise is recognized for lifesaving discoveries and significant regional economic impact. ...read more read less