Young obese women who are otherwise healthy have hearts that exhibit changes in structure and function similar to those of hypertensive patients, which may help explain links between obesity and heart failure risk, according to a new study in the April 21, 2004 issue of the Journal of the American College of Cardiology.
“The higher the body mass index was, i.e., the more overweight or obese a woman was, the thicker the heart wall was, the more concentric remodeling there was, the worse the diastolic and systolic function,” said Linda R. Peterson, MD, FACC from Washington University School of Medicine in St. Louis.
Dr. Peterson noted that the primary importance of this small observational study is that it may help clarify proposed mechanisms for explaining links between obesity and heart disease. And while the changes they observed may be warning signs of future health problems, the obese women in this study did not have heart disease.
“These changes do not equate to clinical heart failure. This study does, however, provide a basis for future research studies that are designed to further investigate the mechanisms by which obesity causes these differences and to investigate the implications of these differences,” Dr. Peterson added.
The researchers studied 51 premenopausal, healthy young women who did not have diabetes, high blood pressure or any other active disease process; 20 were obese (body mass index [BMI] =30 kg/m2) and 31 were non-obese (BMI <30 kg/m2). The researchers used ultrasound to evaluate the shape and function of the hearts of participants. Unlike some earlier studies, the researchers took measurements that allowed them to specifically account for the effects of increased blood volume, which is typically seen in obese patients.
Obesity was associated with thickening of the heart wall compared to the size of the left ventricle, a feature known as concentric remodeling. In addition, the obese women had decreased systolic (ventricle contraction) and diastolic (ventricle filling) heart function. Analyses that accounted for the effects of other factors indicated that body mass index was the only independent predictor of the changes that the researchers observed.
“Further studies are needed to determine the full impact of these findings, but we have shown that these changes can be quantified and that obesity definitely has a particular effect on the heart, even in young people, and so now we are better able to study it, its effects and its causes,” Dr. Peterson said.
Carl J. Lavie, MD, FACC from the Ochsner Clinic Foundation in New Orleans, who was not connected to this study, said, “This manuscript is important since it demonstrates that even young patients with obesity, who have not yet developed hypertension, already have alterations in ventricular function, further supporting the deleterious effects of obesity on the cardiovascular system.”
Pier L. Temporelli, from the Salvatore Maugeri Foundation in Veruno, Italy, who also was not part of this research team, called the article “a fascinating paper which helps explain why there is an increased risk of heart failure in young healthy obese women.”
“By adopting relatively new echocardiographic techniques, the authors have for the first time demonstrated that obese young women have concentric left ventricular remodeling and early abnormalities of both diastolic and systolic function,” Dr. Temporelli said.
Dr. Temporelli called for large studies to further explore the issue and to see if similar results are seen in men and African-American women.
The American College of Cardiology, a 29,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.