Chevy Chase, MD-- Postmenopausal women who have higher testosterone levels may be at greater risk of heart disease, insulin resistance and the metabolic syndrome compared to women with lower testosterone levels, according to a new study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM). This new information is an important step, say researchers, in understanding the role that hormones play in women's health.
"For many years, androgens like testosterone were thought to play a significant role in men only and to be largely irrelevant in women," said Anne Cappola, MD, of the University of Pennsylvania School of Medicine in Philadelphia. "It is now largely accepted that premenopausal women with polycystic ovary syndrome, a condition in which androgens are elevated, have increased health risks. However, the clinical relevance of testosterone in women over the age of 65 had remained uncertain until this recent study."
In this study, researchers measured levels of testosterone in 344 women, aged 65-98 years. They found that women with the highest testosterone levels -- in the top 25 percent of this study group-- were three times as likely to have coronary heart disease compared to women with lower testosterone levels. These women were also three times as likely to have a group of metabolic risk factors called the metabolic syndrome compared to women with lower testosterone levels.
The connection between higher levels of testosterone and these health risks may be explained by the researcher's finding of a greater degree of insulin resistance in women with the highest testosterone levels. Insulin resistance is a metabolic disturbance in which the body does not use insulin efficiently and is itself a risk factor for the metabolic syndrome and cardiovascular disease.
"Because of the observational aspect of this study, we cannot discern if testosterone is a marker or mediator of cardiovascular disease in this population," said Cappola. "Further studies are needed to determine if a causal relationship exists between testosterone and insulin resistance and to provide more insight into the role testosterone plays in the pathogenesis of cardiovascular disease in women."
Other researchers working on the study include Shrita Patel, Sarah Ratcliffe, Muredach Reilly and Rachel Weinstein of the University of Pennsylvania in Philadelphia; Shalender Bhasin of Boston University in Massachusetts; Marc Blackman of the Veterans Affairs Medical Center in Washington, D.C.; Jane Cauley and Kim Sutton-Tyrrell of the University of Pittsburgh in Pennsylvania; and Linda Fried of Columbia University in New York, N.Y.
The article, "Higher Testosterone Levels Are Associated with Insulin Resistance, Metabolic Syndrome, and Cardiovascular Disease in Older Women," will appear in the December 2009 issue of JCEM.
Founded in 1916, The Endocrine Society is the world's oldest, largest and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Society's membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 100 countries. Society members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society and the field of endocrinology, visit our site at www.endo-society.org.