Worldwide, at least 20 percent of women of reproductive age have polycystic ovaries (PCO), a condition in which the ovaries enlarge and develop many small cysts. About three-quarters of these women have polycystic ovary syndrome (PCOS), which is marked by one or more symptoms that include abnormal menstruation, excessive body hair, obesity, and infertility.
In the first study of its kind, researchers compared the elasticity of arteries in women with normal ovaries, those with PCO, and those with PCOS. On average, women with PCOS had arteries nearly twice as stiff as the arteries in women with normal ovaries. Artery stiffness in women with PCO lay roughly midway between the other two groups.
Stiff arteries are an indication of atherosclerosis. As fatty plaque forms and builds in artery walls, the vessels lose some of their elasticity.
"The implication is that a common condition thought to be primarily a gynecological problem may predispose women to heart disease," says lead author Paul Hardiman, M.D., a senior lecturer in obstetrics and gynecology at Royal Free and University College Medical School in London.
Hardiman and his colleagues used a sophisticated ultrasound system to examine two arteries in the neck, the common carotid artery and the internal carotid artery, which supply blood to the head. They measured arterial stiffness and compliance (the arteries' ability to dilate when the heart needs to pump more blood through the body). If these arteries are stiff it may indicate more extensive artery disease in the rest of the body.
The 60-patient study involved women from the London area and consisted of three groups of 20 women. One group had a confirmed diagnosis of PCOS. Another group had confirmed PCO but without symptoms of PCOS. Women in the third group were healthy and had normal ovaries.
The stiffness index and compliance were calculated by measuring the diameter of the artery during the cardiac cycle. A high stiffness index and low compliance indicate a reduced arterial wall elasticity and are associated with increased mortality from coronary heart disease. The researchers found that the stiffness indices in the common carotid were 6.7 for healthy women, 10.2 for those with PCO, and 12.3 for those with PCOS. In the internal carotid, the stiffness indices were 8.7 in healthy women, 16.2 in those with PCO, and 14.8 in those with PCOS.
The common carotid arteries in women with PCOS had the lowest compliance index at 10.7. Compliance was 14.1 in women with PCO, and 19.2 in healthy women. Similar results were seen in the internal carotid artery: 10.1 in women with PCOS, 11 for those with PCO and 16.9 in healthy women.
Women with PCOS often have elevated cholesterol levels, high blood pressure, obesity, and insulin resistance, which is an inability of the body to use insulin effectively. Insulin resistance increases a person's risk of developing type 2 (adult onset) diabetes, and diabetes sharply increases a person's risk of heart disease. Previous research has estimated that these risk factors can cause up to a 7.4-fold increased risk of heart attack for women with PCOS compared to those without it.
There was no significant difference in age or in total cholesterol, HDL (good) or LDL (bad) cholesterol among the three groups. However, compared with the normal and PCO women, those with PCOS had significantly higher weight, blood pressure, and insulin levels.
Because women with PCOS have other risk factors for heart disease, the researchers statistically controlled for such things as high blood pressure and obesity. They found that the disorder predicted the increased stiffness and decreased compliance of arteries independent of any other risk factor.
The researchers excluded women who smoked, had reproductive problems or cardiovascular disease, or were taking drugs such as contraceptives or aspirin that can affect artery function.
"Hopefully this study will inform cardiologists about an important risk factor for cardiovascular disease in women," he adds.
Hardiman notes that the evidence only indirectly links polycystic ovaries with an increased heart risk, and that the only large study of mortality in PCOS patients found no increase in deaths from cardiovascular disease. Whether this finding resulted from an unintended bias in selecting patients or from some unidentified protective factor remains unknown.
The small number of women in the recent study means further research is needed to confirm or refute these findings, the researchers note.
Co-authors are Kalpana Lakhani, M.Sc., and Alexander M. Seifalian, Ph.D.
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