September 2005

METABOLIC SYNDROME AND MENOPAUSE

Metabolic Syndrome has commanded a good deal of attention in the medical community the past 15 years. Also called Syndrome X, it is estimated to affect 20-30 percent of the middle-aged population in the United States . Due to increases in obesity and sedentary lifestyles, that number is likely to rise in the next 10 years.

The metabolic syndrome has five major components:

One only need have three of the five to be considered with a diagnosis of metabolic syndrome. This combination of factors significantly increases the risk of heart disease and Type 2 diabetes. Since heart disease is the number one cause of death among American women, affecting one out of two we must consider what is happening hormonally that may predispose us to this pervasive disease.

Menopause is defined as the cessation of menses for 12 consecutive months. For years prior, hormones fluctuate considerably with the greatest change being the diminished production of the hormone progesterone. This decrease occurs even before the menstrual periods become irregular but certainly at the time they stop completely. Most women (unless they undergo surgical menopause or chemotherapy) continue to produce estrogen and heavier women can produce a considerable amount. Because progesterone is produced when ovulation occurs, once ovulation ceases, so does it's production.

Progesterone and estrogen work synergistically in many ways. The cardiovascular system is one example. Progesterone (not synthetic progestin) aids in lowering LDH levels. In addition, progesterone has been proven to decrease myocardial ischemia (decrease in oxygen to the heart) in exercising women taking estrogen. This achieved by stimulating the release of nitrous oxide (which is the treatment of choice in patients with chest pain from myocardial ischemia) from the cells of the blood vessels to the heart. In addition, progesterone inhibits the expression of vascular adhesion cells. Vascular adhesion cells promote the build-up of plaque in blood vessels. This was not the case when progestins were used.

This is significant because there is a 4 fold increase in the rate of cardiovascular disease (CVD) 10 years following natural menopause. 45% of post-menopausal women demonstrated an increase in thickening of the wall of their carotid arteries compared to 16% of age matched premenopausal women. Thickening of the major arteries is one of the factors that predisposes to heart disease.

Additionally, the transition into menopause is associated with a 16% increase in triglyceride levels. Elevated triglyceride levels are an excellent predictor of CVD in women. There is also a decrease in HDL levels post-menopausally, another component of metabolic syndrome. HDL is protective against CVD. Though not a component, LDL level are higher during this time of life.

Body fat distribution is altered with menopause. There is an increase in abdominal fat with a simultaneous decrease in lean body mass. These changes are independent of age and body weight.

It has long been recognized that the central distribution of fat or "apple shape" is associated with an increased risk of heart disease. Women with high amounts of abdominal fat are also found to have an increase in LDL and a decrease in HDL. The decrease may reflect an increase in sedentary lifestyle during which time the metabolic rate decreases and less fat is burned.

As abdominal obesity is also associated with increased insulin resistance resulting in increased levels of blood glucose and hyperinsulinemia, the risk of Type 2 diabetes is increased. As you will remember, this is another component of the metabolic syndrome.

All of these factors lead us to conclude that women who may already be at risk either because of their family medical history, obesity, hypertension or a sedentary lifestyle will be at increased risk for developing metabolic syndrome once they become menopausal.

An aggressive approach for treatment should include lifestyle changes, diet, exercise and the appropriate medications to manage elevated cholesterol and hypertension. In addition, as a gynecologist, I am always interested in hormone status and what I may do to improve imbalance using nonsynthetic (bio-identical) hormone treatment. There is no reason why, working together, the patient and her physician cannot realize optimal results for a healthier life!

Dr. Sheila Allison is a local gynecologist who practices at Southpoint Medicine and Women 's Associates, 6216 Fayetteville Road , Durham. 405-7000