Diabetes Forecast

PCOS and Its Links to Diabetes in Women

By Erika Gebel, PhD ,

Excessive facial hair and acne aren't things that many women want to deal with, but these cosmetic issues may be a signal of an underlying problem: polycystic ovary syndrome (PCOS). This condition affects between 5 and 10 percent of women of reproductive age in the United States and is the No. 1 cause of infertility. Several studies have found links between PCOS and diabetes, a connection that may help researchers understand the causes of PCOS and improve its treatment.

Signs of PCOS

Excess facial or body hair (male-pattern hair growth)

Male-pattern baldness

Acne, oily skin, or dandruff

Infrequent or irregular periods

Dark or thick patches of skin on the neck, arms, breasts, or thighs

The Diagnosis

A syndrome, such as PCOS, is defined as a collection of signs that occur together, as opposed to a disease with just a single cause. PCOS signs include excess hair growth (on the face, sternum, middle abdomen, upper back, or inner thigh), acne, irregular periods, cysts on the ovaries, and high levels of androgen hormones (such as testosterone). But not everyone with PCOS will have all these traits, says Thomas Barber, PhD, an associate professor of endocrinology and diabetes at the University of Warwick in the United Kingdom. PCOS is "a heterogeneous condition," says Barber, which means that it can present itself in a variety of ways in different people.

To diagnose PCOS, doctors have to rule out other conditions such as thyroid disease, early menopause, or adrenal gland disorders that could trigger the same set of signs. "It's a diagnosis of exclusion," says Corrine Welt, MD, a reproductive endocrinologist at Massachusetts General Hospital and an associate professor of medicine at Harvard Medical School. Doctors sometimes use ultrasound to check the ovaries for cysts, but many women who have these cysts don't have PCOS, and women with PCOS may not show polycystic ovaries. "The cysts are just normal follicles, eggs surrounded by fluid," says Welt. "They're not big or painful." Normally, these eggs mature and then leave the ovary for a chance at fertilization, but in women with PCOS the mature eggs get stuck in the ovary. This can make it difficult to become pregnant.

Besides infertility, PCOS is associated with additional conditions, including type 2 diabetes. "There is an increased risk of endometrial cancer, depression, anxiety, heart disease, hypertension, and lipid abnormalities," says Welt. "They have to be very careful about cardiovascular risk."

Doctors often prescribe birth control pills to normalize menstruation in PCOS. "Birth control is probably the best treatment," says Welt. "It regulates cycles and suppresses androgen hormones." Medications such as spironolactone reduce hair growth and improve acne. For women wanting to get pregnant, Welt says clomiphene, a drug that induces ovulation, often has good results. Though metformin isn't intended to treat PCOS, some doctors are using the blood glucose–lowering medication in women with PCOS and seeing improvements.

Causes, Mysteries, and Diabetes

No one knows what causes PCOS, but scientists think that the condition is, in part, genetic. "It's very clear from [studies in twins] that there is a genetic predisposition for PCOS," says Barber. But not everyone with PCOS genes develops the condition, so researchers are looking for lifestyle factors that affect the risk for PCOS.

Most experts agree that PCOS is related to body weight. "You're born with a genetic predisposition for the condition, but then you increase risk by carrying excess weight," says Barber. Weight loss, even just 5 percent of body weight, can improve PCOS symptoms. "If you have PCOS, you really want to exercise and keep your weight down," says Welt, who also supports checking for diabetes in women with PCOS regardless of weight. Extra body fat may be part of the connection between PCOS and type 2 diabetes, which is also associated with obesity. About half the women with PCOS are lean, but most have underlying insulin resistance.

Insulin and PCOS

Women with type 1 diabetes are also at increased risk for PCOS, suggesting that insulin may be a key factor. People with type 1 get their insulin from outside the body, an unnatural situation where the ovaries see more insulin than they would otherwise, says Barber. The same is true in people with type 2 diabetes, who tend to have high levels of insulin in the early years of the disease because their bodies churn it out to combat their insulin resistance. "It's the raised insulin that has a direct effect on the ovaries," says Barber. "It enhances the production of testosterone in the ovary." That increased testosterone may be behind the syndrome, suppressing the release of eggs from the ovary and promoting the signs of PCOS. But this is just one theory, says Barber. More study is needed, he adds, before researchers figure out the root cause of PCOS.



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