Sleep Apnea Related to Insulin Resistance in Women With PCOS


SAN FRANCISCO — A high risk for sleep apnea was common in women with polycystic ovary syndrome and was linked to high fasting insulin levels, Dr. Esra Tasali reported at a conference sponsored by the American Diabetes Association.

Among the women with normal glucose tolerance, insulin levels in response to oral glucose were twice as high in the women at high risk for sleep apnea, compared with those who were at low risk.

This finding suggests that sleep apnea might worsen the metabolic consequences of insulin resistance, accelerating the conversion from normal to impaired glucose tolerance, Dr. Tasali said.

Although the study does not establish causation, Dr. Tasali recommended that women with polycystic ovary syndrome (PCOS) be systematically evaluated for sleep apnea because treatment of existing sleep apnea might improve glucose metabolism.

A high risk for sleep apnea was observed in 30 of 40 women with PCOS, and 92% of the women had sleep problems, according to Dr. Tasali and her colleagues at the University of Chicago (J. Clin. Endocrinol. Metab. 2006;91:36–42).

Of the 40 women, 32 had previously been given an oral glucose tolerance test. Glucose tolerance was normal in 19 women.

In 22 women at high risk of sleep apnea, average fasting insulin levels were significantly higher (168 pmol/L) than they were in the 10 women at low risk of apnea (97 pmol/L), Dr. Tasali said.

Among the 13 women who had impaired glucose tolerance, glucose and insulin levels did not differ depending on the their level of risk for sleep apnea.

Another cohort of eight women with PCOS underwent overnight polysomnography for symptoms suggestive of obstructive sleep apnea.

Mean sleep efficiency was 80% in the women with PCOS, compared with 92% in a control group of age-matched, nonobese women.

The women with PCOS also had significantly longer mean sleep latency (41 minutes compared with 10 minutes), and significantly shorter total sleep time (323 minutes compared with 442 minutes, a difference of almost 2 hours).

“Sleep apnea might be an intrinsic component of the metabolic disturbances that appear with polycystic ovary syndrome,” Dr. Tasali said.

Furthermore, severity of sleep apnea as measured by the apnea-hypopnea index, and the degree of oxygen desaturations during rapid-eye-movement sleep, accounted for more than 90% of the variability in measures of glucose tolerance including hemoglobin A1c levels.

Together, these findings could mean that both glucose tolerance and sleep apnea are strongly influenced by a common mechanism in women with PCOS.

Dr. Tasali disclosed that she had no conflict of interest related to her presentation.

Next Article: