Sleep Apnea and Neuroendocrine Function

Obesity may be the common pathway for sleep-disordered breathing in women with polycystic ovary syndrome

OBJECTIVE

Polycystic ovary syndrome (PCOS) is one of the most common endocrinological disorders in women of reproductive age, and is characterized by hyperandrogenism. It is associated with long-term metabolic dysfunctions including sleep-disordered breathing (SDB). We hypothesized that the increased prevalence of SDB in PCOS results from raised testosterone levels.

METHODS

This was a prospective, cross-sectional, case-control study in which 50 case patients with untreated PCOS and 100 control subjects were included. All the case patients and control subjects went through a detailed clinical, biochemical, and hormonal evaluation. Overnight polysomnography was performed in all case patients and the snorers (16 of 100) in the control group.

RESULTS

SDB was seen in 66% of the case patients and in 4% of control group with (odds ratio [OR] = 46.5, 95% confidence interval [CI] = 14.6-148.4; p <0.001). After adjustment for body mass index (BMI) and waist circumference (WC), the difference was not significant (p = 0.993 and p = 0.931, respectively). The SDB patients with PCOS showed significantly higher respiratory distress index (RDI) values than SDB patients in the control group (22.5 ± 21.5 vs 9.0 ± 5.6, p = 0.01). On the Epworth Sleepiness Scale the PCOS case patients reported feeling more sleepy than did the control subjects (12.5 ± 3.2 vs 9.32 ± 1.7, p <0.001). Free testosterone levels were also significantly higher in the PCOS group than in the control subjects (2.95 ± 3.44 vs 1.5 ± 1.0, p <0.001). There was a significant correlation between free testosterone level and RDI values (r = 0.377; p = 0.007), WC (r = 0.315; p = 0.026), and BMI (r = 0.398; p = 0.004). A significant correlation of WC (r = 0.551; p <0.001) and BMI (r = 0.572; p <0.001) was observed with RDI.

CONCLUSION

Testosterone-induced obesity is probably the common pathway for the development of SDB in PCOS.

Impact of sleep-disordered breathing on metabolic dysfunctions in patients with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrinological disorder among women in the reproductive age group. These women are prone to develop sleep-disordered breathing (SDB) and metabolic disorders. SDB is also associated with metabolic dysfunctions. We hypothesized that SDB is an independent risk factor contributing to metabolic dysfunctions in women with PCOS.

METHODS

Prospective cross-sectional study in which 50 women with PCOS and not on any treatment were selected. They were divided into two groups: Group 1 - PCOS with SDB and Group 2 - PCOS without SDB.

RESULTS

Thirty-three (66%) women with PCOS had SDB. Women in Group 1 had significantly higher systolic blood pressure (SBP) (P = 0.002); diastolic blood pressure (DBP) (P = 0.044); fasting blood sugar (P = 0.006), triglyceride levels (P = 0.014) and mean Ferriman-Gallwey score (P = 0.028). The HDL was significantly lower in group 1 (P = 0.006). In group 1, 42.4% of women had metabolic syndrome (P < 0.001). Excessive daytime sleepiness (EDS) was significantly higher in Group 1 (P = 0.04). Respiratory distress index significantly correlated positively with waist circumference (r = 0.551, P < 0.001), SBP (r = 0.455, P = 0.001), DBP (r = 0.387, P = 0.006), FBS (r = 0.524, P = 0.000), homeostatic model assessment (r = 0.512, P = 0.000), triglycerides (r = 0.384, P = 0.006), free testosterone (r = 0.390, P = 0.005), and negatively with HDL (r = -0.555, P < 0.001).

CONCLUSION

Women with PCOS and SDB had significantly increased metabolic abnormalities as well as more severe hyperandrogenism. Women with PCOS who have metabolic abnormalities or severe hyperandrogenism should undergo an overnight PSG.

Continuous positive airway pressure increases pulsatile growth hormone secretion and circulating insulin-like growth factor-1 in a time-dependent manner in men with obstructive sleep apnea: a randomized sham-controlled study

STUDY OBJECTIVES

To assess the time-dependent effect of continuous positive airway pressure (CPAP), on insulin-like growth factor-1 (IGF-1), IGF binding proteins (IGFBPs) and pulsatile growth hormone (GH) secretion.

DESIGN

A randomized, double-blind, sham-controlled, parallel group study.

PARTICIPANTS

Sixty-five middle-aged men with moderate to severe obstructive sleep apnea.

INTERVENTION

Active (n = 34) or sham (n = 31) CPAP for 12 weeks, followed by 12 weeks of active CPAP (n = 65).

MEASUREMENTS AND RESULTS

Fasting morning IGF-1, IGFBP-3, and IGFBP-1 blood levels at 0, 6, 12, and 24 weeks. Overnight GH secretion was calculated by mathematical deconvolution of serial GH measurements from serum samples collected every 10 min (22:00-06:00) during simultaneous polysomnography in a subset of 18 men (active n = 11, sham n = 7) at week 12. Active, compared with sham, CPAP increased IGF-1 at 12 weeks (P = 0.006), but not at 6 weeks (P = 0.44). Changes in IGFBP-3 and IGFBP-1 were not different between groups at 6 or 12 weeks (all P ≥ 0.15). At week 24, there was a further increase in IGF-1 and a decrease in IGFBP-1 in the pooled group (P = 0.0001 and 0.046, respectively). In the subset, total (P = 0.001) and pulsatile (P = 0.002) GH secretion, mean GH concentration (P = 0.002), mass of GH secreted per pulse (P = 0.01) and pulse frequency (P = 0.04) were all higher after 12 weeks of CPAP compared with sham. Basal secretion, interpulse regularity, and GH regularity were not different between groups (all P > 0.11).

CONCLUSIONS

Twelve weeks, but not 6 weeks, of CPAP increases IGF-1, with a further increase after 24 weeks. Total and pulsatile GH secretion, secretory burst mass and pulse frequency are also increased by 12 weeks. CPAP improves specific elements of the GH/IGF-1 axis in a time-dependent manner.

CLINICAL TRIALS REGISTRATION

Australia New Zealand Clinical Trials Network, www.anzctr.org.au, number ACTRN12608000301369.

Diagnosis and treatment of sleep apnoea in women with schizophrenia

BACKGROUND

Obstructive sleep apnoea (OSA) is often overlooked in the context of schizophrenia because its hallmark, daytime sleepiness, is so easily attributable to antipsychotic drugs. This is a special problem for women.

AIMS

To underscore the importance of diagnosing and treating OSA in women with schizophrenia.

METHODS

A review of the recent literature (search terms: Obstructive Sleep Apnoea; Schizophrenia; Women (or Gender); Obesity; Antipsychotics; Continuous Positive Airway Pressure (CPAP)) as it applies to a composite case vignette taken from the files of a specialty clinic that treats women with psychosis.

RESULTS

The rate of OSA in women who are both obese and postmenopausal is very similar to that of men. Family history, smoking, and the use of tobacco, alcohol and of antipsychotic medication increase the risk. Despite reluctance, patients with schizophrenia generally agree to undergo sleep studies. Compliance with CPAP is difficult, but can be aided by the physician and is, on the whole, relatively high in women. CPAP improves sleep parameters and may also improve cardiometabolic and cognitive indices, although this still needs to be more fully researched.

CONCLUSION

Schizophrenia and untreated OSA are both associated with high mortality rates in women as well as men.

Cardiometabolic aspects of the polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder amongst women of reproductive age and is associated with various metabolic perturbations, in addition to chronic anovulation and factors related to androgen excess. In general, women live longer than men and develop cardiovascular disease at an older age. However, women with PCOS, as compared with age- and body mass index-matched women without the syndrome, appear to have a higher risk of insulin resistance, hyperinsulinemia, glucose intolerance, dyslipidemia, and an increased prothrombotic state, possibly resulting in a higher rate of type 2 diabetes mellitus, fatty liver disease, subclinical atherosclerosis, vascular dysfunction, and finally cardiovascular disease and mortality. Further alterations in PCOS include an increased prevalence of sleep apnea, as well as various changes in the secretion and/or function of adipokines, adipose tissue-derived proinflammatory factors and gut hormones, all of them with direct or indirect influences on the complex signaling network that regulates metabolism, insulin sensitivity, and energy homeostasis. Reviews on the cardiometabolic aspects of PCOS are rare, and our knowledge from recent studies is expanding rapidly. Therefore, it is the aim of the present review to discuss and to summarize the current knowledge, focusing on the alterations of cardiometabolic factors in women with PCOS. Further insight into this network of factors may facilitate finding therapeutic targets that should ameliorate not only ovarian dysfunction but also the various cardiometabolic alterations related to the syndrome.

Impact of obstructive sleep apnea on insulin resistance and glucose tolerance in women with polycystic ovary syndrome

CONTEXT

Insulin resistance, impaired glucose tolerance, and type 2 diabetes are common in women with polycystic ovary syndrome (PCOS). Obstructive sleep apnea (OSA) has been linked to metabolic dysfunction. We studied women with and without PCOS to determine the extent to which OSA is responsible for insulin resistance and glucose intolerance in PCOS.

METHODS

In a prospective design, 52 women with PCOS and 21 women without PCOS of similar age and body mass index had an overnight polysomnogram and a 75-g oral glucose tolerance test.

RESULTS

Twenty-nine women (56%) with PCOS had OSA compared with four controls (19%) (adjusted odds ratio 7.1; 95% confidence interval, 1.7-45.7; P = 0.01). PCOS women with OSA were more insulin resistant than those without OSA [homeostasis model assessment (HOMA) index 5.7 +/- 0.4 vs. 3.5 +/- 0.4; P = 0.006] after controlling for age, body mass index, and ethnicity. Impaired glucose tolerance was found in 16 of 29 (55%) PCOS women with OSA and only six of 23 (26%) of those without OSA (unadjusted P = 0.049). Insulin resistance and glucose intolerance were highly correlated with the presence and severity of OSA. Among PCOS women with normal glucose tolerance, the presence of OSA was associated with a nearly 2-fold higher fasting insulin level and HOMA index. The severity of OSA was a highly significant predictor of the fasting concentrations of glucose and insulin as well as the 2-h glucose concentration and HOMA index.

CONCLUSIONS

OSA is a highly prevalent and important determinant of insulin resistance, glucose intolerance, and type 2 diabetes in PCOS.

Polycystic Ovary Syndrome and Obstructive Sleep Apnea

Polycystic ovary syndrome (PCOS), the most common endocrine disorder of pre-menopausal women, is characterized by chronic hyperandrogenism, oligoanovulation, obesity and insulin resistance. Importantly, PCOS women are at increased risk for glucose intolerance, type 2 diabetes and cardiovascular disorders. Recent reports indicate an unexpectedly high prevalence of obstructive sleep apnea (OSA) in PCOS. Alterations in sex steroids (i.e. high androgen and low estrogen levels) and increased visceral adiposity in PCOS could potentially contribute to the increased prevalence of OSA in this disorder. There is some evidence to suggest that there may be strong associations between the presence and severity of OSA and the metabolic disturbances that characterize PCOS. Causal mechanisms in the link between PCOS and OSA remain to be elucidated. Clinicians who manage PCOS patients should be aware of the high prevalence of OSA in these patients and systematically evaluate these women for sleep disturbances.