Decrease of Sex Hormone -Binding Globulin, Increase of Sleep Apnea/Hypopnea Event, and Worsened Heart Rate Variability Contribute to the Cardiovascular Risk in Non-Obese Women with Polycystic Ovary Syndrome

• Main Authors: Hsiao-Ping Yang, 楊曉萍
• Other Authors: Shih-Yi Huang
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/28789780695685142506

博士 === 臺北醫學大學 === 保健營養學研究所 === 98 === The prevalence of obstructive sleep apnea (OSA) in obese or overweight women with polycystic ovary syndrome (PCOS) is higher than that in control groups in Western countries. Both OSA and PCOS share insulin resistance (IR) as central pathogenesis. Preliminary data also revealed heart rate variability (HRV) changes that indicate an increase risk for CVD in PCOS. However, obesity is a confounding factor in studying OSA and HRV in PCOS. Our main purpose is that, by excluding the influence of obesity, patients with PCOS still present certain levels of biochemical changes and respiratory abnormalities during sleep. At the same time, they might have autonomous abnormalities during sleep that could be related to their change of respiratory abnormalities. The first study was designed to evaluate the association of body composition, serum biochemical and hormonal factors of non-obese patients with PCOS. When the PCOS group was compared with the control, the levels of high-density lipoprotein cholesterol (HDL-C) and sex hormone-binding globulin (SHBG) levels were significantly lower while high-sensitivity C-reactive protein (hs-CRP) was significantly higher. The fasting insulin, homeostasis model assessment (HOMA) of insulin resistance and results from 2-h glucose challenge test significantly but negatively correlated with SHBG levels. Lower SHBG may be a useful clinical marker to help detect IR in patients of non-obese Taiwanese women with PCOS. The second study was to assess the influence of PCOS on respiratory events during sleep in women who are not obese. Overnight polysomnography (PSG) was performed. Non-obese women with PCOS had a higher total apnea-hypopnea index (AH) especially during non-rapid eye movement stage (AHINREM) than that of the controls. They had a higher serum hs-CRP that was positively correlated with AHIREM. The third study revealewd that the triangular interpolation of NN interval histogram (TINN) of long-term HRV obtained by the ECG in PSG study in the PCOS group was lower in non-obese women with PCOS than those in the control group. TINN had a negative relation with hs-CRP. Both the second and third study showed a positive relationship between hs-CRP and AHIREM. The PCOS patients suffered from worsened cardiac autonomous function that is related to their respiratory abnormalities during sleep, and the cardiovascular risk factor hs-CRP. These studies revealed that serum level changes of SHBG could serve as early signs of worsening of IR. There was a poor respiratory and cardiovascular stability in patients during sleep. They also provide insight into the linkage that the decrease of SHBG, increase of apnea-hypopnea index during sleep, and worsened HRV all contribute to the CVD risk, indirectly or directly, in non-obese women with PCOS.