Differential Effects of Obesity on Obstructive Sleep Apnea Syndrome according to Age

OBJECTIVE: To evaluate the effect of obesity on obstructive sleep apnea syndrome (OSAS) by age in relation to anthropometric measurements. METHODS: The medical records of 1,110 participants diagnosed with OSAS were analyzed according to age. All participants underwent nocturnal polysomnography and had their body mass index, waist circumference, neck circumference (NC), and waist-to-hip ratio measured. RESULTS: According to the multiple linear regression analysis model for the natural logarithm of the apnea-hypopnea index treating all four anthropometric measurements and gender as covariates, the final stepwise model accounted for an increasing percentage of the variability in the severity of OSAS as a function of age: 7.0, 9.1, 14.5, and 25.6% for those aged <30, 30–39, 40–49, and 50–59 yrs, respectively. It accounted for a decreased percentage among those 60–69 (20.3%) and 70 yrs or older (3.9%). The correlation between NC and the severity of OSAS linearly increased as a function of age for those aged 30–59 yrs, peaked among those in their 60s, and dramatically decreased thereafter. CONCLUSION: Middle-aged patients with OSAS were more likely to be obese, as measured by anthropometric measurements, than were younger or older OSAS patients. In particular, the predictive value of NC was significantly lower for younger and older OSAS patients.

Transdermal Nicotine Patch Effects on EEG Power Spectra and Heart Rate Variability During Sleep of Healthy Male Adults

OBJECTIVE: The effect of transdermal nicotine patch on sleep physiology is not well established. The current study aimed to examine the influence of nicotine patch on homeostatic sleep propensity and autonomic nervous system. METHODS: We studied 16 non-smoking young healthy volunteers with nocturnal polysomnography in a double blind crossover design between sleep with and without nicotine patch. We compared the sleep variables, sleep EEG power spectra, and heart rate variability. RESULTS: The night with nicotine patch showed significant increase in sleep latency, wake after sleep onset, and stage 1 sleep; and decrease in total sleep time, sleep efficiency, and percentage of REM sleep. Also, spectral analysis of the sleep EEG in the night with nicotine patch revealed decreased slow wave activity in stage 2 and REM sleep and increased alpha activity in the first NREM-REM sleep cycle. Heart rate variability showed no differences between the 2 nights, but the low to high ratio (a parameter indicative of sympathetic nervous system activity) positively correlated with wake after sleep onset in night with nicotine patch. CONCLUSION: Transdermal nicotine patch significantly disrupts sleep continuity, sleep architecture, and homeostatic sleep propensity. The overactivation of the sympathetic nervous system may be responsible for these changes.

The Sleep Characteristics of Chronic Schizophrenia Patients with Insomnia in Community-based Mental Health Services / 수면정신생리

OBJECTIVES: To evaluate sleep characteristics and factors associated with sleep disturbance in schizophrenia patients with concurrent active psychotic symptoms and insomnia. METHODS: Schizophrenia patients with insomnia and active psychotic symptoms (n = 63) were recruited from communitybased mental rehabilitative facilities. Sleep scales such as the Korean version of the Insomnia Severity Index (ISI-K) and the Korean Version of the Pittsburgh Sleep Quality Index (PSQI-K) were evaluated and those with ISI-K >15 were included in the study. Psychotic, anxiety and depressive symptoms were rated with the Brief Psychotic Rating Scale (BPRS), the Korean Version of the Anxiety Sensitivity Index (K-ASI), and the Korean Version of the Beck Depression Inventory-I (K-BDI), respectively. Pearson correlation analyses were performed between the sociodemographic data, ISI-K and PSQI-K. Multiple linear regression analysis was conducted to investigate the factors which affected the ISI-K and PSQI-K. RESULTS: The mean ISI-K and PSQI-K scores were 18.1 ± 2.6 and 12.0 ± 2.2, respectively. Pearson correlation analysis showed a negative correlation between age of onset and ISI-K score and positive correlations between BRPS and PSQI-K scores and between K-ASI and both ISI-K and PSQI-K scores. Multiple regression analyses for both ISI-K and PSQI-K with K-ASI, age of onset, and BPRS as covariates revealed K-ASI as the only significant remaining factor. CONCLUSION: Our study suggests that anxiety symptoms are associated with insomnia symptoms in schizophrenia patients regardless of depressive or psychotic symptoms.

Insomnia in North Korean Refugees: Association with Depression and Post-Traumatic Stress Symptoms

OBJECTIVE: We investigated the prevalence of insomnia and its clinical characteristics in North Korean refugees. METHODS: North Korean refugees living in South Korea (48 males, 129 females; mean age 38.22+/-12.24 years) and South Koreans (112 males, 203 females; mean age 39.48+/-10.32 years) completed the following questionnaires: the Self-reported Questionnaire on Insomnia, Center for Epidemiological Studies-Depression Scale (CES-D), Trauma Exposure Check List for North Korean Refugees, and the Impact of Event Scale-Revised (IES-R). RESULTS: North Korean refugees had insomnia more often than South Koreans did (38.42% vs. 8.89%). Depression combined with insomnia was also more prevalent in North Korean refugees (28.25% vs. 3.17%). Compared with South Koreans with insomnia, North Korean refugees with insomnia showed higher CES-D scores. The North Korean refugees with insomnia had experienced a larger number of traumatic events, and had higher CES-D and IES-R scores compared to North Korean refugees without insomnia. Insomnia in North Korean refugees was also associated with the presence of significant depressive and post-traumatic stress disorder (PTSD) symptoms. CONCLUSION: Insomnia was common in North Korean refugees and was closely associated with depressive and PTSD symptoms. Our study suggests that complaints of insomnia may indicate more severe psychopathology, especially in refugees.

Sleep EEG Characteristics in Young and Elderly Patients with Obstructive Sleep Apnea Syndrome

OBJECTIVE: In the present study, it was hypothesized that the sleep electroencephalogram (EEG) characteristics of young (55 yrs) OSAS patients would differ. METHODS: We analyzed 76 sleep EEG recordings from OSAS patients (young group: n=40, mean age: 24.3±4.9 yrs; elderly group: n=36, mean age: 59.1±4.9 yrs), which were obtained during nocturnal polysomnography. The recordings were assessed via spectral analysis in the delta (0.5–4.5 Hz), theta (4.5–8 Hz), alpha (8–12 Hz), beta (12–32 Hz), slow sigma (11–13 Hz), and fast sigma (13–17 Hz) frequency bands. RESULTS: Apnea Hypopnea Index (AHI) and sleep efficiency (%) did not differ significantly between the two groups (19.8±14.4 vs. 25.9±16.0, p=0.085; 84.4±12.6 vs. 80.9±11.0, p=0.198, respectively). After adjusting for gender, the slow/fast sigma ratio was not significantly correlated with AHI in the elderly group (r=-0.047, p=0.790) but AHI was inversely correlated with the slow/fast sigma ratio in the young group (r=-0.423, p=0.007). A multiple linear regression analysis revealed that a higher AHI was related with a lower slow/fast sigma ratio in the young group (β=-0.392, p=0.028) but not the elderly. CONCLUSION: In the present study, sleep EEG activity differed between young and elderly OSAS patients. The slow/fast sigma ratio was associated with OSAS severity only in young patients, suggesting that young OSAS patients may have a distinctive brain plasticity compared with elderly patients.