Summary
Periodic limb movements during sleep and obstructive sleep apnea are both associated with increased sympathetic tone, and have been proposed as risk factors for heart diseases and, in ...particular, cardiovascular disease. As sympathetic system activation may lead to dyslipidaemia, periodic limb movements during sleep could be an additional risk factor for cardiovascular disease in patients with obstructive sleep apnea. The aim of the study was to determine whether the presence of periodic limb movements during sleep affects serum lipid levels in obstructive sleep apnea. Total cholesterol, low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol, non‐ high‐density lipoprotein cholesterol and triglyceride levels were investigated in 4138 patients with obstructive sleep apnea in the European Sleep Apnea Database (ESADA) cohort, divided into those with periodic limb movements during sleep index ≥ 15 per hr (n = 628) and controls (n = 3510). ANCOVA adjusted for age, sex, body mass index, apnea–hypopnea index, alcohol intake, smoking status, diabetes, insomnia and study site was used to assess differences in lipids between periodic limb movements during sleep and controls. Patients with periodic limb movements during sleep (24% female, 54.4 ± 12.1 years, body mass index 31.9 ± 5.8 kg m−2, apnea–hypopnea index 36.7 ± 25.4 per hr) had higher triglyceride (1.81 ± 1.04 versus 1.69 ± 0.90 mmol L−1, p = 0.002) and lower high‐density lipoprotein cholesterol (1.19 ± 0.34 versus 1.24 ± 0.37 mmol L−1, p = 0.002) levels, whilst there was no difference in either total cholesterol (4.98 ± 1.10 versus 4.94 ± 1.07 mmol L−1), low‐density lipoprotein cholesterol (3.04 ± 0.96 versus 2.98 ± 0.98 mmol L−1) or non‐ high‐density lipoprotein cholesterol (3.78 ± 1.10 versus 3.70 ± 1.05 mmol L−1) concentrations (all p > 0.05). The results remained unchanged after most sensitivity analyses. Patients with obstructive sleep apnea with periodic limb movements during sleep had more prevalent cardiovascular disease (11% versus 6%, p < 0.01). Periodic limb movements during sleep in obstructive sleep apnea is associated with dyslipidaemia independently of important confounders. Our results highlight periodic limb movements during sleep as an additional risk factor for cardiovascular disease in obstructive sleep apnea.
Obstructive sleep apnea (OSA) has been associated with dysregulation of the hypothalamic–pituitary–adrenal axis and alterations in glucose metabolism with increased risk for type 2 diabetes. The aim ...of the current study was to compare morning plasma cortisol levels and glucose metabolism parameters between moderate (apnea–hypopnea index (AHI): 15–30 events/h) and severe OSA patients (AHI >30 events/h), with respective controls. A total of 56 male OSA patients, 24 moderate (AHI = 21.1 ± 5.3) and 32 severe (AHI = 49.7 ± 18.1), underwent a full-night polysomnography, oral glucose tolerance test (OGTT), and measurement of morning plasma cortisol levels. These groups were compared to 20 matched subjects in a control group. Morning plasma cortisol levels were statistically lower in severe OSA group than in moderate OSA and control groups (303.7 ± 93.5 vs. 423.9 ± 145.1 vs. 417.5 ± 99.8 pmol/L,
P
< 0.001). Significant negative correlations were found between morning plasma cortisol levels and AHI (
r
= −0.444,
P
= 0.002), as well as oxygen desaturation index (
r
= −0.381,
P
= 0.011). Fasting plasma glucose (5.0 ± 0.5 vs. 5.4 ± 0.7 vs. 4.9 ± 0.6 mmol/L,
P
= 0.009) was higher in the severe OSA group compared to moderate OSA and controls. Homeostasis model assessment insulin resistance (HOMA-IR) was higher in the severe OSA group compared to moderate OSA and controls (4.6 ± 3.7 vs. 2.7 ± 2.0 and 2.2 ± 1.8, respectively,
P
= 0.006). In conclusion, our study showed that morning plasma cortisol levels measured at 8 a.m. were significantly lower in severe OSA patients than those in moderate OSA group and controls. Morning plasma cortisol levels showed a negative correlation with AHI and oxygen desaturation index. Additionally, this study confirmed the evidence of glucose metabolism impairment in moderate and severe OSA patients, with more pronounced effect in the severe OSA patients group.
It has been shown that the measures of social distancing and lockdown might have had negative effects on the physical and mental health of the population. We aim to investigate the sleep and ...lifestyle habits as well as the mood of Croatian medical (MS) and non-medical students (NMS) during the COVID-19 lockdown. The cross-sectional study included 1163 students (21.6% male), whose lifestyle and sleep habits and mood before and during the lockdown were assessed with an online questionnaire. The shift towards later bedtimes was more pronounced among NMS (~65 min) compared to MS (~38 min), while the shift toward later wake-up times was similar in both MS (~111 min) and NMS (~112 min). All students reported more frequent difficulty in falling asleep, night-time awakenings and insomnia (
< 0.001) during lockdown. A higher proportion of MS reported being less tired and less anxious during lockdown compared to pre-lockdown (
< 0.001). Both student groups experienced unpleasant moods and were less content during lockdown compared to the pre-lockdown period (
< 0.001). Our results emphasize the need for the promotion of healthy habits in the youth population. However, the co-appearance of prolonged and delayed sleep times along with decreased tiredness and anxiety among MS during lockdown reveals their significant workload during pre-lockdown and that even subtle changes in their day schedule might contribute to the well-being of MS.
Obstructive sleep apnea (OSA) has become major public concern and is continuously investigated in new aspects of pathophysiology and management. Urotensin II (UII) is a powerful vasoconstrictor with ...a role in cardiovascular diseases. The main goal of this study was to evaluate serum UII levels in OSA patients and matched controls. A total of 89 OSA patients and 89 controls were consecutively enrolled. A medical history review and physical examination of the participants was conducted, with polysomnography performed in the investigated group. UII levels and other biochemical parameters were assessed according to the standard laboratory protocols. The median AHI in the OSA group was 39.0 (31.4-55.2) events/h, and they had higher levels of hsCRP when compared to control group (2.87 ± 0.71 vs. 1.52 ± 0.68 mg/L;
< 0.001). Additionally, serum UII levels were significantly higher in the OSA group (3.41 ± 1.72 vs. 2.18 ± 1.36 ng/mL;
< 0.001), while positive correlation was found between UII levels and hsCRP (r = 0.450;
< 0.001) and systolic blood pressure (SPB) (r = 0.317;
< 0.001). Finally, multiple regression analysis showed significant association of UII levels with AHI (0.017 ± 0.006,
= 0.013), SBP (0.052 ± 0.008,
< 0.001) and hsCRP (0.538 ± 0.164,
= 0.001). As UII levels were associated with blood pressure and markers of inflammation and OSA severity, it might play an important role in the complex pathophysiology of OSA and its cardiometabolic complications.
We aimed to investigate the associations between intelligence quotient test scores obtained using the Raven's Advanced Progressive Matrices (APM) and psychomotor testing using the Complex ...Reactionmeter Drenovac (CRD) test battery, while taking into account previous theoretical approaches recognizing intelligent behavior as the cumulative result of a general biological speed factor reflected in the reaction time for perceptual detections and motor decisions. A total of 224 medical students at the University of Split School of Medicine were recruited. Their IQ scores were assessed using Raven's APM, while the computerized tests of CRD-series were used for testing the reaction time of perception to visual stimulus (CRD311), psychomotor limbs coordination task (CRD411), and solving simple arithmetic operations (CRD11). The total test-solving (TTST) and the minimum single-task-solving (MinT) times were analyzed. On the CRD11 test, task-solving times were shorter in students with higher APM scores (r = -0.48 for TTST and r = -0.44 for MinT;
< 0.001 for both). Negative associations between task-solving times and APM scores were reported on CRD311 (r = -0.30 for TTST and r = -0.33 for MinT,
< 0.001 for both). Negative associations between task-solving times in CRD411 and APM scores (r = -0.40 for TTST and r = -0.30 for MinT,
< 0.001 for both) were found. Faster reaction time in psychomotor limbs coordination tasks, the reaction time of perception to visual stimulus, and the reaction time of solving simple arithmetic operations were associated with a higher APM score in medical students, indicating the importance of mental speed in intelligence test performance. However, executive system functions, such as attention, planning, and goal weighting, might also impact cognitive abilities and should be considered in future research.
Introduction
The European Sleep Apnea Database was used to identify distinguishable obstructive sleep apnoea (OSA) phenotypes and to investigate the clinical outcome during positive airway pressure ...(PAP) treatment.
Method
Prospective OSA patient data were recruited from 35 sleep clinics in 21 European countries. Unsupervised cluster analysis (anthropometrics, clinical variables) was performed in a random sample (n=5000). Subsequently, all patients were assigned to the clusters using a conditional inference tree classifier. Responses to PAP treatment change in apnoea severity and Epworth sleepiness scale (ESS) were assessed in relation to baseline patient clusters and at short- and long-term follow-up.
Results
At baseline, 20 164 patients were assigned (mean age 54.1±12.2 years, 73% male, median apnoea–hypopnoea index (AHI) 27.3 (interquartile range (IQR) 14.1–49.3) events·h
−1
, and ESS 9.8±5.3) to seven distinct clusters based on anthropometrics, comorbidities and symptoms. At PAP follow-up (median 210 IQR 134–465 days), the observed AHI reduction (n=1075) was similar, whereas the ESS response (n=3938) varied: largest reduction in cluster 3 (young healthy symptomatic males) and 6 (symptomatic males with psychiatric disorders, −5.0 and −5.1 units, respectively (all p<0.01), limited reduction in clusters 2 (obese males with systemic hypertension) and 5 (elderly multimorbid obese males, −4.2 (p<0.05) and −3.7 (p<0.001), respectively). Residual sleepiness in cluster 5 was particularly evident at long-term follow-up (p<0.05).
Conclusion
OSA patients can be classified into clusters based on clinically identifiable features. Importantly, these clusters may be useful for prediction of both short- and long-term responses to PAP intervention.
To investigate the effect of the coronavirus 2019 (COVID-19) lockdown on lifestyle behaviors and mood changes in the Croatian general population.
During ten days of the COVID-19 lockdown in Croatia, ...3027 respondents (70.3% female) from the general population completed an online, self-report questionnaire. Demographic data and data on lifestyle habits and mood changes before and during the COVID-19 lockdown were collected.
A total of 95.64% of respondents reported to follow most or all restrictions, with female sex (P<0.001) and higher education level (P<0.001) being associated with higher restriction compliance. Women smoked an increased number of cigarettes (P<0.001). The proportion of respondents of both sexes who did not drink or drank 7 drinks per week or more increased (P<0.001). Women also reported lower frequency (P=0.001) and duration of physical exercise (P<0.001). In total, 30.7% of respondents gained weight, with female sex (OR, 2.726) and higher BMI (OR, 1.116; both P<0.001) being associated with an increased likelihood of gaining weight. Both men and women felt more frequently afraid (P<0.001), discouraged (P<0.001), and sad (P<0.001).
Public health authorities should promote the adoption of healthy lifestyles in order to reduce long-term negative effects of the lockdown.
Summary
Obstructive sleep apnoea (OSA) is characterized by periods of upper airway collapse accompanied by repeated episodes of hypoxia. In experimental animals repeated bouts of hypoxia may evoke ...sustained augmentation of phrenic nerve activity, known as phrenic long‐term facilitation (pLTF). This form of physiological compensation might contribute to stable breathing, minimizing the occurrence of apnoeas and/or hypopnoeas during sleep in patients with OSA. Serotonin (5‐HT) has been shown to modulate respiratory neuronal activity, possibly via projections originating in the raphe nuclei. Our model focuses on the effects of 5‐HT1A receptors blockade by selective antagonist WAY‐100635 into the caudal raphe region on phrenic long‐term facilitation after exposure to acute intermittent hypoxia (AIH) episodes. Adult, male, urethane‐anaesthetized, vagotomized, paralyzed and mechanically ventilated Sprague–Dawley rats were exposed to AIH protocol. Experimental group received microinjection of WAY‐100635 into the caudal raphe nucleus, whereas the control group received saline into the same site. Peak phrenic nerve activity and respiratory rhythm parameters were analysed during five hypoxic episodes, as well as at 15, 30 and 60 min after the end of hypoxias. In the control group, 1 h post‐hypoxia pLTF was developed. Microinjections of selective 5‐HT1A receptor antagonist WAY‐100635 into the raphe nuclei prior to the AIH protocol prevented induction of pLTF. These results suggest that 5‐HT1A receptor activation at supraspinal level is important for induction of pLTF, which is suggested to be an important respiratory neuroplasticity model in animal studies that possibly correlates with OSA in humans.
Summary
It is unknown to what extent chronic intermittent hypoxaemia in obstructive sleep apnea causes damage to the motor and sensory peripheral nerves. It was hypothesized that patients with ...obstructive sleep apnea would have bilaterally significantly impaired amplitudes of both motor and sensory peripheral nerve‐evoked potentials of both lower and upper limbs. An observational study was conducted on 43 patients with obstructive sleep apnea confirmed by the whole‐night polysomnography, and 40 controls to assess the relationship between obstructive sleep apnea and peripheral neuropathy. All obstructive sleep apnea subjects underwent standardized electroneurographic testing, with full assessment of amplitudes of evoked compound muscle action potentials, sensory neural action potentials, motor and sensory nerve conduction velocities, and distal motor and sensory latencies of the median, ulnar, peroneal and sural nerves, bilaterally. All nerve measurements were compared with reference values, as well as between the untreated patients with obstructive sleep apnea and control subjects. Averaged compound muscle action potential and sensory nerve action potential amplitudes were significantly reduced in the nerves of both upper and lower limbs in patients with obstructive sleep apnea compared with controls (P < 0.001). These results confirmed that patients with obstructive sleep apnea had significantly lower amplitudes of evoked action potentials of both motor and sensory peripheral nerves. Clinical/subclinical axonal damage exists in patients with obstructive sleep apnea to a greater extent than previously thought.
The aim of this cross-sectional study was to objectively assess the salivary flow rate and composition and periodontal inflammation in obstructive sleep apnoea (OSA) patients. The subjects, who ...underwent whole-night polysomnography or polygraphy, were referred for saliva sampling and periodontal examination. According to the severity of OSA based on the Apnoea Hypopnea Index (AHI) value, the subjects were classified into groups: no OSA (AHI < 5; N = 17), mild to moderate OSA (AHI 5-29.9; N = 109), and severe OSA (AHI > 30; N = 79). Salivary flow rate, pH, salivary electrolytes, and cortisol were measured from collected saliva samples. Periodontal examination included assessment of the number of teeth, dental plaque, bleeding on probing and periodontal measurements: gingival recession, probing pocket depth, clinical attachment level (CAL) and periodontal inflamed surface area (PISA) score. There were no significant differences in salivary flow rate, salivary pH, salivary electrolyte concentrations or electrolyte ratios among the groups classified according to the severity of OSA. However, subjects without OSA had higher salivary cortisol concentrations than OSA groups (p < 0.001). Increased plaque scores were associated with a higher AHI (r = 0.26; p = 0.003). According to the salivary flow rate, subjects with hyposalivation and reduced salivation had higher concentrations of salivary electrolytes and lower salivary pH than subjects with normal salivation. Subjects with hyposalivation had an increased Mg/PO
ratio (p < 0.001) and a reduced Ca/Mg ratio (p < 0.001). Furthermore, subjects with severe OSA tended to have higher CALs and plaque volumes. In conclusion, under pathological conditions, such as OSA, multiple interactions might impact salivary flow and electrolyte composition. Complex interrelationships might affect the integrity of oral health, especially considering OSA severity, inflammation, concomitant diseases and medications.
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