Sleep disorders, sleepiness and traffic safety: a public health menace

Sleep disorders are not uncommon and have been widely reported throughout the world. They have a profound impact on industrialized 24-h societies. Consequences of these problems include impaired social and recreational activities, increased human errors, loss of productivity, and elevated risk of accidents. Conditions such as acute and chronic insomnia, sleep loss, excessive sleepiness, shift-work, jet lag, narcolepsy, and sleep apnea warrant public health attention, since residual sleepiness during the day may affect performance of daily activities such as driving a car. Benzodiazepine hypnotics and zopiclone promote sleep, both having residual effects the following day including sleepiness and reduced alertness. In contrast, the non-benzodiazepine hypnotics zolpidem and zaleplon have no significant next-day residual effects when taken as recommended. Research on the effects of wakefulness-promoting drugs on driving ability is limited. Countermeasures for excessive daytime sleepiness have a limited effect. There is a need for a social awareness program to educate the public about the potential consequences of various sleep disorders such as narcolepsy, sleep apnea, shift-work-related sleep loss, and excessive daytime sleepiness in order to reduce the number of sleep-related traffic accidents.

The reciprocal interaction between sleep and type 2 diabetes mellitus: facts and perspectives

Type 2 diabetes mellitus is a systemic disease characterized by intolerance to glucose and peripheral resistance to insulin. This endocrine disease affects fundamental mechanisms of the central nervous system and jeopardizes the balance of vital functions such as the cardiovascular and circadian rhythm. The increased prevalence of metabolic disorders in our society is aggravated by endemic voluntary postponement of bedtime and by the current sedentary lifestyle, leading to epidemic proportions of obese people. Diabetes and chronic loss of sleep share the fact that both affect millions and one is detrimental to the other. Indeed, sleep deficits have marked modulatory effects on glucose metabolism and insulin sensitivity and foster metabolic syndrome that culminates in sleep disorders like restless syndrome and sleep apnea, which in turn lead to poor sleep quality. We examine the hypothesis that these two worldwide emerging disorders are due to two interlinked cycles. In our paradigm, we establish an intimate relationship between diabetes and sleep disturbances and postulate possible mechanisms that provide support for this conjecture. In addition, we propose some perspectives about the development of the reciprocal interaction between predictor components of metabolic syndrome and sleep disturbances that lead to poor sleep quality. The ability to predict the development and identify or associate a given mode of sleep disturbance to diabetes would be a valuable asset in the assessment of both. Furthermore, major advances in care coupled with healthy lifestyles can ensure a higher quality of life for people with diabetes.

Effect of melatonin administration on subjective sleep quality in chronic obstructive pulmonary disease

Disturbed sleep is common in chronic obstructive pulmonary disease (COPD). Conventional hypnotics worsen nocturnal hypoxemia and, in severe cases, can lead to respiratory failure. Exogenous melatonin has somnogenic properties in normal subjects and can improve sleep in several clinical conditions. This randomized, double-blind, placebo-controlled study was carried out to determine the effects of melatonin on sleep in COPD. Thirty consecutive patients with moderate to very severe COPD were initially recruited for the study. None of the participants had a history of disease exacerbation 4 weeks prior to the study, obstructive sleep apnea, mental disorders, current use of oral steroids, methylxanthines or hypnotic-sedative medication, nocturnal oxygen therapy, and shift work. Patients received 3 mg melatonin (N = 12) or placebo (N = 13), orally in a single dose, 1 h before bedtime for 21 consecutive days. Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI) and daytime sleepiness was measured by the Epworth Sleepiness Scale. Pulmonary function and functional exercise level were assessed by spirometry and the 6-min walk test, respectively. Twenty-five patients completed the study protocol and were included in the final analysis. Melatonin treatment significantly improved global PSQI scores (P = 0.012), particularly sleep latency (P = 0.008) and sleep duration (P = 0.046). No differences in daytime sleepiness, lung function and functional exercise level were observed. We conclude that melatonin can improve sleep in COPD. Further long-term studies involving larger number of patients are needed before melatonin can be safely recommended for the management of sleep disturbances in these patients.

Epworth's sleepiness scale in outpatients with different values of arterial blood pressure

OBJECTIVE: To compare sleepiness scores of the Epworth scale in patients with different levels of arterial pressure when undergoing outpatient monitoring within the context of clinical evaluation. METHODS: A total of 157 patients selected for outpatient monitoring of arterial pressure during hypertension evaluation were divided into 3 groups: group 1 - normotensive; group 2 - hypertensive; group 3 - resistant hypertensive. For analysis, values > or = 11 were considered as associated with respiratory disturbances during sleep. RESULTS: Seventeen (10.8%) patients in group 1, 112 (71.3%) in group 2, and 28 (17.8%) in group 3, which was composed of aged, more severely hypertensive individuals, were analyzed. Groups were similar relative to sex and body mass index, but different in relation to systolic and diastolic pressure levels and age. Despite an absolute difference, no statistically significant difference occurred between Epworth scores and in the proportion of patients with values > or = 11 (5.9% vs. 18.8% vs. 212.4%; P=0.37). Despite the positive association between degree of sleepiness measured with the scale and the severity of the hypertension, no statistical significance occurred following control by age (p=0.18). CONCLUSION: A positive correlation exists between degree of sleepiness and hypertension severity. The absence of a statistical significance shown in the present study could be due to a beta type of error. Instruments that render this complaint into an objective finding could help in the pursuit of an investigation of respiratory disturbances during sleep in more severely hypertensive patients, and should therefore be studied better.

Atrial Fibrillation and Non-cardiovascular Diseases: A Systematic Review

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with an unfavorable prognosis, increasing the risk of stroke and death. Although traditionally associated with cardiovascular diseases, there is increasing evidence of high incidence of AF in patients with highly prevalent noncardiovascular diseases, such as cancer, sepsis, chronic obstructive pulmonary disease, obstructive sleep apnea and chronic kidney disease. Therefore, considerable number of patients has been affected by these comorbidities, leading to an increased risk of adverse outcomes.The authors performed a systematic review of the literature aiming to better elucidate the interaction between these conditions.Several mechanisms seem to contribute to the concomitant presence of AF and noncardiovascular diseases. Comorbidities, advanced age, autonomic dysfunction, electrolyte disturbance and inflammation are common to these conditions and may predispose to AF.The treatment of AF in these patients represents a clinical challenge, especially in terms of antithrombotic therapy, since the scores for stratification of thromboembolic risk, such as the CHADS2 and CHA2DS2VASc scores, and the scores for hemorrhagic risk, like the HAS-BLED score have limitations when applied in these conditions.The evidence in this area is still scarce and further investigations to elucidate aspects like epidemiology, pathogenesis, prevention and treatment of AF in noncardiovascular diseases are still needed.

Breathing disorders in congestive heart failure: gender, etiology and mortality

We investigated the relationship between sleep-disordered breathing (SDB) and Cheyne-Stokes respiration (CSR) while awake as well as mortality. Eighty-nine consecutive outpatients (29 females) with congestive heart failure (CHF; left ventricular ejection fraction, LVEF <45%) were prospectively evaluated. The presence of SDB and of CSR while awake before sleep onset was investigated by polysomnography. SDB prevalence was 81 and 56%, using apnea-hypopnea index cutoffs >5 and >15, respectively. CHF etiologies were similar according to the prevalence of SDB and sleep pattern. Males and females were similar in age, body mass index, and LVEF. Males presented more SDB (P = 0.01), higher apnea-hypopnea index (P = 0.04), more light sleep (stages 1 and 2; P < 0.05), and less deep sleep (P < 0.001) than females. During follow-up (25 ± 10 months), 27% of the population died. Non-survivors had lower LVEF (P = 0.01), worse New York Heart Association (NYHA) functional classification (P = 0.03), and higher CSR while awake (P < 0.001) than survivors. As determined by Cox proportional model, NYHA class IV (RR = 3.95, 95%CI = 1.37-11.38, P = 0.011) and CSR while awake with a marginal significance (RR = 2.96, 95%CI = 0.94-9.33, P = 0.064) were associated with mortality. In conclusion, the prevalence of SDB and sleep pattern of patients with Chagas' disease were similar to that of patients with CHF due to other etiologies. Males presented more frequent and more severe SDB and worse sleep quality than females. The presence of CSR while awake, but not during sleep, may be associated with a poor prognosis in patients with CHF.

Inflammation induced by increased frequency of intermittent hypoxia is attenuated by tempol administration

The levels of serum inflammatory cytokines and the activation of nuclear factor kappa B (NF-κB) and hypoxia inducible factor-1α (HIF-1α) in heart tissues in response to different frequencies of intermittent hypoxia (IH) and the antioxidant tempol were evaluated. Wistar rats (64 males, 200-220 g) were randomly divided into 6 experimental groups and 2 control groups. Four groups were exposed to IH 10, 20, 30, or 40 times/h. The other 2 experimental groups were challenged with IH (30 times/h) plus tempol, either beginning on day 0 (IH30T0) or on day 29 (IH30T29). After 6 weeks of challenge, serum levels of tumor necrosis factor (TNF)-α, intracellular adhesion molecule (ICAM)-1, and interleukin-10 were measured, and western blot analysis was used to detect NF-κB p65 and HIF-1α in myocardial tissues. Serum levels of TNF-α and ICAM-1 and myocardial expression of NF-κB p65 and HIF-1α were all significantly higher in IH rats than in controls (P<0.001). Increased IH frequency resulted in more significant changes. Administration of tempol in IH rats significantly reduced levels of TNF-α, ICAM-1, NF-κB and HIF-1α compared with the non-tempol-treated group (F=16.936, P<0.001). IH induced an inflammatory response in a frequency-dependent manner. Additionally, HIF-1α and NF-κB were increased following IH administration. Importantly, tempol treatment attenuated this effect.

Effect of smoking habits on sleep

To evaluate the effect of smoking habits on sleep, data from 1492 adults referred to the Sleep Institute were accessed and divided into 3 categories of smoking status: current, former and non-smokers. Categories of pack-years (<15 and ≥15) defined smoking severity. The association of smoking status and smoking severity with sleep was analyzed for sleep parameters, especially apnea and hypopnea index (AHI) ≥5, more than 5% of total sleep time (TST) spent with oxyhemoglobin saturation (SaO2) <90%, and arousal index. The arousal index was higher among current (21 ± 17) and former smokers (20 ± 17) than non-smokers (17 ± 15; P < 0.04). Former smokers had a higher percent of TST at SaO2 <90% than non-smokers (9 ± 18 vs 6 ± 13; P < 0.04). Former smokers with pack-years ≥15 compared to <15 exhibited higher AHI (22 ± 24 vs 16 ± 21; P < 0.05) and arousal index (22 ± 19 vs 18 ± 15; P < 0.05). Current smokers with pack-years ≥15 compared to <15 exhibited higher arousal index (23 ± 18 vs 18 ± 16; P < 0.05) and percent of TST at SaO2 <90% (11 ± 17 vs 6 ± 13; P < 0.05). Smoking status and pack-years were not associated with AHI ≥5 on logistic regression analysis, but current smokers with pack-years ≥15 were 1.9 times more likely to spend more than 5% of TST at SaO2 <90% than non-smokers (95%CI = 1.21-2.97; P = 0.005). The variability of arousal index was influenced by gender, AHI and current smokers with pack-years ≥15 (all P < 0.01). Smoking habits seem to be associated with arousal and oxyhemoglobin desaturation during sleep, but not with AHI. The effect was more pronounced in current than former smokers.

Gender and age differences in polysomnography findings and sleep complaints of patients referred to a sleep laboratory

Our objective was to examine the effet of gender on the sleep pattern of patients referred to a sleep laboratory. The data (questionnaires and polysomnographic recordings) were collected from a total of 2365 patients (1550 men and 815 women). The polysomnography permits an objective assessment of the sleep pattern. We included only polysomnography exams obtained with no more than one recording system in order to permit normalization of the data. Men had a significantly higher body mass index than women (28.5 ± 4.8 vs 27.7 ± 6.35 kg/m²) and had a significantly higher score on the Epworth Sleepiness Scale (10.8 ± 5.3 vs 9.5 ± 6.0), suggesting daytime sleepiness. Women had a significantly higher sleep latency than men, as well as a higher rapid eye movement (REM) latency. Men spent more time in stages 1 (4.6 ± 4.1 vs 3.9 ± 3.8) and 2 (57.0 ± 10.5 vs 55.2 ± 10.1) of non-REM sleep than women, whereas women spent significantly more time in deep sleep stages (3 and 4) than men (22.6 ± 9.0 vs 19.9 ± 9.0). The apnea/hypopnea and arousal indexes were significantly higher and more frequent in men than in women (31.0 ± 31.5 vs 17.3 ± 19.7). Also, periodic leg movement index did not differ significantly between genders, but rather differed among age groups. We did not find significant differences between genders in the percentage of REM sleep and sleep efficiency. The results of the current study suggest that there are specific gender differences in sleep pattern.

Shiftworking families: parents' working schedule and sleep patterns of adolescents attending school in two shifts

OBJECTIVE: To explore whether parents' engagement in shift work affects the sleep habits of their adolescent children who attend school in two shifts. METHODS: The data were drawn from an extensive survey of sleep and daytime functioning of adolescents attending school one week in the morning and the other in the afternoon. The participants were 1,386 elementary and high school students (11-18 years old) whose parents were both employed. The data were analyzed using MANOVA, with parents' work schedule, adolescents' gender and type of school as between-subject factors. RESULTS: Parents' working schedule significantly affected the sleep patterns of high school adolescents. When attending school in the morning, adolescents whose parents were both day workers woke up somewhat later than adolescents with one shiftworking parent. In addition, they slept longer than adolescents whose parents were both shift workers. On weekends, adolescents whose parents both worked during the day went to bed earlier than adolescents whose parents were both shiftworkers. They also had smaller bedtime delay on weekends with respect to both morning and afternoon shifts than adolescents for whom one or both parents worked shifts. A significant interaction between parents' working schedule, adolescents' gender and type of school was found for sleep extension on weekends after afternoon shift school. CONCLUSIONS: Parental involvement in shift work has negative effects on the sleep of high school adolescents. It contributes to earlier wake-up time and shorter sleep in a week when adolescents attend school in the morning, as well as to greater bedtime irregularity.

Health, sleep and lack of time: relations to domestic and paid work in nurses

OBJECTIVE: To assess whether reported morbidity and complaints of lack of time and sleep are associated with the burden of professional work and housework among nurses. METHODS: A cross-sectional exploratory study was carried out among female nurses and nurse assistants (N=206) of a public hospital in Rio de Janeiro, Brazil. Data were collected by means of a questionnaire. The prevalence ratio and 95% confidence intervals were estimated. RESULTS: Mean duration of professional work and housework time was 40.4 and 31.6 hours/week, respectively. Long professional working time (over 44 hours/week) were associated with mild emotional disorders (PR=1.37; 95% CI: 1.05-1.80), complaints of lack of time for resting/leisure (PR=1.61; 95% CI: 1.31-1.97), housework (PR=1.48; 95% CI: 1.12-1.97), and childcare (PR=1.99; 95% CI: 1.51-2.63). Long housework time (over 28 hours/week) was associated with lower prevalence of lack of time for childcare (PR=0.62; 95% CI: 0.46-0.84). High housework load was associated with lack of personal time and complaints of varicose veins (PR=1.31; 95% CI: 1.14-1.50 and PR=1.31; 95% CI: 1.08-1.58, respectively). Complaints of varicose veins were also frequent among female nurses with a total work load above 84 hours (PR=1.30; 95% CI: 1.05-1.61), though this group has shown a lower prevalence of arterial hypertension and recurrent headaches (PR=0.35; 95% CI: 0.15-0.83 and PR=0.53; 95% CI: 0.32-0.89, respectively). CONCLUSIONS: Results suggest that both professional and home environments are relevant in the evaluation of work overload on nurses' health and their family and social life. It is stressed the need for instruments for analyzing total workload among female populations.

Sleep, stress and compensatory behaviors in Australian nurses and midwives

OBJECTIVE: To describe sleep, stress and compensatory behaviors in nurses and midwives. METHODS: The study included 41 midwives and 21 nurses working in Australian hospitals between 2005 and 2009. Participation was voluntary. All participants recorded on a daily basis their work and sleep hours, levels of stress and exhaustion, caffeine intake and use of sleep aids for a month (1,736 days, 1,002 work shifts). RESULTS: Participants reported moderate to high levels of stress and exhaustion on 20-40% of work days; experienced sleep disruption on more than 50% of work days; struggled to remain awake on 27% of work days; and suffered extreme drowsiness or experienced a near accident while travelling home on 9% of workdays. Age, perceived sleep duration and work hours were significant predictors of caffeine intake. About 60% of participants reported using sleep aids (about 20% reported taking prescription medications and 44% of nurses and 9% of midwives reported alcohol use as a sleep aid at least once during the study). Stress and workdays were significant predictors of sedative use. Overall, 22% reported being indifferent or mildly dissatisfied with their job. CONCLUSIONS: Sleep problems, high levels of stress and exhaustion and low job satisfaction are prevalent among nurses and midwives. The use of alcohol and sleeping pills as sleep aids, and the use of caffeine to help maintain alertness is also common. Nurses and midwives may use caffeine to compensate for reduced sleep, especially on workdays, and sleeping pills to cope with their daily work-related stress.

Association between sleep quality and quality of life in nursing professionals working rotating shifts

OBJECTIVE To analyze the association between sleep quality and quality of life of nursing professionals according to their work schedules.METHODS A prospective, cross-sectional, observational study was conducted between January and December 2010, with 264 nursing professionals, drawn from 989 subjects at Botucatu General Hospital and stratified by professional category. The Pittsburg Sleep Quality Index and the WHOQOL-bref were administered to evaluate sleep quality and quality of life, respectively. Self-reported demographic data were collected with a standard form. Continuous variables were reported as means and standard deviations, and categorical variables were expressed as proportions. Associations were evaluated using Spearman’s correlation coefficient. The association of night-shift work and gender with sleep disturbance was evaluated by logistic regression analysis using a model adjusted for age and considering sleep disturbance the dependent variable. The level of significance was p < 0.05.RESULTS Night-shift work was associated with severe worsening of at least one component of sleep quality in the model adjusted for age (OR = 1.91; 95%CI 1.04;3.50; p = 0.036). Female gender was associated with sleep disturbance (OR = 3.40; 95%CI 1.37;8.40; p = 0.008). Quality of life and quality of sleep were closely correlated (R = -0.56; p < 0.001).CONCLUSIONS Characteristics of the nursing profession affect sleep quality and quality of life, and these two variables are associated.

Influence of Quality of Sleep on the Nocturnal Decline in Blood Pressure During Ambulatory Blood Pressure Monitoring

OBJECTIVE: To assess the influence of the quality of sleep on the nocturnal physiological drop in blood pressure during ambulatory blood pressure monitoring. METHODS: We consecutively assessed ambulatory blood pressure monitoring, the degree of tolerance for the examination, and the quality of sleep in 168 patients with hypertension or with the suspected "white-coat" effect. Blood pressure fall during sleep associated with a specific questionnaire and an analogical visual scale of tolerance for ambulatory blood pressure monitoring were used to assess usual sleep and sleep on the day of examination. Two specialists in sleep disturbances classified the patients into 2 groups: those with normal sleep and those with abnormal sleep. RESULTS: Fifty-nine (35 %) patients comprised the abnormal sleep group. Findings regarding the quality of sleep on the day of ambulatory blood pressure monitoring as compared with those regarding the quality of sleep on a usual day were different and were as follows, respectively: total duration of sleep (-12.4±4.7 versus -42.2±14.9 minutes, P=0.02), latency of sleep (0.4±2.7 versus 17±5.1 minutes, P<0.001), number of awakenings (0.1±0.1 versus 1.35±0.3 times, P<0.001), and tolerance for ambulatory blood pressure monitoring (8±0.2 versus 6.7±0.35, P=0.035). An abnormal drop in blood pressure during sleep occurred in 20 (18%) patients in the normal sleep group and in 14 (24%) patients in the abnormal sleep group, P=0.53. CONCLUSION: Ambulatory blood pressure monitoring causes sleep disturbances in some patients, and a positive association between quality of sleep and tolerance for the examination was observed.