An evaluation of the absolute and relative stability of alexithymia over 11years in a Finnish general population.

OBJECTIVE: We investigated if alexithymia, a personality construct with difficulties in emotional processing, is stable in the general population. METHODS: Altogether 3083 unselected subjects aged 30 and older in Finland completed the 20-item Toronto Alexithymia Scale (TAS-20) in the longitudinal Health 2000 and Health 2011 general population surveys (BRIF8901). The stability of alexithymia at the 11-year follow-up was assessed with t-tests, correlations, and separate linear regression models with base-line and follow-up age, gender, marital status, education, and 12-month depressive and anxiety disorders as confounders. RESULTS: The mean score (SD) of the TAS-20 for the whole sample was 44.2 (10.4) in 2000 and 44.2 (10.9) in 2011 (p=0.731). The mean score of the TAS-20 subscale Difficulty Identifying Feelings increased by 0.3 points, Difficulty Describing Feelings decreased by 0.6 points and Externally Oriented Thinking increased by 0.3 points. The effect sizes of the changes varied from negligible to small. Age had little effect except for the group of the oldest subjects (75-97years): the TAS-20 mean (SD) score was 49.1 (10.1) in 2000 and 53.1 (10.3) in 2011 (p<0.001), the effect size for the increase was medium. TAS-20 score in 2000 explained a significant proportion of variance in TAS-20 score in 2011. Controlling for all baseline confounders improved the model incrementally; the same applied to controlling for confounders at follow-up. Baseline depression or anxiety disorders were not associated with the TAS-20 scores in 2011, whereas current diagnoses were. CONCLUSIONS: According to our large longitudinal study both the absolute and relative stability of alexithymia assessed with the TAS-20 are high in the adult general population.

TRIB1 constitutes a molecular link between regulation of sleep and lipid metabolism in humans.

Epidemiological studies show association between sleep duration and lipid metabolism. In addition, inactivation of circadian genes induces insulin resistance and hyperlipidemia. We hypothesized that sleep length and lipid metabolism are partially controlled by the same genes. We studied the association of total sleep time (TST) with 60 genetic variants that had previously been associated with lipids. The analyses were performed in a Finnish population-based sample (N = 6334) and replicated in 2189 twins. Finally, RNA expression from mononuclear leucocytes was measured in 10 healthy volunteers before and after sleep restriction. The genetic analysis identified two variants near TRIB1 gene that independently contributed to both blood lipid levels and to TST (rs17321515, P = 8.92(*)10(-5), Bonferroni corrected P = 0.0053, ß = 0.081 h per allele; rs2954029, P = 0.00025, corrected P = 0.015, ß = 0.076; P<0.001 for both variants after adjusting for blood lipid levels or body mass index). The finding was replicated in the twin sample (rs17321515, P = 0.022, ß = 0.063; meta-analysis of both samples P = 8.1(*)10(-6), ß = 0.073). After the experimentally induced sleep restriction period TRIB1 expression increased 1.6-fold and decreased in recovery phase (P = 0.006). In addition, a negative correlation between TRIB1 expression and slow wave sleep was observed in recovery from sleep restriction. These results show that allelic variants of TRIB1 are independently involved in regulation of lipid metabolism and sleep. The findings give evidence for the pleiotropic nature of TRIB1 and may reflect the shared roots of sleep and metabolism. The shared genetic background may at least partially explain the mechanism behind the well-established connection between diseases with disrupted metabolism and sleep.

Sleep problems in fibromyalgia and rheumatoid arthritis compared with the general population.

OBJECTIVE: Our aim was to evaluate how frequently problems of quality and quantity of sleep and depression occur in patients with fibromyalgia (FM), and compare these findings with those occurring in patients with rheumatoid arthritis (RA) and in the general population. MATERIALS AND METHODS: The patients were recruited from rehabilitation courses in the Rheumatism Foundation Hospital, Finland. There were 37 patients with FM and 31 patients with RA participating in the study. For comparison, we used the results from a general population study of 1284 adult subjects. The data had been collected earlier in a longitudinal cohort study for the Finnish Social Insurance Institution. RESULTS: The patients with FM and RA slept fewer hours a day than the population sample. The FM patients reported more insomnia, less contentment with sleep and more lack of deep and restful sleep in comparison to the RA patients and the participants of the population study. The FM patients also reported significantly more depression and pain than the RA patients (p0.01). It was still shown in a logistic regression analysis that insomnia was almost five times more frequent in FM patients than in RA patients, even when depression and pain were adjusted. CONCLUSION: The FM patients reported more insomnia-related symptoms than either RA patients or the population sample. The higher prevalence of insomnia-related symptoms among FM patients was not explained by depression or pain. Both patient groups reported somewhat shorter nocturnal sleep than the general population.

Sleep-related disturbances and physical inactivity are independently associated with obesity in adults.

OBJECTIVE: To study relationships between obesity, physical inactivity and sleep-related disturbances (obstructive sleep apnea (OSA), sleep duration, sleep disturbances concomitant with daytime tiredness) in adults (> or =30 years). DESIGN: Cross-sectional study with a random population sample. PARTICIPANTS: A total of 3377 men (mean age 52.3, s.d. 14.8, years) and 4264 women (56.4, s.d. 17.2, years). MAIN OUTCOME MEASURES: Dependent variables, measured: Waist circumference (WC) and body mass index (BMI). Independent variables, from a detailed interview/questionnaire: probable OSA, other sleep-related disturbances, sleep duration, type and frequency of leisure physical activity. Age, mental health, smoking and education were included in analyses as potential confounders. RESULTS: In men, OSA and physical inactivity increased likelihood for abdominal obesity (WC > or =102 cm). Physical inactivity also increased, but long (> or =9 h/day) sleep decreased likelihood for abdominal overweight (WC: 94-101 cm) in men. In women, abdominal obesity (WC > or =88 cm) was associated positively with OSA, moderate sleep-related disturbances, and physical inactivity. Education modulated the influence of age on abdominal obesity in both genders. Using BMI as the dependent variable did not change the general information obtained by the model. In addition, abdominal obesity was found to be an independent risk factor also in multivariable models predicting categories of a combined sleep duration and sleep disturbances. CONCLUSIONS: Sleep duration and sleep-related disturbances are associated with obesity, even after controlling for OSA and physical inactivity. The results support the hypothesis of vicious circle between sleep and obesity.

Visceral fat and psychosocial stress in identical twins discordant for obesity.

OBJECTIVES: Accumulation of intra-abdominal fat has been suggested, but not yet proved, to be basically as a result of chronic psychosocial stress causing arousal of hypothalamic-pituitary-adrenal cortex axis. Our objectives were to study the association between psychosocial stress, obesity and body fat distribution when genetic factors are identical. DESIGN: Monozygotic twins discordant for obesity were examined in an in-patient setting. SUBJECTS: Adult monozygotic twin pairs (12 female, 8 male) with an average intrapair difference of 17 kg in body weight. They were divided into two groups: in group A the visceral fat area of the obese cotwin was higher and, in group B, lower than the gender-specific median value. MAIN MEASURES: Hormonal, physiological and psychological distress indicators, and sleep measures. RESULTS: Daily urinary cortisol and noradrenaline excretion were higher in the obese cotwins when compared with the nonobese cotwins in group A but not in group B (P=0.026 and 0.020 when intrapair differences were compared between groups A and B, respectively). In serum cortisol, ACTH and CBG concentrations a similar trend was not statistically significant. In group A, the obese cotwins consumed almost 2.5 times as much alcohol as their lean cotwins, whilst in group B the situation was the opposite. The mean amount of active sleep was significantly higher and that of quiet sleep significantly lower in the obese than the lean cotwins only in group A. Intrapair differences in emotional reactions indicating distress and lack of subjective energy were seen only in group A. CONCLUSION: When genetic factors are identical, visceral fat accumulation, rather than obesity in general, is associated with increased psychosocial stress and concomitant hormonal changes.

Quality of sleep during economic recession in Finland: a longitudinal cohort study.

To assess the association between the economic recession of the 1990s in Finland and sleep behaviour, a longitudinal study was conducted in an adult Finnish population cohort. Baseline data were obtained by means of reports on sleep behaviour, health-related behaviour, health status, and objective laboratory tests in 1983-1987. The second screening conducted in 1992-1995, i.e. during economic recession, repeated data collection by postal questionnaires. The prevalences of various sleep symptoms including insomnia, daytime tiredness, fatigue, parasomnias and the use of hypnotics remained similar in the same age cohorts during economic recession. Alcohol consumption and snoring increased among the middle-aged (30-49 years), though snoring shows the greatest individual stability among various sleep symptoms. Despite some baseline differences in the sleep/health behaviour frequencies, the changes were independent of gender and socioeconomic class. The prevalences over eight years of insomnia and snoring show fair chronicity, whereas daytime tiredness and fatigue seem to be less chronic. Middle-aged participants who were stably employed at the initial screening but became unemployed during economic recession were studied separately. Prospectively unemployed persons suffered more from insomnia and used more hypnotics than the continuously employed. We conclude that the sleep quality of the general Finnish population has not drastically deteriorated during severe economic recession except among unemployed blue-collar workers.

Electrodermal lability and hypertension.

Thirty-nine (39) middle-aged subjects with mild to moderate hypertension (WHO stages I-II) and 35 healthy normotensive controls from a community sample participated in this psychophysiological study, the aim of which was to study whether the electrodermal lability as an indicator of increased sympathetic activity is related to hypertension. Resting blood pressure was measured by using a mercury sphygmomanometer. Electrodermal activity was recorded with a constant voltage circuit. Bipolar skin electrodes were placed on the palmar side of the middle phalanges of the index and middle fingers of both hands. Six years after the electrodermal measurements, the possible use of reimbursed antihypertensive medication was checked in both groups, and blood pressure re-measured in the control group. Multivariate analysis controlling for age, gender and body mass showed that the electrodermal lability was increased in the hypertensive as compared to the normotensive group. This supports the hypothesis that the sympathetic nervous system tonus is increased at least, in some middle-aged subjects with mild to moderate hypertension.

Sleep in monozygotic twin pairs discordant for obesity.

Nocturnal motor breathing and cardiac activity were recorded by using the static charge-sensitive bed, and sleep habits were studied by questionnaire in 24 pairs of monozygotic twins discordant for their body mass index; the mean intrapair difference between co-twins was 6.7 kg/m2. Intrapair differences in sleep characteristics between co-twins were related to intrapair differences in physiological and anthropometric characteristics. Two questions were tested. First, do monozygotic twins discordant for body mass index differ in sleep behavior? Second, if they do, are differences in sleep associated with nongenetic differences in the body weight and metabolism or with other environmental factors? Obese twins had higher nocturnal motor activity levels, less quiet sleep, and more habitual snoring than did their nonobese co-twins. Differences in sleep were associated with obesity-related factors. However, habitual snoring did not explain other intrapair differences in sleep. It was concluded that relatively moderate obesity is associated with disruption of physiological structure of sleep as measured by the static charge-sensitive bed method and that this disruption seems not to be associated with snoring or breathing disturbances.

What does the multiple sleep latency test measure in a community sample?

Multiple sleep latency test (MSLT)-defined daytime sleepiness and its relationships with nocturnal and daytime psychophysiological activation were investigated in a random community sample of 77 subjects aged 35-55 years. The correlation structure between all study variables was explained by a simple model of daytime sleepiness. The model suggested that indicators of psychophysiological arousal (psychological distress, nocturnal motor activity and serum thyrotropin level) and daytime reported tiredness, body mass index (BMI) and age were related significantly and independently to MSLT-defined daytime sleepiness. The arousal theory of insomnia and poor sleep in relation to MSLT behavior is discussed and the need of a multivariate approach is emphasized in MSLT studies.

Nocturnal breathing abnormalities in acromegaly after adenomectomy.

OBJECTIVE: The incidence of sleep apnoea is increased in acromegaly. The aim of the study was to determine the occurrence of nocturnal breathing abnormalities and upper airway morphology in acromegalic patients some years after adenomectomy. DESIGN: A case-control study. PATIENTS: Eleven patients with treated acromegaly and two control groups: (1) sleep studies: 197 subjects randomly selected from the population, (2) cephalometry: 27 healthy subjects and 17 patients with obstructive sleep apnoea. MEASUREMENTS: Nocturnal breathing was monitored with a static charge-sensitive bed. The upper airway soft tissues and bone morphology were assessed by cephalometric X-ray photography. The upper airway collapsibility was investigated with dynamic nasopharyngoscopy. Endocrinological investigations were also performed. RESULTS: Nocturnal breathing abnormalities were present in all but one acromegalic patient (91%), which was far more frequent than in the general population (29.4%, P < 0.0001). Treated acromegaly was the most powerful predictor of breathing abnormalities, independent of the other significant predictors, age and body mass index. The predominant breathing abnormality was periodic breathing with symmetrically waxing and waning respiratory effort without a major body movement component. Episodes of complete obstruction with repetitive arousals were rare. Except for the longer soft palate, the cephalometric findings were similar to normal. In comparison to obstructive sleep apnoea, the treated acromegalic patients had rather prognathic than retrognathic mandibles. Fibreoptic endoscopy in the acromegalic patients revealed collapsible upper airways at the level of the soft palate, whereas at the base of the tongue little, if any, dynamic narrowing was observed. CONCLUSION: Our study confirms that nocturnal breathing abnormalities are common in treated acromegaly, and may persist years after the removal of the GH secreting tumour. The breathing abnormalities and the upper airway morphology in acromegalic patients after adenomectomy are different from those observed in primary obstructive sleep apnoea, suggesting a different pathophysiology of the airway obstruction.

Nocturnal motor activity in fibromyalgia patients with poor sleep quality.

Nocturnal motor activity was examined in long-term rehabilitation patients complaining of poor sleep and having fibromyalgia syndrome (N = 24) or other musculoskeletal disorders (N = 60) and compared with that in 91 healthy controls drawn from a random community sample. Self-reports on sleep complaints and habits were collected. The frequency of nocturnal body movements, the "apnoea" index and ratio of "quiet sleep" to total time in bed were measured using the Static Charge Sensitive Bed (SCSB) (BioMatt). As a group, patients with fibromyalgia syndrome did not differ from patients with other musculoskeletal disorders or from healthy controls in their nocturnal motor activity. The "apnoea" index was a little higher in the fibromyalgia group than in the healthy control group but did not differ from that of the group of other musculoskeletal patients. Further multivariate analyses adjusted for age, BMI, medication and "apnoea" index did not support the assumption that an increased nocturnal motor activity characterizes patients with fibromyalgia syndrome.

Upper airway obstruction in hypothyroidism.

OBJECTIVES: To determine the occurrence and frequency of nocturnal upper airway obstruction in hypothyroidism. DESIGN: A case-control study of patients with newly diagnosed hypothyreosis and euthyroid subjects who had been selected from the population register. The subjects underwent sleep recordings with a static-charge-sensitive bed (SCSB). SETTING: Turku University Hospital and Research and Development Unit, Social Insurance Institution, Turku, Finland. SUBJECTS: Twenty six consecutive patients underwent sleep recordings with SCSB and a pulse oximeter. One hundred and eighty-eight euthyroid subjects who were previously studied with the SCSB were used as controls. MAIN OUTCOME MEASURES: In a multivariate analysis, hypothyroidism, gender, age, and body mass index (BMI) were considered as predictors for the occurrence of nocturnal breathing abnormalities. RESULTS: Nocturnal breathing abnormalities were frequent in both groups. Fifty per cent of the hypothyroid patients and 29.3% of the control subjects had at least some episodes of partial or complete upper airway obstruction (P = 0.04). Severe obstruction with episodes of repetitive apnoea was present in 7.7% of the patients and in 1.5% of the controls. The multivariate analysis revealed that the presence of hypothyroidism did not significantly (P = 0.06), and independently of age, BMI or gender, predict nocturnal breathing abnormalities, whereas obesity (P < 0.0001) and male gender (P = 0.0001) were independent and significant predictors. CONCLUSIONS: The incidence of nocturnal upper airway obstruction is increased in hypothyroidism, but is related to obesity and male gender rather than to hypothyroidism per se.

Nocturnal motor activity in a community sample.

The relationships between nocturnal motor activity and daytime psychophysiological activation were investigated in a random community sample of 199 subjects aged 35-55 years. Nocturnal motor activity was recorded with the static charge sensitive bed (SCSB, Bio-Matt). The association of nocturnal motor activity with demographic features, health status, laboratory blood values, afternoon electrodermal activity (EDA) and psychological distress was studied. A model for nocturnal motor activity was constructed and statistically analyzed. The analysis revealed that psychological distress, breathing disturbance, plasma glucose level and sympathetic activity were related significantly and independently to nocturnal motor activity. Their relations and the associations of sex, age, body mass index (BMI), sleep latency and health status with nocturnal motor activity were discussed in the context of the arousal theory of poor sleep.

Mental well-being of good sleepers in a random population sample.

It is generally assumed that a good night's sleep has a beneficial effect on mood. The present survey aimed to evaluate what a good night's sleep means for mental well-being and psychic functional capacity. A random community sample of 670 adult subjects was divided into three groups: good, intermediate and poor sleepers according to a sleep habit questionnaire based on self-reports. Their cognitive, emotional and personality features were assessed with various psychometric and personality tests, and differences between the groups were evaluated statistically. In the age- and gender-adjusted population the average good sleeper turned out to be a person who falls asleep in 10 minutes, after which his/her 7.5 hours' sleep is serene and without parasomnias. Immediately on awakening in the morning and later during the day he/she is mentally alert without distress or emotional problems. Definite mood and personality differences between good and other sleepers in the adult population surveyed revealed that good sleepers are psychologically capable of maintaining a self-esteem which is in functional balance with their life-goals and mental well-being.

Quality of sleep and chronic illnesses.

The association between sleep complaints and chronic illnesses was investigated in several patient groups, including type-2 diabetics, patients with recent myocardial infarction, chronic paraplegia, affective disorders or rheumatic (musculoskeletal) disorders. Sleeping habits and complaints were investigated by questionnaire. All diagnoses were established by the rehabilitation team of the Rehabilitation Research Centre (RRC). The prevalence of difficulty in initiating sleep (DIS) and difficulty in maintaining sleep (DMS) was slightly higher in the myocardial infarction group than in their respective matched control group, whereas patients with paraplegia or an affective disorder suffered markedly from various sleep disorders. Patients with rheumatic illness reported sleep disorders significantly less often than patients with affective disorder, though on admission both groups complained of similar somatic symptoms and poor sleep. Organic disease per se does not explain the prevalence of sleep disorders in patients with chronic illnesses. Psychological and social factors seem to contribute significantly to the prediction of sleep disorders in patients with chronic illnesses.

Sleep movements and poor sleep in patients with non-specific somatic complaints--I. No first-night effect in poor and good sleepers.

To evaluate the possible first-night effect on the nocturnal motor activity 25 poor sleepers and 12 good sleepers slept on the Static Charge Sensitive Bed (SCSB) during two consecutive nights. The frequency of body movements in poor sleepers was almost two times higher than in good sleepers. The method itself was reproducible across two nights. There were no statistically significant and systemic level differences between the nights in the movements in bed (MIB). The difference t-test did not either reveal group differences in the magnitude or direction of changes from night to night. Results are consistent with the view that the level of motor activity is one of the determinants of sleep quality. No first-night effect exists in terms of psychomotor activity.

Sleep movements and poor sleep in patients with non-specific somatic complaints--II. Affective disorders and sleep quality.

Nocturnal motor activity of 67 poor sleepers referred to the Rehabilitation Research Centre (RRC) and of 16 healthy subjects were recorded to distinguish poor sleepers without affective disorders from those with affective disorders. All subjects slept on the static charge sensitive bed (SCSB) in a single room of the patient dormitory. All subjects filled out a sleep questionnaire about their subjective sleep quality. After comprehensive rehabilitation consultations the poor sleepers were divided into two subgroups: those with and those without affective disorders. Complaints about insomnia and sleep disorders distinguished poor sleepers from healthy controls but the subgroups of poor sleepers did not differ in the estimation of the quality of sleep. However, when the distribution of body movements through the night was considered, the dynamic of nocturnal motor activity typified poor sleepers with affective symptoms.

Automatic analysis of static charge sensitive bed (SCSB) recordings in the evaluation of sleep-related apneas.

An automatic analysis of Static Charge Sensitive Bed (SCSB) recordings was evaluated in the detecting periodic apneas during sleep. The results of over-night SCSB recordings, on body movements and respiratory movements, were compared with the visually evaluated polygraphic recordings during daytime sleep. Twenty-one patients with obstructive sleep apnea syndrome and 18 controls were studied. The periodic breathing pattern seen in all daytime recordings, was also seen in all output graphs of the over-night SCSB analyses. The automatic analyses revealed periodic breathing in 2 control subjects. The amount was, however, small (less than 4% of the recording time) compared with the high amount observed in the patients with obstructive sleep apneas (mean 42.9% of the recording time). The high sensitivity, easy use, and low cost of the automatic SCSB method make it suitable for the quantification of the periodic breathing during night and for the screening of sleep apneas.