Sleep and sleep habits from childhood to young adulthood over a 10-year period.

The aim of this epidemiological study was to utilise a cross-sectional as well as a longitudinal approach to examine sleep habits and how they develop in young people in Iceland. The 668 subjects (1-20 years) who responded to a postal survey in 1985 were followed up 5 and 10 years later. The majority of the variance in bedtime and sleep duration was explained by age, but also to a considerable degree by other factors such as residence, season, and year of survey or interaction of these factors. Natural phenomena, such as the diminution of total sleep duration in the first years of life and the tendency for longer sleep on weekends compared to weekdays were confirmed. The lengthening of sleep on weekends was first significant at the age of 9 and was greater among adolescents than young adults. The incidence of daytime sleepiness increased in adolescence, as did napping, at which time their nocturnal sleep time significantly decreased. Over a period of 10 years, a significant shift to earlier wake-up times occurred in children up to 15 years of age, which resulted in a shortened total sleep time. The idea that individual sleep duration is an inherent parameter is supported by the high positive correlation of total sleep time across a 10-year period (r=.73). The present data confirm that Icelandic adolescents (aged 11, 13, and 15) have delayed bedtimes and shorter nocturnal sleep compared to European peers.

Enucleation and evisceration in Iceland 1964-1992. Study in a defined population.

A retrospective study showed that from 1963-1992 200 eyes were enucleated or eviscerated in Iceland. The mean annual age-adjusted incidence per 100,000 population was 2.66, 50% higher for males than females. The mean annual age- and gender-adjusted incidence has decreased; was highest 3.58 per 100,000 for the period 1971-1978, but was 1.76 per 100,000 for the period 1985-1991. The indications were 1) Blind painful eye (92 eyes), 2) Suspicion of malignant neoplasm (49 eyes), 3) Acute trauma (35 eyes), 4) Corneal ulcer (17 eyes), 5) Other (7 eyes). Of blind painful eyes only 12 (6%) were due to neovascular glaucoma. Medical care is self-contained within the country, the incidence for enucleation is decreasing for all categories except malignancy.

Medical risk factors amongst drivers in single-car accidents.

OBJECTIVES: To estimate medical risk factors amongst drivers in single-car accidents with special reference to sleepiness and alcohol abuse. DESIGN: An epidemiological survey by means of multiple-choice questionnaires that were mailed to drivers and a random control group. SETTING: Iceland. SUBJECTS: All drivers in single-car accidents (n = 471) during 1989-91 and a control group from the general population (n = 1000). MAIN OUTCOME MEASURE: Medical health profile and answers to questions concerning sleep disorders and alcohol abuse. RESULTS: Compared to the controls the drivers were younger and there were three times more males. The drivers abused alcohol more often. Chronic disorders such as epilepsy, diabetes mellitus, and cardiac disorders were not over-represented. Altogether, 15.4% claimed that sleepiness had caused their traffic accident, logistic regression analyses revealed that these 'sleepy' drivers more often had alcohol abuse and a history of 'almost falling a sleep whilst driving'. CONCLUSIONS: Compared to controls, drivers in single-car accidents are more likely to be young, male, have a history of sleepiness whilst driving, and also have a history suggestive of alcoholism. Chronic disorders like epilepsy and diabetes mellitus were not over-represented amongst the single-car accidents drivers. These results raise the question of how drivers with a high probability of causing an accident (sleepiness and alcoholism) can be identified in time and proper measures taken to prevent 'accidents waiting to happen'.

Psychopharmacoepidemiology in Iceland: effects of regulations and new medications.

The sale of psychotropic medications in Iceland has waxed and waned during the past 20 years with approximately 5 years between peak and bottom quantities sold. Apparently, it has decreased following restrictions imposed by the public health authorities and increased again following the introduction of new drug. In order to study this further, all prescriptions for psychotropic medications to non-hospitalized inhabitants of the capital city (Reykjavík) and dispensed by pharmacists there during 1 month in 1984, 1989 and 1993 were analysed in order to estimate the 1-month prevalence of psychopharmacological use. The results support the hypothesis partly as prescriptions for tranquillizers decreased in 1989 as well as the amount of tranquillizers and hypnotics prescribed following new restrictions, whereas the prevalence odds ratio of obtaining prescriptions for hypnotics remained unchanged. The proportion of patients receiving excessive amounts of tranquillizers and/or hypnotics decreased. The prevalence of excessive use of these drugs (i.e. > 90 DDD/month) was 0.5% in 1993. In 1993 the prevalence of the use of antidepressants as well as the amount prescribed had increased substantially following the introduction of the new selective serotonin reuptake inhibitor medications. Thus, the prevalence of patients obtaining any psychotropic medication remained unchanged from 1984 to 1993.

[Health-related quality of life.].

INTRODUCTION: With increasing technology in medicine and possibilities to extend life, interest for studying health-related quality of life, i.e. the subjective well-being of patients against the background of their diseases, accidents or treatment, has increased. The purpose of this paper is to introduce a self administered test for health-related quality of life, the IQL (Icelandic Quality of Life), and to show how it differentiates between groups of patients and to encourage the use of such tests in clinical work and research. The reliability and validity of the IQL has been shown to be acceptable. METHOD AND MATERIAL: The IQL had 30 questions and visual analogue items which measure 11 aspects of health-related quality of life. Raw scores for each subscale and for the total test are transformed into T-scores in order to make results easily comparable. The test was administered to a total of 219 persons in four groups of patients and disabled. RESULTS: The test differentiates the more severely ill and disabled persons from the less severely ill. Each subscale except pain differentiates the groups from each other, showing a specific profile for each group. There is a high correlation between health and social aspects of the test as well as between health and satisfaction with life and well-being. The health-related quality of life of alcoholics was lowest in this study. DISCUSSION: The test can be used, both in research and clinical work, in spite of the fact that the current version of it has not been tried out in a representa nottive sample of the population. The test is included in an appendix. CONCLUSION: Health is of major importance for the quality of life. Health-related quality of life needs to be studied in order to evaluate the patients fully and their need for health service as well as its effects.

Period prevalence rates of specific mental disorders in an Icelandic cohort.

This paper presents the 1-month, 6-month and 1-year prevalence rates for mental disorders in a random sample of people born in Iceland in 1931 and interviewed at the age of 55-57 years. The diagnoses were made according to DSM-III, on the basis of the National Institute of Mental Health's Diagnostic Interview Schedule (DIS) used by trained lay interviewers. The period prevalence rates were found to be similar to those obtained by other studies using the DIS as a survey instrument. The highest rates were among the widowed, separated or divorced. The 1-year symptom-free rates were high for alcohol abuse and alcohol dependence, 74% and 71%, respectively. For depressive disorders, the 1-year symptom-free rate was only 50% and for the anxiety disorders, 50%-65%. The most common psychiatric disorders had a chronic course.

Snoring, hypertension, and the sleep apnea syndrome. An epidemiologic survey of middle-aged women.

The lower limit of the prevalence of sleep apnea syndrome (SAS) was estimated among women 40 to 59 years old by a two-stage procedure. In the first stage 2,016 questionnaires were mailed. The response rate was 75.6 percent. Daytime sleepiness was reported by 8.2 percent, habitual snoring by 11.2 percent, and intermittent snoring by 21.7 percent. There were altogether 128 women described with systemic hypertension and these women were more than twice as often habitual snorers. Logistic multiple regression analyses showed almost a threefold increase in the predicted prevalence of hypertension among intermittent and habitual snorers compared with nonsnorers in the age group 40 to 49 years old and a 60 percent increase in the 50- to 59-year-old age group. In the second stage, a group of 97 women highly suspected of SAS were selected because of their habitual snoring and daytime sleepiness. Eventually, 35 of these came for night studies and 14 were found to have SAS. Among the 35 women, 12 were hypertensive and nine of these had SAS. We estimated the lower limit of the prevalence of SAS to be 2.5 percent for women 40 to 59 years old. It is concluded that SAS is a relatively common occurrence among women, especially postmenopausal ones, and it is strongly related to hypertension.

Lifetime prevalence of specific mental disorders among people born in Iceland in 1931.

The lifetime prevalence rates are presented for mental disorders in a random sample of people born in Iceland in 1931, interviewed at the age of 55-57 years. The diagnoses are made according to DSM-III, on the basis of the National Institute of Mental Health's diagnostic Interview Schedule (NIMH-DIS) used by trained lay interviewers. The most common diagnoses were alcohol abuse and dependence, generalized anxiety disorder, phobic disorders, dysthymic disorder and major depressive episode. Disorders more common in men were antisocial personality, alcohol abuse and alcohol dependence. Disorders more common among women were major depressive episode and generalized anxiety disorder. Alcohol abuse was more prevalent among those living in rural areas, but dependence was more prevalent in the urban area, where panic disorder is also more frequent. Widowed, separated and divorced people had most of the highest prevalences: tobacco-use disorder, alcohol abuse and dependence, dysthymia and generalized anxiety disorder. Except for a very high rate of alcohol abuse and dependence and a low rate of substance abuse disorders, the prevalence rates are similar to those obtained in North American studies using the NIMH-DIS as a survey instrument. The DSM-III criteria for alcohol abuse or dependence may be less applicable to Iceland than to North America, because of differences in what is culturally regarded as acceptable use of alcohol.

Effects of L-tryptophan on daytime arousal.

A double-blind placebo-controlled study was carried out on 20 subjects to examine the early morning sedative effects of 2 g of L-tryptophan. Using brain mapping technique, 16-channel EEG recordings were topographically displayed. A distinct increase in theta amplitude, predominantly in the central region, together with an alpha reduction was observed after L-tryptophan administration, signs characterizing the EEG of drowsiness. Subjective self-rated sleepiness increased after the ingestion of L-tryptophan. Psychomotor performance, assessed by means of various psychometric tests, was not affected by this low dose of L-tryptophan.