Erkki Kronholm

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.

Does simvastatin affect mood and steroid hormone levels in hypercholesterolemic men? A randomized double-blind trial

Epidemiological and clinical studies have suggested that powerful cholesterol lowering may have adverse effects on mood and psychological well-being. Inhibition of cholesterol biosynthesis by simvastatin (a hydroxymethyl glutaryl coenzyme A reductase inhibitor) may also reduce steroid hormone biosynthesis. To explore if mood changes are related with steroid hormone levels, we designed a randomized double-blind placebo-controlled crossover trial. The separate and combined effects of a Mediterranean-type diet intervention and treatment with simvastatin 20 mg/day PO for 12 weeks were studied in 120 hypercholesterolemic but otherwise healthy middle-aged men. Psychological functioning was assessed with questionnaires, and steroid hormone levels in blood were assayed radioimmunologically before and after the treatments. Simvastatin resulted in a statistically significant increase of depression and somatization without changes in the anxiety, hostility or aggression scores. Mood changes seemed to be unrelated with the statistically significant but clinically insignificant decline in serum testosterone levels and unrelated with the increase in serum dehydroepiandrosterone levels.

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.

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.

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.

Poor sleep among rehabilitation patients

To characterize sleep impairments, we conducted sleep assessments and objective nocturnal activity recordings on 251 consecutive rehabilitation patients with self-perceived poor sleep and on 91 healthy controls. Patients had received referrals to the Rehabilitation Center (RC) of the Social Insurance Institution (Finland) for work capacity assessment. Rehabilitation patients displayed significantly more nocturnal physiological arousal than did healthy controls. No group differences in nocturnal motor activity and apnea index were evident among the patients with mental disorders (N=86), neurological diseases (N=23), cardiovascular diseases (N=12), musculoskeletal disorders (N=86), and other diagnoses (N=44). Affective and anxiety patients with nonspecific somatic complaints reported more insomnia and fatigue than did nonaffective mental patients. However, the former did not differ from other rehabilitation patients in the nocturnal objective measures.