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Biomedical subjects

M Koskenvuo

Publications and source records attributed to M Koskenvuo.

At least 127 records · Page 7Linked to original sources
PubMed1996

Alzheimer's disease in Finnish twins.

BACKGROUND: The genetics of Alzheimer's disease (AD) are obscure. Although most cases are sporadic half the patients with sporadic AD have a positive family history. The mode of genetic transmission and the role of environmental factors are unknown. The purpose of this study was to examine the contribution of genetic factors to the pathogenesis of AD in a twin cohort. METHODS: The Finnish Twin Cohort consists of all Finnish same-sexed twin pairs born before 1958 with both co-twins alive in 1975. The total number of twin pairs is 13 888, of whom 4307 are monozygotic (MZ) and 9581 ar dizygotic (DZ). These data were linked with the Hospital Discharge Register from 1972 to 1991 to identify twins who had dementia or related disease as a discharge diagnosis. The linkage of the registries yielded a total of 285 twin individuals. The medical records of these twins and their co-twins were reviewed to confirm and classify dementia (AD, vascular dementia, mixed dementia, and other dementia). The incidence, concordance, and age at onset of AD were examined. FINDINGS: The incidence of AD was significantly higher in MZ than in DZ twin individuals, with and adjusted MZ/DZ incidence ratio of 1.8 (95% confidence intervals 1.2 to 2.7). In contrast, the incidence of vascular or mixed dementia did not differ between MZ and DZ individuals (MZ/DZ ratio 0.6 [0.3 to 1.2]) for vascular and 1.0 [0.5 to 2.1] for mixed dementia). The pairwise concordance for AD was 18.6% in MZ pairs and 4.7% in DZ pairs and the corresponding probandwise concordance rates were 31.3% and 9.3%. The pairwise concordance for vascular dementia was 18.2% in MZ pairs and 6.7% in DZ pairs with corresponding probandwise rates of 30.8% and 12.5%. The onset age of AD concordant MZ pairs was identical in two pairs and diverged by up to 15 years. INTERPRETATION: The higher incidence of AD in MZ individuals than in DZ individuals may provide a clue to the aetiology of AD. The higher concordance rate of MZ pairs confirms the contribution of the major genetic component while indicating the need to identify environmental triggers.

Age of Onset↗
PubMed1996

Interpersonal conflict as a predictor of work disability: a follow-up study of 15,348 Finnish employees.

This 6-year follow-up study investigates the impact of interpersonal conflict at work on work disability among 8,021 male and 7,327 female employees aged 24 to 65 years at baseline. Marital status, marital conflict, monotonous work, hectic work pace, hostility, neuroticism, life dissatisfaction, and experienced stress of daily activities were included in survival analyses, which were adjusted for age, social status, and general health status. Interpersonal conflict at work predicted work disability only among women (RR 1.56, CL 1.01-2.39). This risk was confined to women who reported simultaneous marital conflicts (RR 2.54, CL 1.03-6.22). When included in further analyses, life dissatisfaction was a significant risk factor among both genders, but monotonous work, neuroticism, and experienced stress of daily activities were risk factors only among men. These data suggest that interpersonal conflict could be a determinant of work disability, and this indicates the importance of gender and marital factors.

Adult↗
PubMed1996

Recent interpersonal conflict at work and psychiatric morbidity: a prospective study of 15,530 employees aged 24-64.

Relationships between psychiatric morbidity and interpersonal conflict at work among 15,530 Finnish employees aged 24 to 64 years were studied in a prospective follow-up: 4 years for all psychiatric hospitalizations, 5 years for suicide, and 6 years for long-term medication due to chronic psychosis. The association between interpersonal conflict at work and physician-diagnosed psychiatric morbidity was significant (RR 2.18, 95% CI 1.34-3.54) when results were adjusted for general health status, social class, and mental instability/stress. Results remained significant in additional models adjusted for neuroticism, marital status, conflict with spouse, and high alcohol consumption. The results were similar for both sexes.

Adaptation, Psychological↗
PubMed1996

Daytime sleepiness in an adult, Finnish population.

OBJECTIVES: To investigate the prevalence of and the factors associated with daytime sleepiness occurring every or almost every day. DESIGN: A cross-sectional, questionnaire survey. SUBJECTS: A total of 11,354 adults (aged 33-60 years) representative of the Finnish population. MAIN OUTCOME MEASURES: Frequency of daytime sleepiness, naps and sleep attacks; occurrence of emotion-associated muscle weakness, sleep debt, insomnia, sleep apnoeas and type of snoring; Beck Depression Inventory score; and the use of hypnotics and tranquillisers. RESULTS: A total of 11.0% of women and 6.7% of men suffered from daytime sleepiness every or almost every day. Amongst those with sleepiness (n = 1,026) 19.5% of women and 42.3% of men reported snoring > or = 3 nights per week, 25% had scores suggesting moderate to severe depression, 11% used hypnotics or tranquilizers on more than 180 days per year, and 9% reported insufficient sleep. Insomnia at least every other day was reported by 20.7% of women and by 28.6% of men. Amongst those with sleepiness, narcolepsy was found in 0.3%, with the diagnosis confirmed in a sleep laboratory evaluation. CONCLUSIONS: Daytime sleepiness occurring daily or almost daily is most often associated with depression, insomnia and sleep-disordered breathing. In most cases, indications of the cause of sleepiness can be obtained by using simple screening questions.

Adult↗
PubMed1996

Narcolepsy-like symptoms among adult twins.

The genetic architecture of narcolepsy is poorly known. Genetic and environmental components of symptoms characteristic of narcolepsy, excessive sleepiness and cataplexy were assessed in a population-based sample of middle-aged like-sexed twin pairs. Questionnaire assessment of the 11-item Ullanlinna Narcolepsy Scale (UNS), a validated screening instrument for narcolepsy [J. Sleep Res. (1994) 3, 52-59] and two subscales (sleepiness and cataplexy-like symptoms) was obtained from both twins of 3785 pairs aged 33-60 y (541 male MZ pairs, 1089 male DZ pairs, 781 female MZ and 1374 female DZ pairs) from the population-based Finnish Twin Cohort. For the UNS scores, the intraclass correlation for male MZ pairs was 0.365 and for male DZ pairs 0.072, while for female pairs the MZ correlation was 0.375 and for DZ pairs 0.155. Structural equation model fitting indicated that a model with additive and non-additive genetic effects, and idiosyncratic environmental effects best accounted for the pattern of twin resemblance in both men and women. Genetic effects accounted for 35% (in men) and for 39% (in women) of total phenotypic variance in UNS. Analysis of the subscales suggested that there may be a greater genetic component to the sleepiness subscale, while environmental components play more of a role in the development of cataplexy-like symptoms. Further investigation of the complex genetic architecture of narcolepsy and its symptoms is warranted.

Adolescent↗
PubMed1996

Total and occupationally active life expectancies in relation to social class and marital status in men classified as healthy at 20 in Finland.

STUDY OBJECTIVE: To study differences in total life expectancy and in occupationally active life expectancy in relation to social class and marital status in men classified as healthy as young adults. DESIGN: Historical cohort study. SETTING: Finland. PARTICIPANTS: Altogether 1662 men classified as completely healthy at the time of induction to military service (mean birth year 1923), who had been selected as referents for a study of former athletes. Mean follow up time was 46 years. MEASUREMENTS: Vital status was determined by follow up through local parish data up to 1990. Mortality data were obtained from the Cause of Death bureau of the Central Statistical Office of Finland. Occurrence of work disability was assessed from nationwide disability pension register data. Mean total life expectancy and mean occupationally active life expectancy (end points disability pension or death before age 65 years) were estimated. Social class was based on the major lifetime occupation, while marital status was classified as "never married" or "ever married" at the end of follow up. MAIN RESULTS: Mean total life expectancy was highest among executives and managers (73.2 (95% confidence interval (CI): 70.3, 76.1) years), next highest in clerical (white collar) workers (72.0 (70.0, 74.1) years), and lowest in unskilled blue collar workers (63.65 (61.1, 66.2) years). Skilled workers and farmers were intermediate. For the occupationally active life expectancy estimates, a similar gradient was observed: highest for executives (61.9 (60.7, 63.1) years) and lowest for the unskilled (52.2 (50.2, 54.2) years). The ratio of occupationally active life expectancy to total life expectancy was highest for executives (85%) and lowest for farmers (81%) and unskilled workers (82%). CONCLUSIONS: The social class gradient known to exist for mortality is also present for occupational disability. Social class and marital status differences in mortality are already evident in early adulthood and continue into old age. Those with the highest life expectancy also have the largest proportion of their life span free of occupationally incapacitating disability.

Adult↗
PubMed1996

Asthma and other pulmonary diseases in former elite athletes.

BACKGROUND: The prevalence of asthma is rising and there are recent reports of increasing asthma rates among top level skiers and runners in the Nordic countries. METHODS: The lifetime occurrence of pulmonary diseases (asthma, chronic bronchitis, emphysema) and current bronchitis symptoms was compared in former elite male athletes (n = 1282) who represented Finland between 1920 and 1965 at least once in international competitions and controls (n = 777) who, at the age of 20, were classified as healthy and who responded to a questionnaire in 1985. The presence of disease and symptoms was identified from the questionnaire and, in the case of asthma, also from a nationwide reimbursable medication register. The death certificates of the subjects of our original cohort who died between 1936 and 1985 were also investigated to determine the cause of death. RESULTS: The occurrence of the pulmonary diseases was associated with age, smoking habits, occupational group, and a history of exposure to chemicals. After adjusting for these variables, athletes who participated in mixed sports (odds ratio (OR) 0.46, 95% confidence interval (CI) 0.23 to 0.92) and power sports (OR 0.43, 95% CI 0.21 to 0.87) had lower odds ratios for emphysema, and endurance sports athletes had a lower odds ratio for the presence of at least one pulmonary disease (OR 0.53, 95% CI 0.28 to 0.98) when compared with controls. Athletes also tended to have fewer reimbursable medications for asthma and fewer current symptoms for chronic bronchitis. Between 1936 and 1985 two controls but none of the athletes died of asthma. CONCLUSIONS: The lifetime occurrence of asthma or other pulmonary diseases is not increased in former elite athletes, and exercise alone, even in a cold environment, did not appear to increase the prevalence of asthma, at least up to the mid 1980s.

Asthma↗
PubMed1996

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.

Adipose Tissue↗
PubMed1996

The heritability of body mass index among an international sample of monozygotic twins reared apart.

BACKGROUND: Published heritability estimates (h2) for body mass index (BMI) range from as low as 0.05 to as high as 0.90. The purpose of this paper is to introduce new data to help narrow the range of plausible estimates. SUBJECTS: Subjects were 53 pairs (23 M; 30 F) of monozygotic twins reared apart (MZAs), whose mean BMI was 24.2 (SD = 4.7). BMI's were transformed to approximate normality via the Box-Cox transformation. Twin paris came from the Finnish Twin Cohort (17 pairs), a data base of Japanese twins (10 pairs) and published case histories of primarily American twins (26 pairs). RESULTS: The h2 for MZAs is given by the correlation among the twin pairs. For the transformed data, the zero-order correlation of twins' BMIs was 0.79 for all twins, 0.63 for the Finnish twins, 0.73 for the Japanese twins and 0.85 for the 'archival' twins. When modeled with regression to control for relevant covariates, the estimate of h2 is either 0.50 or 0.70, depending on one's definition. The semipartial r was 0.50, suggesting that 50% of the total variance in BMI appears to the genetic in origin after controlling the covariates. The partial r was 0.70, suggesting that 70% of the variance in BMI that is not accounted for by the covariates can be attributed to genetic variation. Separation age had a small positive correlation with absolute intra-pair difference in BMI, suggesting that these estimates of h2 are not biased upwards due to early shared environment. CONCLUSIONS: Findings are consistent with past studies of MZAs and suggest that h2 estimates between 0.50 and 0.70 are reasonable. Implications of this finding are discussed.

Adult↗
PubMed1995

Residential exposure to magnetic fields generated by 110-400 kV power lines in Finland.

In a specific case, the magnetic field generated in a building by a nearby power line is usually easy to calculate, although the accuracy of these calculations is sensitive to the quality of source information. To be able to study public health dimensions of magnetic field exposure (e.g., risk of cancer), it is necessary to evaluate the size and exposure of the population at risk. Relatively little quantitative information on public exposure to power-frequency magnetic fields of high-voltage power lines is available. This report describes residential exposure to magnetic fields from 110 kV, 220 kV, and 400 kV power lines in Finland at the national level, including 90% of the total line length in 1989. A geographical information system (GIS) was used to identify the buildings located near the power lines. After determining the distances between the lines and the buildings, historical data on load currents of these lines were used to calculate the magnetic fields. The residential magnetic field histories were then linked to the residents by means of a computerized central population register. The data obtained on personal exposure have also been utilized in a nationwide epidemiological study on magnetic field exposure of power lines and risk of cancer. The methods of exposure assessment and results of the number of buildings near 110 kV, 220 kV, and 400 kV power lines, their average annual magnetic fields, and personal exposure to magnetic fields from these lines are described. We found that 15,600 residents lived in an average residential magnetic field > or = 0.1 microT caused by power lines in 1989. The number of these residents increased fivefold during 1970-1989. We estimated that 0.3% of the population was exposed in their residences to an annual average magnetic flux density from 110 kV, 220 kV, and 400 kV power lines higher than 0.1 microT, the level that the background magnetic flux density in general does not exceed in Finnish homes. Thus, the problem of magnetic field exposure generated by high-voltage lines concerns only a relatively small fraction of the total population in Finland. However, the size and exposure of the population at risk remain somewhat arbitrary in practical multisource situations, as the biological interaction mechanism, the concept of harmful dose, and, in particular, the significance of the duration of exposure are unknown.

Child↗
PubMed1995

Migraine and concomitant symptoms among 8167 adult twin pairs.

We studied the inheritance of migraine and concomitant symptoms among 2690 monozygotic (1524 female and 1166 male) pairs and 5497 dizygotic (2951 female and 2546 male) twin pairs. Our material consists of a population-based questionnaire study among Finnish twins in 1981. The definition of migraine is based on a questionnaire method. Concordance was assessed using probandwise concordance rates and tetrachoric correlations for monozygotic (MZ) and dizygotic (DZ) twin pairs. For estimating the contribution of genetic factors to the susceptibility of migraine, a polygenic multifactorial model was used. Structural equation models were applied for estimating variance components and to compare different genetic models. Nearly one-half (40% to 50%) of the liability to migraine is attributable to genetic factors. In all structural analyses, the model with both additive genetic and unshared environmental component had the best goodness-of-fit value. The genetic component varied between 34% to 51% in different migraine types. There were no remarkable differences between sexes except in the effects due to dominance, where the proportion was 26% for men and 14% for women. Concomitant symptoms among subjects within pairs concordant for headache had genetic effects varying from 56% (subjects with unilaterality) and 56% (subjects with visual symptoms) to 45% (persons with nausea and vomiting). The two threshold model of headache points to the continuum model of headache, and the thresholds represent different levels of severity of the pain. Our results emphasize a multifactorial and higher than previously reported genetic pattern in the etiology of migraine. Also unshared environmental factors play an important role.

Diseases in Twins↗
PubMed1995

Atopy: a predisposing factor for chronic bronchitis in Finland.

STUDY OBJECTIVE: To investigate the predictive value of atopy, smoking, and living in a farm environment in the development of chronic bronchitis. DESIGN: This was a cross sectional and longitudinal study. SETTING: Postal surveys carried out in Finland in 1975 and 1981. PARTICIPANTS: The study was part of the Finnish twin cohort study, which included adult twin pairs born in Finland before 1958. The cross sectional sample consisted of 18,351 subjects, including 1025 prevalent cases, and the follow up sample comprised 17,134 subjects, 553 of whom were incident cases of chronic bronchitis. MAIN RESULTS: According to the cross sectional data, chronic bronchitis was associated with atopy (relative risk 1.41) and smoking (2.43). In the follow up data, chronic bronchitis was related to atopy (1.28), smoking (2.31), and farming (1.45). CONCLUSIONS: The results confirm the earlier finding in the Finnish farming population that, in addition to smoking, atopy predisposes the development of chronic bronchitis. A farm environment was also found to be a predisposing factor. The results give further support to the "Dutch hypothesis" on the etiology of chronic bronchitis, according to which atopy is a predisposing factor.

Adolescent↗
PubMed1995

Consistency and change of body mass index and weight. A study on 5967 adult Finnish twin pairs.

OBJECTIVE: To study twin resemblance for weight change (delta wt) and to assess the consistency of body mass index (BMI) over 6 years. DESIGN: 6 year follow-up based on identical mailed questionnaires in 1975 (baseline) and in 1981 (follow-up). SUBJECTS: 5967 same-sexed non-pregnant Finnish twin pairs aged 18-54 in 1975 (1106 male and 862 female monozygotic (MZ) and 2430 male and 1569 female dizygotic (DZ) pairs). MAIN OUTCOME MEASURES: Intra-pair correlations of delta wt and BMI, estimates of genetic and environmental components of variance of delta wt and BMI. RESULTS: Unadjusted mean delta wt was +2.0 (s.d. = 4.6) kg among MZ and 2.1 (4.9) kg among DZ male individuals. Corresponding values among MZ and DZ female individuals were +1.5 (4.4) kg and +1.7 (4.4) kg, respectively. Age and initial BMI together explained 8.0% of the male and 2.3% of the female phenotypic variance of delta wt. The intraclass correlations for delta wt (adjusted for age and initial BMI) for all pairs were 0.29 and 0.07 for MZ and DZ men and 0.25 and 0.05 for MZ and DZ women, respectively. The BMI of the twins increased slightly during the follow-up compared to the baseline values (23.9 (2.7) for MZ and 24.1 for DZ men and 23.0 (3.3) for MZ and 23.2 (3.42) for DZ women). The intra-class correlations for BMI at baseline (0.69 for MZ and 0.34 for DZ men and 0.67 for MZ and 0.29 for DZ women) were almost identical with the correlations at follow-up (0.67 for MZ and 0.32 for DZ men and 0.69 for MZ and 0.29 for DZ women). The intra-class correlations for both BMI and delta wt were consistently higher among pairs living together than among pairs living apart at baseline and at follow-up in both zygosity groups (MZ and DZ). Among pairs living apart at baseline, the longitudinal model for BMI showed that the correlation between genetic effects at baseline and at follow-up was very high (> 0.9 in all age groups among both genders). The correlations for environmental effects ranged from 0.50 to 0.67 during the follow-up period. CONCLUSION: Weight changes in adults over a 6-year period appear to be determined by environmental effects rather than genetic factors. However, the genetic component in BMI is considerable and stable over time. Shared environment is likely to contribute to the resemblance of both delta wt and BMI among adult twin pairs, especially among MZ pairs.

Adolescent↗
PubMed1994

The prevalence of narcolepsy: an epidemiological study of the Finnish Twin Cohort.

We investigated the prevalence of narcolepsy using a well-defined white population previously used for epidemiological investigations: the Finnish Twin Cohort. The Cohort consists of 13,888 monozygotic and dizygotic twin pairs born before 1958. There were 16,179 individuals who participated in the study, with a 77.3% response rate. The study methodology included a questionnaire covering sleep and alertness, the Ullanlinna Narcolepsy Scale (UNS), a scale specifically developed and tested for the study, telephone interviews, and finally, clinical evaluation, polygraphic recording, and HLA blood typing. Seventy-five subjects were selected for telephone interviews and laboratory evaluations based on data from both questionnaires. Five of them were strongly suspected of narcolepsy, but laboratory data identified only 3. All were dizygotic (fraternal) twins discordant for the disease with a negative family history and presence of DR2 DQw1 (i.e., DRw15 DQw6, new World Health Organization classification). The prevalence of narcolepsy in the Finnish population is 0.026% (95% confidence interval, 0.0-0.06). This prevalence is lower than that reported in studies performed without polygraphic recording and is close to that reported in 1945 in the black U.S. population. The tools developed to perform this study, the largest population study of its kind yet performed, can now be used for other population investigations.

Adult↗
PubMed1994

A developmental genetic analysis of adult personality: extraversion and neuroticism from 18 to 59 years of age.

Developmental genetic analyses were conducted on Extraversion (E) and Neuroticism (N) scale scores from nearly 15,000 male and female Finnish twins, ages 18-53 at baseline, who were tested on 2 occasions, 6 years apart. Significant genetic effects on both traits were found, at all ages, in men and women, on each measurement occasion. For E, heritability was invariant across sex but decreased from late adolescence to the late 20s, with a smaller additional decrease at about 50 years of age. Heritability for N also decreased from late adolescence to late 20s and remained stable thereafter. For all ages after the early 20s, heritability of N was significantly higher among women. Means for E and N were sex-dependent and, apparently, influenced by cohort and time of assessment, as well as by age. There was little evidence of new genetic contributions to individual differences after age 30; in contrast, significant new environmental effects emerged at every age.

Adolescent↗
PubMed1994

Twin studies in narcolepsy.

The genetic basis of narcolepsy is reflected by the strong association to human leukocyte antigen DR2 (most specifically to DQB1-0602) and the occasional familial occurrence, with several modes of transmission. At present, 12 monozygotic pairs with at least one affected twin have been reported. Of the three pairs considered concordant, the only well-documented pair is DR2 negative. Of the nine discordant pairs five are well documented, and all of these are DR2 positive. We performed a questionnaire study using a validated measure of narcoleptic symptoms (the Ullanlinna narcolepsy scale or UNS). The questionnaire was sent to 2,191 monozygotic twin pairs included in the Finnish Twin Cohort. In 225 pairs neither of the twins responded. In 1,550 pairs both twins responded, but in the answers of 228 pairs there were some missing data concerning the UNS items. Not a single case suggestive of narcolepsy was found. Narcolepsy in monozygotic twins is very rare. These facts support the hypothesis of a multifactorial etiology with a strong influence of nongenetic environmental factors.

Adult↗
PubMed1994

Epidemiology of narcolepsy.

The prevalence of narcolepsy is usually presented at about 50/100,000. There are, however, marked differences of about 2,500-fold between the lowest and the highest reported prevalence. This discrepancy is at least partly explained by differences in the study populations and methods. There are, however, no earlier population-based epidemiological studies with polygraphically confirmed diagnoses. We studied the occurrence of symptoms resembling the two main manifestations of narcolepsy, i.e. abnormal sleep tendency and emotion-associated muscular weakness, in an adult twin cohort (n = 16,179) with a questionnaire. A total of 3.2% met the minimal diagnostic criteria of the International Classification of Sleep Disorders for narcolepsy. Eleven questionnaire items assessing the main manifestations of narcolepsy formed a measure called the Ullanlinna Narcolepsy Scale (UNS), which has been validated. The UNS score was calculated for 11,354 subjects. Those (n = 75) having a UNS score equal or higher than the lowest value in a narcolepsy patient group were studied. Thirty-one of them (fulfilling also the minimal diagnostic criteria) were interviewed, and those suspected of having narcolepsy (n = 5) were evaluated in the sleep laboratory. In three subjects the narcolepsy diagnosis was verified (all dizygotic, nonfamilial and human leukocyte antigen DR2/DQB-0602 positive), giving a prevalence of 0.026% in the adult Finnish (Caucasian) population.

Adult↗