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Biomedical subjects

K Tambs

Publications and source records attributed to K Tambs.

49 records · Page 3Linked to original sources
PubMed1992

[Sexual abuse of children--a public health problem?].

Owing to variation in the reported prevalences of sexual abuse of children, international publications were reviewed to analyse the definitions and other criteria used. Reported prevalences varied from 4 to 67 per cent, the variation being due, among other things, to inconsistency in the definitions used. By some of the investigators sexual acts without actual physical contact between the offender and the victim had been included in the category, exhibitionism. Approximately half of the reported experiences were isolated events. Future research in this field will require greater conformity in the definitions and criteria used.

Adolescent↗
PubMed1991

Pedigree analysis of Eysenck Personality Questionnaire (EPQ) scores in monozygotic (MZ) twin families.

MZ twins with spouses and children, altogether 811 subjects, completed the Eysenck Personality Questionnaire (EPQ). For extraversion (E), neuroticism (N), and lying (L), models including only additive genetic effects fitted well to the observed sex-specific correlations for the various sets of relationships. There was no evidence of sex differences for any parameter estimate for E, N, and L. The fit for E improved significantly after including dominance, and the fit for L improved significantly after including assortative mating. A model specifying genetic additive and dominance effects and assortative mating fitted well to the Psychoticism (P) data, but the fit improved significantly when a parameter for cultural transmission from fathers to daughters were included. Except for this, there was no evidence of cultural transmission for any scores. The heritabilities for the best-fitting models were .53 (E), .36 (N), .43 (L), and .39 (P). The latter includes almost only nonadditive, and no additive, variance, suggesting an overestimation of this effect due to random fluctuation or environmental sibling effect misinterpreted as dominance.

Adult↗
PubMed1991

Transmission of symptoms of anxiety and depression in nuclear families.

Anxiety and depression symptom scores from the SCL-90 questionnaire were observed in a large sample of nuclear families, and the effects of genes or family environment were estimated. Assuming no environmental transmission from parents to offspring, heritability was estimated at 0.43 for both anxiety and depression scores, and common sibling environment or reciprocal sibling influence explained 19% of the variances for both scores. Most of the (genetic or environmental) family effect seemed to be common for the two scores. There was no evidence of common determinants in the family for the symptom scores and alcohol consumption, not even of any substantial relationship within persons between symptoms and consumption. The spouse correlations were 0.25 for anxiety and 0.38 for depression. Similar values for the correlations between anxiety in one person and depression in his/her spouse implies a mate selection based on a single latent variable to which the two observed traits contribute.

Adult↗
PubMed1990

Hypertension labelling, life events and psychological well-being.

Almost all previous studies of the psychological sequelae of hypertension labelling have lacked a prospective, longitudinal design which could allow for causal interpretations. The present study relies on questionnaire data from a hypertension screening carried out on the entire adult population of a medium-sized, Norwegian county (total number of participants = 74977). 'Labelled' individuals, i.e. previously unaware hypertensives (N = 173), false positives (N = 233), and patients in need of continued BP control (N = 474) have been followed up after 1-3 years, and comparisons are made with aware hypertensives (N = 206), patients previously treated for hypertension (N = 118), and a random sample of normotensives (N = 2326). 'Pre-labelling', baseline measures of subjective well-being had been carried out on all comparison groups in connection with the screening. Changes in psychological well-being are not significantly related to labelling or BP-status. However, there is a deterioration in psychological well-being among participants who have been subjected to one or more negative life events/stresses (other than labelling) in the preceding 12 months.

Adaptation, Psychological↗
PubMed1990

Alcohol consumption in parents and offspring: a study of the family correlation structure in a general population.

Alcohol consumption was recorded for 2390 spouses and 498 children of age 18 or above living with their parents. The spouse correlation was 0.67, whereas parent-offspring and sibling correlations were all close to 0.35. This family correlation structure implies an upper limit for heritability of 0.44. The design does not permit a separation of effect of cultural (environmental) and genetic transmission in families, but comparisons with previous heritability analyses suggest that heritability is in fact close to the upper limit, implying little or no cultural transmission. There were virtually no correlations between alcohol consumption and symptoms of anxiety and depression. Nor did consumption correlate substantially with symptoms in first-degree relatives. These results do not support hypotheses of common genetic nor even of common environmental determinants for alcohol consumption and mental disorders.

Adolescent↗
PubMed1989

Genetic and environmental contributions to the covariance between occupational status, educational attainment, and IQ: a study of twins.

Scores of occupational status, educational attainment, and IQ were obtained for 507 monozygotic and 575 dizygotic male twin pairs born 1931-1935 and 1944-1960. A multivariate genetic analysis with statistics from different cohorts showed heterogeneity between cohorts, and analyses were performed in four separate cohorts. The only set of results which departed clearly from the rest was found for the group born 1931-1935, where the ratio of environmental to genetic effects exceeded those of the other groups. Typical heritability values in the three youngest groups (weighted means) were .43, .51, and .66 for occupation, education, and IQ, respectively. The values in the oldest group were .16, .10, and .37, but this sample is small and the estimates are unstable. Genetic variance influencing educational attainment also contributed approximately one-fourth of the genetic variance for occupational status and nearly half the genetic variance for IQ. The values for the between-families variances (reflecting family environment and assortative mating) varied from 2 to 35% in the three youngest groups but were higher for education (62%) and IQ (45%) in the oldest groups. All the between-families variance was common to all three variables. For educational attainment and IQ, the bulk of this between-families variance is probably genetic variance due to assortative mating. The common-factor environmental within-family variances were generally small, and the specific estimates seemed to contain mainly measurement error.

Achievement↗
PubMed1987

Left-handedness in twin families: support of an environmental hypothesis.

Information on handedness, assessed as writing-hand, was collected from 197 MZ twin pairs and 203 DZ twin pairs and from their parents, spouses, and children. Associations for pairs of relatives were studied by 2 X 2 tables, computing chi squared-values and tetrachoric correlations. Correlations of about .3 were obtained for mother-offspring and sibling pairs, while for cousins the correlation was .25 (in a small sample). No other significant associations were found, not even for twins. These results suggest only a small, if any, genetic effect, and only a small environmental between family effect, most of which seems to be a maternal effect. The lack of cotwin correlations and correlations for one of the twins with her/his ordinary brothers/sisters suggest the existence of an effect specific to twins, since the correlation for pairs of ordinary siblings is significant. Conclusions drawn from twin studies alone may be biased. The frequency of left-hand writers has increased from 1% to 10% in the different age groups born during the last century in Norway. This age effect is present mainly in hand writing and not so much in handedness generally, suggesting a decrease in cultural repression against left-hand writing.

Adult↗
PubMed1985

Cotwin closeness in monozygotic and dizygotic twins: a biasing factor in IQ heritability analysis?

For 98 pairs of MZ twins, four measures indicating degree of cotwin closeness were correlated with absolute differences between IQ scores within pairs. In two different twin samples (40 MZ vs 40 DZ pairs and 169 MZ vs 174 DZ pairs, respectively), means and standard deviations in the closeness variables were obtained for MZ and DZ pairs. Whereas MZ cotwins were clearly closer than DZ cotwins, the relation between cotwin closeness and similarity in IQ seemed rather weak and ambiguous. "Years lived together in childhood home" were positively related to similarity in IQ (P less than 0.01), whereas subjective feeling of closeness in contact tended to be negatively related to similarity in IQ.

Adult↗
PubMedDate not supplied

A twin study of personality disorders.

No twin study has previously investigated the whole range of personality disorders (PDs) recorded by interviews. Based on twin and patient registries, 92 monozygotic (MZ) and 129 dizygotic (DZ) twin pairs were interviewed with the Structured Clinical Interview for DSM-III-R Personality Disorders (SCID-II). Observed prevalence rates from a normal population study of more than 2,000 individuals were used in combination with data from the present study to generate statistics assumed to be valid for a normal twin population, and these statistics were used for structural equation modeling. The best-fitting models had a heritability of .60 for PDs generally, .37 for the eccentric (A) cluster, .60 for the emotional (B) cluster, and .62 for the fearful (C) cluster. Among the specific PDs, the heritability appeared to be .79 for narcissistic, .78 for obsessive-compulsive, .69 for borderline, .67 for histrionic, .61 for schizotypal, .57 for dependent, .54 for self-defeating, .29 for schizoid, .28 for paranoid, and .28 for avoidant PDs. The best-fitting models never included shared-in-families environmental effects. However, a model with only shared familial and unique environmental effects could not be ruled out for dependent PD. Shared familial environmental effects may also influence the development of any PD and borderline PD. Passive-aggressive PD did not seem to be affected by genes or family environment at all. The low occurrence of antisocial PD in the twin sample precluded any model for this disorder. PDs seem to be more strongly influenced by genetic effects than almost any axis I disorder, and more than most broad personality dimensions. However, we observed a large variation in heritability among the different PDs, probably partly because of a moderate sample size and low prevalence of the specific disorders.

Adult↗
PubMedDate not supplied

The Nord-Trøndelag Norway Audiometric Survey 1996-98: unscreened thresholds and prevalence of hearing impairment for adults > 20 years.

As supplement to a general health screening examination (HUNT-II), we conducted a puretone audiometry study in 1996-98 on adults (>20 years) in 17 of 23 municipalities in Nord-Trøndelag, Norway, including questionnaires on occupational and leisure noise exposure, medical history, and symptoms of hearing impairment. The study aims to contribute to updated normative hearing thresholds for age and gender, while evaluating the effects of noise exposure, medical history, and familial or genetic influences on hearing. This paper presents the unscreened hearing threshold data and prevalence of hearing impairment for different age groups and by gender. Valid audiometric data were collected from 62% (n=50,723) of 82,141 unscreened invited subjects (age-range 20-101 years, mean=50.2 years, SD=17.0 years). Two ambulant audiometric teams each conducted 5 parallel self-administered, pure-tone hearing threshold examinations with the standard test frequencies 0.25-0.5-1-2-3-4-6-8 kHz (manual procedure when needed). Tracking audiometers were used in dismountable booths with in-booth noise levels well within ISO criteria, except being at the criterion around 200 Hz. The data were electronically transferred to a personal computer. Test-retest correlations for 99 randomly drawn subjects examined twice were high. The mean thresholds recorded were some dB elevated from "audiometric zero" even for age group 20-24 years. As also found in other studies, this might indicate too restrictive audiometric reference thresholds. Males had slightly better hearing < or =0.5 kHz for all age groups. Mean thresholds were poorer in males > or = 30 years from > or =2 kHz, with maximal gender differences of approximately 20 dB at 3-4 kHz for subjects aged 55-74 years. Weighted prevalence data averaged over 0.5-1-2-4 kHz showed hearing impairment >25 dB hearing threshold level of 18.8% (better ear) and 27.2% (worse ear) for the total population--for males 22.2% and 32.0%, for females 15.9% and 23.0%, respectively. Mean hearing loss > or =10 dB at 6 kHz registered for both genders even in age groups 20-24 years may be partly due to calibration artefacts, but might possibly also reflect noise-related socio-acusis.

Adult↗