Biomedical subjects

K Tambs

Publications and source records attributed to K Tambs.

At least 19 recordsLinked to original sources

PubMed2006

Subjective well-being: genetic and environmental contributions to stability and change.

BACKGROUND: Previous cross-sectional studies have found substantial genetic influences on individual variation in subjective well-being (SWB), and evidence for sex-specific genetic effects has been reported. However, the genetic and environmental influences on stability and change in SWB over time are largely unexplored. METHOD: Questionnaire data on SWB from a population-based sample of Norwegian twins born 1967 to 1979, initially surveyed in 1992 (T1) and re-surveyed in 1998 (T2), were analysed using structural equation modelling to explore the relative effects of genetic and environmental influences on phenotypic stability and change. RESULTS: The phenotypic cross-time correlations for SWB were 0.51 and 0.49 for males and females respectively. The best-fitting longitudinal model specified only additive genetic and individual environmental effects with qualitative and quantitative sex-specific genetic influences. For both males and females, the additive genetic factors influencing SWB were largely stable, although some time-specific genetic contributions were indicated. Cross-time correlations for genetic effects were 0.85 and 0.78 for males and females respectively. The individual environmental influences were primarily time-specific. Additive genetic effects explained approximately 80% of the phenotypic cross-time correlation. For females, the magnitude of the additive genetic effects decreased significantly from T1 to T2, whereas for males, the estimates generally remained unchanged. CONCLUSIONS: For both males and females, long-term stability of SWB was mainly attributable to stable additive genetic factors, whereas susceptibility to change was mostly related to individual environmental factors. However, both stable environmental contributions and emerging genetic influences were indicated.

Attitude to Health↗

PubMed2005

Psoriasis in Norway as observed in a population-based Norwegian twin panel.

BACKGROUND: Psoriasis is a chronic T-cell-mediated immunological skin disease. The occurrence of the disease appears to differ with geography and ethnicity. There is a need for epidemiological data obtained from defined population-based studies, and the sex-specific differences observed in the natural history of the disease require more attention. OBJECTIVES: To describe the occurrence and risk of psoriasis in Norway by age and sex. PATIENTS/METHODS: A population-based health survey was conducted in 1998 in Norwegian twins aged 19-31 years. The present study is based upon the self-reported history of psoriasis among the 8045 questionnaire responders. RESULTS: Altogether, 334 (4.2%) reported a positive history of psoriasis. There were no sex differences in the overall prevalence rates, but significantly higher point-prevalences emerged in females in the teenage-year intervals. A fairly linear increase in incidence rates by every 4-year age-interval peaked at a lower age in females. The mean age at onset was also significantly lower in females (14.8 years) than in males (17.3 years). The absolute risk of developing psoriasis appeared higher for females across the entire age range. However, by the age of 31 the cumulative risks were similar in females and males (0.056 and 0.053, respectively). CONCLUSIONS: In this historical cohort of Norwegian twins, we find a high prevalence of psoriasis in congruence with previously reported data among whites in north-western Europe. We have found sex-specific characteristics in point-prevalences and incidence rates which may contribute to the understanding of the earlier age at onset of the disease in females.

Adult↗

PubMed2004

Depression during pregnancy and after delivery: a repeated measurement study.

The aim of this study was to examine the risk of depression in the postpartum period (first four months after delivery) as compared to the remaining postnatal year and the pregnancy period. All postpartum women from two municipalities in Norway were included in a questionnaire study of mental health (n = 416). Over 50% of the women (n = 259) answered an identical questionnaire at an additional time either before or after the postpartum period. The level of depression was measured by the Edinburgh Postnatal Depression Scale (EPDS) and the Hopkins Symptom Check List-25 items (SCL-25). The point prevalence of depression (EPDS> or =10) in the first four months postpartum did not differ significantly as compared to other time periods during pregnancy and the postnatal year. This finding remained also after controlling for other risk factors of depression; high score on the life event scale, prior depression and poor partner relationship. There was a non-significant trend of lower prevalence of depression during early pregnancy and after the first eight postnatal months. In conclusion, our findings suggest that the first four months postpartum were not distinguished by higher depression prevalence as compared to other time periods during pregnancy and the first postnatal year.

Adult↗

PubMed2003

Gender differences in binge-eating: a population-based twin study.

OBJECTIVE: To assess whether genetic and environmental effects on liability to binge-eating (BE) are of equal importance for males and females and whether the same genetic risk factors predispose to BE in the two sexes. METHOD: Questionnaire data on 8045 same sex and opposite sex twins, aged 19-31 years, from a population-based Norwegian registry, was used to estimate the relative contribution of genetic and environmental factors to liability for BE utilizing structural equation modeling. RESULTS: In the best-fitting model, the magnitude of genetic and environmental effects on BE was the same for males and females. Heritability was 51%. The correlation between genetic risk factors in men and women was estimated to be +0.57. CONCLUSION: Binge-eating appears to be equally heritable in males and females. Although the majority of the genetic risk factors are shared between the sexes, there may exist gender-specific genetic effects on liability.

Adult↗

PubMed2002

Back-neck pain and symptoms of anxiety and depression: a population-based twin study.

BACKGROUND: Clinical and epidemiological studies have shown an association between anxiety and depression and pain in the back and neck. The nature of this relationship is not clear. This study aimed to investigate the extent to which common genetic and environmental aetiological factors contribute to the covariance between symptoms of anxiety and depression and back-neck pain. METHODS: Measures of back-neck pain and symptoms of anxiety and depression were part of a self-report questionnaire sent in 1992 to twins born in Norway between 1967 and 1974 (3996 pairs). Structural equation modelling was applied to determine to what extent back-neck pain and symptoms of anxiety and depression share genetic and environmental liability factors. RESULTS: The phenotypic correlation between symptoms of anxiety and depression and back-neck pain was 0.31. Individual differences in both anxiety and depression and back-neck pain were best accounted for by additive genetic and individual environmental factors. Heritability estimates were 0.53 and 0.30 respectively. For back-neck pain, however, a model specifying only shared- and individual environmental effects could not be rejected. Bivariate analyses revealed that the correlation between back-neck pain and symptoms of anxiety and depression was best explained by additive genetic and individual environmental factors. Genetic factors affecting both phenotypes accounted for 60% of the covariation. There were no significant sex differences. CONCLUSION: The results support previous findings of a moderate association between back-neck pain and symptoms of anxiety and depression, and suggest that this association is primarily due to common genetic effects.

Adolescent↗

PubMed2002

Depression in postpartum and non-postpartum women: prevalence and risk factors.

OBJECTIVE: The aim of the study was to assess the prevalence of depression in postpartum women as compared with non-postpartum women, and to identify risk factors of depression in both groups. METHOD: A population based questionnaire study was performed among women 18-40 years in two municipalities in Norway in 1998-1999. A total of 2,730 women were included, of whom 416 were in the postpartum period. RESULTS: The prevalence of depression was higher in non-postpartum as compared with postpartum women. High scores on the life event scale, a history of depression and a poor relationship to the partner were associated with depression in both postpartum and non-postpartum women. When controlling for the identified risk factors of depression the odds-ratio for depression in the postpartum period was 1.6 (95% CI: 1.0-2.6). CONCLUSION: The risk for depression was increased in the postpartum period, when controlling for the uneven distribution of risk factors.

Adult↗

PubMed2002

Child related strain and maternal mental health: a longitudinal study.

OBJECTIVE: To explore how normal age-related behaviour patterns and medical status affect maternal mental health in children aged 1.5-4 years. METHOD: Data were collected via questionnaires from a population-based sample. Outcome variable was the Hopkins Symptom Checklist (HSCL-25). Multiple regression analyses were used to assess the extent to which changes in the predictors (sociodemographic variables, chronic strains, negative life events, maternal somatic health and social support) explained changes in maternal distress. RESULTS: Changes in strain related to children and child care-taking predicted changes in maternal mental distress stronger than the other explanatory variables. Only effects of changes in child care-taking were significant for both time periods. CONCLUSION: Changes in maternal symptoms of anxiety and depression appear to be influenced by changes associated with children's behaviour, their medical status and child care-taking arrangements.

Adult↗

PubMed2001

Review of validation studies of the Edinburgh Postnatal Depression Scale.

OBJECTIVE: To review validation studies of the Edinburgh Postnatal Depression Scale (EPDS). METHOD: A systematic search was performed in Medline and the Science Citation Index Expanded (ISI) from the period 1987-2000. For sensitivity and specificity of the EPDS presented in each study, 95% confidence intervals were estimated. Positive and negative predictive values were estimated assuming prevalences of postpartum depression ranging from 5% to 20%. RESULTS: Eighteen validation studies were identified. The study design varied between studies. The sensitivity and specificity estimates also varied: 65-100% and 49-100%, respectively. The confidence intervals were estimated to be wide. Our estimates suggest a lower positive predictive value in a normal population than in the validation study samples. CONCLUSION: Most studies show a high sensitivity of the EPDS. Because of the differences in study design and large confidence intervals, uncertainty remains regarding the comparability between the sensitivity and specificity estimates of the different EPDS versions.

Confidence Intervals↗

PubMed2001

The Edinburgh Postnatal Depression Scale: validation in a Norwegian community sample.

This study was undertaken to validate a Norwegian translation of the Edinburgh Postnatal Depression Scale (EPDS). The EPDS was validated against the DSM-IV criteria for major depression, derived from the PRIME-MD, in an interview study of 56 women selected from a community-based questionnaire study of 310 women 6 weeks postpartum. A score of > or =10 on the EPDS scale identified all women with major depression, giving a sensitivity of 100% (95% confidence interval; 72%-100%) and a specificity of 87% (95% confidence interval; 77%-95%). The EPDS scores were strongly correlated with the Montgomery-Asberg Depression Rating Scale in the subsample of women interviewed (n=56) and with the Hopkins Symptom Check List (SCL-25) scores in the questionnaire study (n=310). Our results with regard to the sensitivity and specificity estimates are comparable with prior validation studies; however, the confidence intervals around the estimates are wide. Nevertheless, this study confirms that the EPDS is a valid clinical screening instrument for detecting postpartum depression.

Adult↗

PubMed2001

Becoming a disability pensioner with rheumatoid arthritis in Norway 1971-1990.

OBJECTIVE: Physically demanding occupations have been associated with becoming a disability pensioner with rheumatoid arthritis (DPRA), but not with the disease of RA. The association with becoming DPRA probably reflects that patients with RA have difficulties in maintaining employment in a physically demanding occupation. However, the attitudes of the employers concerning employment of persons with RA might vary. For example, the patient's age may influence the strength of the association between a physically demanding occupation and becoming DPRA. We assessed whether the association between the predictors and becoming DPRA was stronger for the youngest or the oldest age group. METHODS: The study was prospective with data on persons in Norway 30-56 years old either in the census of 1970 or 1980. All new cases of DPRA during the 2 followup periods 1971-80 and 1981-90 were identified and analyzed by logistic regression. RESULTS: For women the predictors employment, low level of education, and period ( 1981-90 compared to 1971-80) were more strongly associated with becoming DPRA for the youngest compared to the oldest persons, while manual work and part time work were not predictors of becoming DPRA. For men, all the predictors in the study were more strongly associated with becoming DPRA for the youngest compared to the oldest age group. CONCLUSION: The higher risk of becoming DPRA was associated with most predictors for persons aged 30-39 years than the group aged 50-56 years. Our results appear to indicate that the consequences of having RA in the labor market are greater for the youngest age group.

Adult↗

PubMed2000

Socioeconomic factors and disability retirement from back pain: a 1983-1993 population-based prospective study in Norway.

STUDY DESIGN: A prospective observational study with an 11-year follow-up period was performed. OBJECTIVE: To investigate the influence of education and socioeconomic position on the incidence of permanent disability retirement from back pain. SUMMARY OF BACKGROUND DATA: Early retirement because of back pain is the extreme end point of a disabling process that is a great burden to the individual and costly for the society. Groups of employees at particular risk for permanent back pain disability need to be identified. METHODS: All employed men and women in Norway between the ages of 20 and 53 years in 1980 were included (n = 1,333,556). Outcome measures were disability retirement from inflammatory back pain (ICD-9 code 720) and noninflammatory back pain (ICD-9 codes 721 to 724). RESULTS: The 11-year cumulative incidence was 0.15% (n = 1990) for disability retirement from inflammatory back pain and 1. 64% (n = 21,829) for noninflammatory back pain and was somewhat higher in women than in men. Each year of formal education was independently associated with decreased risk for disability retirement from noninflammatory back pain (odds ratio [OR] = 0.78; 95% confidence interval [CI] = 0.77-0.79) and from inflammatory back pain (OR = 0.83; 95% CI = 0.81-0.86). Whereas disability from inflammatory back pain was moderately associated with socioeconomic status, there was a consistent upward trend in the association between disability retirement from noninflammatory back pain and lower socioeconomic position. The OR for unskilled workers was 3.1 (95% CI = 2.6-3.7) for men and 2.1 (95% CI = 1.7-2.5) for women, as compared with that of higher professionals. Stepwise analyses suggest that the effect of education is not mediated by socioeconomic status. CONCLUSIONS: The consistent upward trend in the relation of disability retirement to lower levels of education and socioeconomic position, even for inflammatory back pain, shows that factors related to the occupational and social environment play an important role in the disabling process. The stepwise, monotonic relation between socioeconomic position and disability retirement from back pain, even at the higher end of the socioeconomic scale, suggests that the relation between social class and back pain disability cannot be explained solely in terms of manual versus nonmanual jobs.

Adult↗

PubMed2000

Symptoms of anxiety and depression among mothers of pre-school children: effect of chronic strain related to children and child care-taking.

BACKGROUND: Factors that affect maternal mental health were studied when the children were 30 and 50 months old, and changes in the importance of these factors over time were analyzed. A specific aim was to elucidate the role of chronic strain related to children and child care-taking. This study follows up previous work on the influence of social class, strain and social support on maternal mental distress when the children were 18 months old. METHODS: The sample is population based, and 1,081 parents were invited to fill out questionnaires. Maternal mental distress was measured by the Hopkins Symptom Checklist (SCL-25). Multiple regression analyses were conducted at each time point and chi-square tests were used to analyze the changes between the estimated regression coefficients over time. RESULTS: Chronic strain related to children and child care-taking consistently predicted maternal mental distress. Among the specific child related strains, problems with child care-taking were significantly associated with maternal symptom levels at all time points. The importance of two specific child problem behaviors (activity level and the child being a worrier) on maternal mental health changed over time. LIMITATIONS: Conclusions about causality can not be drawn based on cross-sectional analyses. The self-report measures used here may be biased by the current mood state. CONCLUSIONS: Problems with child care arrangements and combining work and child care-taking are predictive of maternal mental health when the children are 18, 30 and 50 months old. The risk and protective factors found here may have implications for prevention and intervention.

Adult↗

PubMed2000

Manual work as predictor for disability pensioning with osteoarthritis among the employed in Norway 1971-1990.

BACKGROUND: Manual work is reported to be a risk factor for becoming a disability pensioner due to osteoarthritis. This association may be due to covariation with other variables. We wanted to assess if manual work remained a risk factor after adjusting for number of hours worked, income, level of education, gender and marital status, and if the risk associated with manual work was equal in the 1970s and the 1980s. METHODS: In a prospective study, data on all new disability pensioners with osteoarthritis in Norway during the two follow-up periods, 1971-1980 and 1981-1990, were analysed by logistic regression. The study include data on all subjects living in Norway and registered as 50-56 years old and employed either in the census collected in 1970 or in the census of 1980. RESULTS: Manual workers have nearly twice the probability of becoming a disability pensioner with osteoarthritis compared to professionals after adjusting for part-time work, income, level of education, marital status and gender. Adjusted for other risk factors, the probability of becoming a disability pensioner with osteoarthritis was three times higher in the 1980s compared to the 1970s. CONCLUSION: The relatively strong association between manual work and disability pensioning with osteoarthritis suggests difficulties in adjusting manual work patterns for a person with osteoarthritis, which may have increased during the study period as implied by the separate effect of the 1980s.

Persons with Disabilities↗

PubMed1999

[What can twin research reveal about the causes of diseases?].

The purpose of this paper is to describe the place of twin studies in etiological research on somatic diseases, using asthma as an example. Twin studies provide answers to the relative importance of genes and environment in the development of disease, but have been criticised for systematic biases especially linked to unusual conditions in twin pregnancies. For asthma, classical twin studies show that genes explain the largest part of the interindividual variability, and that common family environment does not explain similarity in asthma in siblings. The assumptions underlying classical twin studies are discussed. A few other twin designs are mentioned, and we conclude that twin studies still play an important role in understanding causes of somatic diseases.

Asthma↗

PubMed1999

Life stress, social support and psychological distress in late adolescence: a longitudinal study.

Questionnaire data from 211 adolescents and follow-up data recorded 18 months later were employed to test main effects and stress-buffering effects of negative life events, on-going stressors and social support from family and friends on mental health. Negative life events, change from baseline level of on-going adversities and social support all contributed significantly to subsequent symptom scores, although negative life events only reached borderline significance among boys. There was evidence in favour of the buffer hypothesis for boys: negative life events had a significantly stronger effect when social support from peers was low, and long-lasting adversities had a significantly stronger effect when social support from parents was low. Both these two-way interaction effects among boys were significantly different from the corresponding trends among girls. Since the scores on both the independent and dependent variables are based on subjective self-reports, the results may have been affected by various types of response bias. The probabilities of such bias effects are discussed.

Adaptation, Psychological↗

PubMed1999

The influence of social class, strain and social support on symptoms of anxiety and depression in mothers of toddlers.

BACKGROUND: The aim of the study was to identify risk and protective factors for anxiety and depression among mothers of toddlers. METHODS: A population-based sample of 921 Norwegian mothers with 18-month-old children completed a questionnaire designed to examine the impact of socioeconomic and demographic factors, somatic health problems, negative life events, chronic strain and social support on symptoms of anxiety and depression (HSCL-25). RESULTS: There was a moderate aversive effect of negative life events and chronic strain and a moderate protective effect of social support on the symptom level, but no interaction effects were found between the risk and protective factors. Behaviour problems among the children clearly seemed to affect the mothers' symptom level. The symptom level varied with background factors like the mothers' education, employment status and age even after controlling for the effect of strain and social support. The largest effect of the background factors seemed to be indirect, however, mediated through their effect on the risk and protective factors. CONCLUSIONS: Although problems with the children's behaviour and child care arrangements were observed to have a strong impact on the mothers' symptom level, the frequencies of such problems appeared to be less dependent on socioeconomic conditions than did other types of strain.

Adult↗

PubMed1999

Prevalence of parentally perceived adverse reactions to food in young children.

A substantial number of parents perceive that their children have adverse reactions to food, but it is well documented that objective assessments agree with only one-quarter to one-half of parentally reported reactions. In order to prevent wrong diagnoses and curtail unnecessary or inadequate diets, primary health care providers need to deal with the parental perception of adverse reactions to food. A description of the prevalence and pattern of parentally perceived adverse reactions to food in children is needed to meet this challenge. The aim of the present study was to estimate the prevalence, incidence and cumulative incidences of parentally perceived adverse reactions to food in children younger than 2 years of age, and to study the duration of the reactions. A population-based cohort of 3623 children born in Norway was followed from birth until the age of two. At 6-month intervals, the parents completed questionnaires regarding the occurrence and type of any reaction to food. Information was available on the outcome measure at all age points for 77.4% of the families and these were used in the analyses; 3.8% of the cohort were entirely lost to follow-up. The cumulative incidence of adverse reactions to food was 35% by age two. Fruits, milk and vegetables accounted for nearly two-thirds of all reported reactions. Milk was the single food item most commonly incriminated, the cumulative incidence being 11.6%. The cumulative incidences of reported reactions to fruits and vegetables were 20.4% and 7.3%, respectively, with citrus fruits, strawberry and tomatoes as the most common food items in these groups. The cumulative incidences were less for food reactions associated with eggs (4.4%), fish (3%), nuts (2.1%) and cereals (1.4%). The duration of the reactions was short - approximately two-thirds of the reactions were not reported again 6 months later. However, the probability of remission depended on the food item concerned, the age at onset of reactions, and whether the reaction had been reported previously or not. Adverse reactions to food are reported by the parents of one-third of children in Norway before the age of two. The most striking feature of this study is the short duration of the food reactions, as approximately two-thirds of the reactions are not reported again 6 months later. Nevertheless, the high frequency of reactions attributable to milk is of concern. Milk is an important part of the Norwegian diet for children, and if removed from the diet its nutritional value is not easily replaced. Further studies are needed to assess the degree to which parents alter the diet of their children based upon perceived reactions to food.

Age Factors↗

PubMed1999

The EAS temperament questionnaire--factor structure, age trends, reliability, and stability in a Norwegian sample.

A population-based sample of Norwegian children aged 18 months (N = 921), 30 months (N = 784), and 50 months (N = 737) was examined with the EAS Temperament Survey (Buss & Plomin, 1984). The factor structure, psychometric properties, and stability estimates of the instrument were assessed. A cross-validation of the temperament factors of Emotionality, Activity, and Shyness show that the covariance structure conforms with the three scales described by Rowe and Plomin (1977) and Boer and Westenberg (1994). When items from the experimental scale of Sociability were included in the analysis, a four-factor solution confirmed the separate usability of this scale as well. The factor structure does not seem to vary substantially with the age of the children. The scores on the four temperament scales show high stability from one time of measurement to the next. Although no strong gender differences were found, there were significant age trends. Emotionality and Shyness increased from 18 to 50 months, while Activity and Sociability decreased. The study confirmed the structure and stability of the EAS over 3 years among young children, providing support for its use with children as young as 18 months.

Age Factors↗