Carsten Obel

Aarhus University, Aarhus, Central Jutland, Denmark

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Publications (124)477.47 Total impact


  • No preview · Article · Jan 2016 · Medicine
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    ABSTRACT: Background: Maternal stress during pregnancy may increase the risk of preterm delivery (PD), but the associations between stress and subtypes of PD are not clear. We investigated maternal loss of a close relative and risks of very and moderately PD (<32 and 32-36 weeks, respectively) and spontaneous and medically indicated PD. Method: We studied 4 940 764 live singleton births in Denmark (1978-2008) and Sweden (1973-2006). We retrieved information on death of women's family members (children, partner, siblings, parents), birth outcomes and maternal characteristics from nationwide registries. Results: Overall, the death of a close family member the year before pregnancy or in the first 36 weeks of pregnancy was associated with a 7% increased risk of PD [95% confidence interval (CI) 1.04-1.10]. The highest hazard ratios (HR) for PD were found for death of an older child [HR (95% CI) 1.20 (1.10-1.31)] and for death of a partner [HR (95% CI) 1.31 (1.03-1.66)]. These losses were associated with higher risks of very preterm [HR (95% CI) 1.61 (1.29-2.01) and 2.07 (1.15-3.74), respectively] than of moderately preterm [HR (95% CI) 1.14 (1.03-1.26) and 1.22 (0.94-1.58), respectively] delivery. There were no substantial differences in the association between death of a child or partner and the risk of spontaneous v. medically indicated PD. Conclusions: Death of a close family member the year before or during pregnancy was associated with an increased risk of PD, especially very PD. Possible mechanisms include both spontaneous and medically indicated preterm birth.
    No preview · Article · Dec 2015 · Psychological Medicine
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    ABSTRACT: Importance Parental death from suicide is associated with increased risk of suicide in the bereaved child, but little is known about the long-term risks of suicide after parental death from other causes. A better understanding of this association may improve suicide prevention efforts.Objective To examine the long-term risks of suicide after parental death and how the risk trajectories differed by cause of parental death while accounting for major potential confounding variables.Design, Setting, and Participants A population-based matched cohort study was performed using information from nationwide registers (data from 1968 to 2008) in 3 Scandinavian countries (for a total of 7 302 033 persons). We identified 189 094 children (2.6%) who had a parent who died before the child reached 18 years of age (ie, the bereaved cohort). Each bereaved child was matched by sex and age to 10 children who did not have a parent who died before they reached 18 years of age (for a total of 1 890 940 children) (ie, the reference cohort). Both cohorts were followed for up to 40 years. Poisson regression was used to calculate the incidence rate ratio (IRR), while accounting for age at parental death, sex, time since bereavement, maternal/paternal death, birth order, family history of psychiatric illness, and socioeconomic status. Data analyses were finalized June 24, 2015.Exposure The main exposure was death of a parent within the first 18 years of life.Main Outcomes and Measures Incidence of suicide among persons who had a parent who died during their childhood.Results During follow-up, 265 bereaved persons (0.14%) and 1342 nonbereaved persons (0.07%) died of suicide (IRR = 2.02 [95% CI, 1.75-2.34]); IRR = 3.44 (95% CI, 2.61-4.52) for children who had a parent who died of suicide, and IRR = 1.76 (95% CI, 1.49-2.09) for children who had a parent who died of other causes. The IRR tended to be higher for children who had a parent who died before they reached 6 years of age, and the IRR remained high for at least 25 years. During 25 years of follow-up, the absolute risk of suicide was 4 in 1000 persons for boys who experienced parental death and 2 in 1000 persons for girls who experienced parental death.Conclusions and Relevance Parental death in childhood is, irrespective of cause, associated with an increased long-term risk of suicide. The consequences of parental death in childhood are far-reaching, and suicide risk trajectories may be influenced by early-life conditions. Future public health efforts should consider helping highly distressed children to cope with bereavement.
    No preview · Article · Nov 2015 · JAMA Psychiatry
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    ABSTRACT: Background: Conventional cohort studies have consistently shown that exposure to maternal smoking in pregnancy is associated with about twice the risk of attention deficit hyperactivity disorder (ADHD) in the offspring. However, recent studies using alternative designs to disentangle the effect of social and genetic confounders have suggested that confounding may account for the association. In this study we aimed to estimate the association by a sibling design. Methods: We used a design with half and full siblings in a Danish national register-based cohort on all singletons born between January 1991 and December 2006 and followed until January 2011. Data were available for 90% (N = 968,665) of the singleton live births in the period. We used the combination of the International Classification of Diseases (10th version) diagnosis of hyperkinetic disorder (HKD) and ADHD medication to identify children. We used sibling-matched (conditional) Cox regression to control social and genetic confounding. Results: Using conventional cohort analyses, we found the expected association between pregnancy smoking and offspring ADHD (adjusted HR 2.01, 95% CI 1.94-2.07). In the sibling analysis, however, we did not detect such a strong association (adjusted HR 1.07, 95% CI 0.94-1.22). There was no difference between results for half- and full sibling analyses. The link between pregnancy smoking and low birth weight remained robust in the sibling design (adjusted OR 1.68, 95% CI 1.33-2.12). Conclusions: We found no support for prenatal smoking as a strong causal factor in ADHD. Our findings suggest that the strong association found in most previous epidemiological studies is likely to be due to a strong link between maternal smoking and maternal ADHD genetics or shared family environment. Pregnant women should still be encouraged to stop smoking because of other risks, but we have no reason to believe that this would reduce the risk of ADHD in the offspring.
    No preview · Article · Oct 2015 · Journal of Child Psychology and Psychiatry
  • Jasveer Virk · Beate Ritz · Jiong Li · Carsten Obel · Jørn Olsen
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    ABSTRACT: Background: Death of a close family member such as a parent or a sibling can cause prolonged stress and changes in the family structure that may have extensive social and health effects on a young child. The aim of this paper is to examine the rate of type 1 diabetes following bereavement due to death of a first-degree family member in early life. Methods: We used data from the Danish Civil Registration System (CRS) to identify singleton births in Denmark born 1 January 1980 through 31 December 2005, n = 1 740 245 and their next of kin. We categorised children as exposed to bereavement if they lost a mother, father or sibling from age 5 years onwards, the remaining children were considered unexposed. Children were followed until first diagnosis of diabetes, death, emigration, or 31 December 2010. We estimated incidence rate ratios (IRRs) from birth using log-linear Poisson regression models with person-years as an offset variable. Exposed children were followed up for an average of 9.1 years [standard deviation (SD) 6.7] and unexposed children were followed up for an average of 12.3 years (SD 7.3). Results: In our sample 94 943 children were exposed to bereavement, and 6110 cases of type 1 diabetes were identified. Bereavement was associated with an increased rate of type 1 diabetes when exposure onset began after 11 years of age (adjusted IRR 1.28, 95% confidence interval 1.08, 1.51). Conclusion: We found some evidence to indicate an increase in the rate of type 1 diabetes among children exposed to bereavement when exposure occurred after 11 years of age.
    No preview · Article · Oct 2015 · Paediatric and Perinatal Epidemiology
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    ABSTRACT: To investigate the impact of prenatal antidepressant exposure on behavioural problems in children at 7 years of age. Nationwide population-based study. Danish National Birth Cohort. A cohort of 49 178 pregnant women recruited between 1996 and 2002. Data obtained from computer-assisted telephone interviews twice during pregnancy were used to identify children born to: (i) depressed women who took antidepressants during pregnancy (n = 210); (ii) depressed women who did not take any antidepressants during pregnancy (n = 231); and (iii) healthy women who were not depressed (n = 48 737). Childhood behavioural problems at 7 years of age were examined using the validated Danish parent-report version of the Strengths and Difficulties Questionnaire (SDQ). SDQ scores. No associations were observed between prenatal antidepressant exposure and abnormal SDQ scores for overall problem behaviour (adjusted relative risk, aRR 1.00; 95% confidence interval, 95% CI 0.49–2.05), hyperactivity/inattention (aRR 0.99; 95% CI 0.56–1.75), or peer problems (aRR 1.04; 95% CI 0.57–1.91). Although prenatal antidepressant exposure appeared to be associated with abnormal SDQ scores on the subscales of emotional symptoms (aRR 1.68; 95% CI 1.18–2.38) and conduct problems (aRR 1.58; 95% CI 1.03–2.42), these associations were significantly attenuated following adjustment for antenatal mood status (aRR 1.20; 95% CI 0.85–1.70 and aRR 1.19; 95% CI 0.77 1.83, respectively). Untreated prenatal depression was associated with an increased risk of all behavioural outcomes evaluated, compared with unexposed children, with significant attenuation following adjustment for antenatal mood status. The results of this study suggest that independent of maternal illness, prenatal antidepressant exposure is not associated with an increased risk of behavioural problems in children at 7 years of age. Prenatal antidepressant exposure is not associated with an increased risk of child behavioural problems.
    No preview · Article · Sep 2015 · BJOG An International Journal of Obstetrics & Gynaecology
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    ABSTRACT: Background: The prevalence of citizens diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) has risen dramatically over the past decades in many countries, however, with large variations. Countries such as Denmark with centrally organized well fare systems, free access to health services and individual tracking based on unique personal identification may in particular contribute to our understanding of the reasons for this increase. Based on Danish registers we aimed to examine the geographical patterns of the distribution of ADHD diagnosis and medication use and explore the association with access to diagnostic services, diagnostic culture, neighbourhood socioeconomic status and municipal spending on health care for children. Methods: We combined information on registered diagnosis of ICD-10 Hyperkinetic Disorder and ADHD medication use in a Danish register-based cohort of children born between 1990 and 2000. We mapped incidence proportions of diagnoses and medication use within the 98 Danish Municipalities. Global and local clustering of ADHD was identified using spatial analysis. Information on contextual factors in the municipalities was obtained from national registers. The associations between the incidence of ADHD and contextual factors were analysed using Bayesian spatial regression models. Results: We found a considerable variation in the incidence of ADHD across the municipalities. Significant clustering of both high and low incidence of ADHD was identified and mapped using the local Moran's I. Clustering of low incidence of diagnosis and medication use was observed in less populated areas with limited diagnostic resources and in contrast clustering of high incidence in densely populated areas and greater diagnostic resources. When considering the spatial autocorrelation between neighbouring municipalities, no significant associations were found between ADHD and access to diagnostic services, different diagnostic culture, socioeconomic status at municipality level or the municipal spending on health care for children. Conclusions: A large geographical variation of ADHD in the municipalities was observed despite tax-financed and free access to healthcare. Although not statistically significant, results indicate that accessibility to diagnostic resources might explain some of the variation in ADHD incidence. In contrast to US studies the observed variation was not statistically associated to contextual factors in terms of SES, municipal spending on health care for children or differences in diagnostic practices.
    Full-text · Article · Aug 2015 · International Journal of Health Geographics
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    ABSTRACT: Background We investigated whether bereavement of a close family member – a source of severe psychological stress exposure – the year before pregnancy is associated with gestational diabetes mellitus (GDM).Methods We studied pregnant women with livebirths in Denmark during 1994–2008 and with births in Sweden during 1987–2006 (n = 2 569 446). We obtained data on death of women's parents, siblings, and older children, and on demographic and health- and pregnancy-related factors through linkage between nationwide registers.ResultsIn multivariable models, death of a close relative the year before pregnancy was associated with a 14% increased odds of GDM [95% confidence intervals (CIs) 1.03, 1.26]. The odds ratios corresponding to the loss of a child, parent, and sibling were 1.51 (95% CI: 1.17, 1.95), 1.12 (95% CI: 1.00, 1.25), and 0.68 (95% CI: 0.40, 1.25), respectively. Deaths due to cardiovascular diseases or diabetes were more closely related to the risk of GDM than other types of deaths. We found no association between unnatural deaths and the risk of GDM.Conclusions Death of a close relative the year before pregnancy was associated with a modestly increased GDM risk. Our findings according to the relative's cause of death suggest that differences in screening for GDM among exposure groups and residual confounding by familial factors related to metabolic and cardiovascular diseases may have contributed to this association. If there is a causal stress effect on GDM in this predominantly Nordic population, it is most likely small.
    No preview · Article · Jul 2015 · Paediatric and Perinatal Epidemiology
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    ABSTRACT: Background: A previous randomized trial demonstrated an association between coffee intake and birth weight in smokers only. This could be a chance finding or because smoking interferes with caffeine metabolism. This study assessed the association between coffee intake during pregnancy and birth weight and whether it was modified by the mothers' smoking habits. Methods: In the Danish National Birth Cohort, coffee intake and smoking during pregnancy were recorded prospectively in 89,539 pregnancies that ended with live born singletons. Information on birth weight was obtained from the Danish Medical Birth Register. For a total of 71,000 pregnancies, complete information was available on coffee intake and all covariates for the second trimester. Results: Second-trimester coffee intake was associated with reduced birth weight in a dose-response pattern for non-smokers and smokers (9 g/cup/day). Compared to non-coffee drinkers, intake of eight or more cups of coffee per day was associated with an adjusted birth weight difference of −65 g [95% confidence interval (CI) −92 to −39] for non-smokers and −79 g [95% CI −124 to −34] for women smoking more than 10 cigarettes per day. Women drinking eight or more cups of coffee per day had a higher risk of giving birth to a child small for gestational age (adjusted odds ratio=1.51 [95% CI 1.21-1.88]). These associations were found among both smokers and non-smokers. Conclusion: Coffee intake during pregnancy is associated with reduced birth weight in smokers as well as non-smokers, and may increase the risk of giving birth to small for gestational age children, but the association is small for intakes of coffee of less than eight cups per day.
    No preview · Article · Apr 2015
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    ABSTRACT: Early parental separation may be a stress factor causing a long-term alteration in the hypothalamic-pituitary-adrenal-axis activity possibly impacting on the susceptibility to develop overweight and obesity in offspring. We aimed to examine the body mass index (BMI) and the risk of overweight and obesity in children whose parents lived separately before the child was born. A follow-up study was conducted using data from the Aarhus Birth Cohort in Denmark and included 2876 children with measurements of height and weight at 9-11-years-of-age, and self-reported information on parental cohabitation status at child birth and at 9-11-years-of-age. Quantile regression was used to estimate the difference in median BMI between children whose parents lived separately (n = 124) or together (n = 2752) before the birth. We used multiple logistic regression to calculate odds ratio (OR) for overweight and obesity, adjusted for gender, parity, breast feeding status, and maternal pre-pregnancy BMI, weight gain during pregnancy, age and educational level at child birth; with and without possible intermediate factors birth weight and maternal smoking during pregnancy. Due to a limited number of obese children, OR for obesity was adjusted for the a priori confounder maternal pre-pregnancy BMI only. The difference in median BMI was 0.54 kg/m2 (95% confidence intervals (CI): 0.10; 0.98) between children whose parents lived separately before birth and children whose parents lived together. The risk of overweight and obesity was statistically significantly increased in children whose parents lived separately before the birth of the child; OR 2.29 (95% CI: 1.18; 4.45) and OR 2.81 (95% CI: 1.05; 7.51), respectively. Additional, adjustment for possible intermediate factors did not substantially change the estimates. Parental separation before child birth was associated with higher BMI, and increased risk of overweight and obesity in 9-11-year-old children; this may suggest a fetal programming effect or unmeasured difference in psychosocial factors between separated and non-separated parents.
    Full-text · Article · Mar 2015 · PLoS ONE
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    ABSTRACT: Oxytocin for labor augmentation is widely used in obstetric care in Western countries. Two recent, smaller studies found opposing results regarding the association between prenatal exposure to oxytocin for labor augmentation and attention-deficit/hyperactivity disorder (ADHD). In Denmark, oxytocin is the medication used for nearly all medical augmentations of labor, and we examined the association between medical augmentation of labor and ADHD in a large cohort study based on national register data. All singletons born after spontaneous onset of labor in Denmark between 2000 and 2008 (N = 546 146) were included in the study. Data from the Danish Medical Birth Registry on medical augmentation of labor (yes/no) were used to identify exposed children. ADHD was defined based on the diagnostic codes of International Classification of Diseases, 10th Revision, for hyperkinetic disorder and information on dispensed ADHD medication. A multivariate proportional hazards regression model was used to test the association. Among 546 146 deliveries, 26% included medical augmentation of labor, and 0.9% of the children were identified as having ADHD (n = 4617). We found no association between augmentation of labor and ADHD in the offspring (hazard ratio: 1.05 [95% confidence interval: 0.98-1.13]). Our study does not support an association between medical augmentation of labor and ADHD in the child. Copyright © 2015 by the American Academy of Pediatrics.
    No preview · Article · Feb 2015 · Pediatrics
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    ABSTRACT: In animal studies, perfluorinated alkyl substances affect growth and neuro-behavioural outcomes. Human epidemiological studies are sparse. The aim was to investigate the association between pregnancy serum concentrations of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) and offspring behaviour and motor development at 5-9 years of age. Maternal sera from the INUENDO cohort (2002-2004) comprising 1,106 mother-child pairs from Greenland, Kharkiv (Ukraine) and Warsaw (Poland) were analysed for PFOS and PFOA, using liquid-chromatography-tandem-mass-spectrometry. Exposures were grouped into country specific as well as pooled tertiles as well as being used as continuous variables for statistical analyses. Child motor development and behaviour at follow-up (2010-2012) were measured by the Developmental Coordination Disorder Questionnaire 2007 (DCDQ) and Strength and Difficulties Questionnaire (SDQ), respectively. Exposure-outcome associations were analysed by multiple logistic and linear regression analyses. In the pooled analysis, odds ratio (OR) (95% confidence interval (CI)) for hyperactivity was 3.1 (1.3, 7.2) comparing children prenatally exposed to the highest PFOA tertile with those exposed to the lowest PFOA tertile. Comparing children in the highest PFOS tertile with those in the lowest PFOS tertile showed elevated but statistically non-significant OR of hyperactivity (OR (95% CI) 1.7 (0.9, 3.2)). In Greenland, elevated PFOS was associated with higher SDQ-total scores indicating more behavioural problems (beta (95% CI) =1.0 (0.1, 2.0)) and elevated PFOA was associated with higher hyperactivity sub-scale scores indicating more hyperactive behaviour (beta (95% CI) = 0.5 (0.1, 0.9)). Prenatal PFOS and PFOA exposures were not associated with motor difficulties. Prenatal exposure to PFOS and PFOA may have a small to moderate effect on children's neuro-behavioural development, specifically in terms of hyperactive behaviour. The associations were strongest in Greenland where exposure contrast is largest.
    Full-text · Article · Jan 2015 · Environmental Health
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    ABSTRACT: Objectives Maternal body mass index (BMI), birth weight, and preschool BMI may help identify children at high risk of overweight as they are (1) similarly linked to adolescent overweight at different stages of the obesity epidemic, (2) linked to adult obesity and metabolic alterations, and (3) easily obtainable in health examinations in young children. The aim was to develop early childhood prediction models of adolescent overweight, adult overweight, and adult obesity.Methods Prediction models at various ages in the Northern Finland Birth Cohort born in 1966 (NFBC1966) were developed. Internal validation was tested using a bootstrap design, and external validation was tested for the model predicting adolescent overweight using the Northern Finland Birth Cohort born in 1986 (NFBC1986).ResultsA prediction model developed in the NFBC1966 to predict adolescent overweight, applied to the NFBC1986, and aimed at labelling 10% as “at risk” on the basis of anthropometric information collected until 5 years of age showed that half of those at risk in fact did become overweight. This group constituted one-third of all who became overweight.Conclusions Our prediction model identified a subgroup of children at very high risk of becoming overweight, which may be valuable in public health settings dealing with obesity prevention.
    No preview · Article · Jan 2015 · Obesity
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    ABSTRACT: Comparative data of parental separation and childhood overweight has not been available before across the Nordic countries. The aim of this study was to examine the within-country prevalence and association between parental cohabitation and overweight in Nordic children. A cross-sectional survey of 2-17-year-old children was conducted in 2011, titled: "NordChild". A random sample of 3,200 parents in each of the Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden were invited to participate in the study with parents of 6,609 children accepting to give answers about their children's health and welfare including information on height and weight of each child and parental cohabitation (response rate 41.5%). The group differences in prevalence and adjusted odds ratio (OR) for overweight, with corresponding 95% confidence intervals (CI) were performed in children whose parents lived separately. Additionally, a missing data analysis was performed to determine whether the adjusted estimates might result from confounding or selection bias. A significant difference was observed in Iceland between children whose parents live separately compared to those who live with both parents (difference: 9.4%, 95% CI: 2.8; 15.9) but no such difference was observed in Denmark, Finland, Norway and Sweden. No significant odds of overweight were observed in children whose parents lived separately compared to children in normal weight at the time of study; Denmark: OR 1.03 (95% CI: 0.42; 2.53), Finland: OR 1.27 (95% CI: 0.74; 2.20), Iceland: OR 1.50 (95% CI: 0.79; 2.84), Norway: OR 1.46 (95% CI: 0.81; 2.62), and Sweden: 1.07 (95% CI: 0.61; 1.86). The missing data analysis indicated that the findings in Norway, Finland and Iceland were partly observed due to selection effects, whereas the adjustment in Denmark was due to confounding. The crude OR for overweight was higher in the 2-9-year-old group than in the 10-17-year-old group whose parents lived separately in Iceland, Norway and Sweden. No association between parental cohabitation and overweight in Nordic children was found. Our finding of greater prevalence of overweight in Icelandic children whose parents live separately may be an indication that the welfare system in Iceland is separating from the other Nordic countries.
    Full-text · Article · Nov 2014 · BMC Public Health
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    ABSTRACT: Animal and human studies suggest that programing of the hypothalamic-pituitary-adrenal (HPA) axis may be involved in the development of obesity, but human studies of biological indicators of HPA axis activity are lacking. We studied the association between levels of the stress hormone cortisol during pregnancy and overweight offspring during childhood into adolescence. Salivary samples from 655 Danish pregnant women with singleton pregnancies (1989-1991) were collected once in the morning and once in the evening in their second and third trimester. We followed the offspring from two to 16 years of age with at least one measurement of height and weight, and classified their body mass index into overweight and normal weight. The adjusted relative difference in median salivary cortisol (with 95% confidence interval (CI)) during pregnancy (the four samples), in second and third trimester (morning and evening samples) between overweight and normal weight offspring was estimated. Furthermore, the adjusted median ratio between morning and evening maternal salivary cortisol level was estimated for normal weight and overweight children. All the analyses were stratified into the equal age groups: 2-6, 7-11, and 12-16 years. We found non-significant higher maternal cortisol levels during pregnancy in offspring that were overweight at the age of 2-6, 7-11 and 12-16 years than in normal weight peers; adjusted relative difference in median salivary cortisol 11% (95% CI: -2; 25), 6% (95% CI: -7; 20), and 9% (95% CI: -4; 24), respectively. A statistically significantly higher level of maternal cortisol was found in the second trimester in 2-6-year-old and 12-16-year-old overweight offspring; relative difference 19% (95% CI: 3; 37), and 20% (95% CI: 3; 41), respectively. The median ratio between morning and evening maternal salivary cortisol level was similar for overweight and normal weight children; e.g. at age 2-6 years in third trimester 4.31 (95% CI: 4.05; 4.60)nmol/l and 4.28 (95% CI: 3.60; 5.09)nmol/l, respectively (P=0.93). Our findings suggest a relatively consistent association between pregnancy cortisol levels and overweight offspring, especially in the second trimester. Copyright © 2014 Elsevier Ltd. All rights reserved.
    Full-text · Article · Nov 2014 · Psychoneuroendocrinology

  • No preview · Article · Sep 2014 · Reproductive Toxicology
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    ABSTRACT: Objectives: Few epidemiological studies have studied maternal stress exposure during pregnancy and odds of asthma and atopic dermatitis (AD) among offspring, and none have extended the focus to psychosocial job strain. The aim of this study was to assess the association between maternal job strain during pregnancy and asthma as well as AD among 7-year-old children. Methods: The study is based on the Danish National Birth Cohort and includes prospective data from 32 104 pregnancies. Job strain was assessed early in pregnancy by use of two questions on demands and control. We categorized participants into four job strain categories: low strain (low demands, high control), active (high demands, high control), passive (low demands, low control), and high strain (high demands, low control). Information on asthma and AD until age seven was collected using maternal self-report. Multinomial logistic regression models were used to estimate odds ratios (OR) with 95% confidence intervals (95% CI) adjusted for several covariates. Results: Maternal exposure to self-reported high strain during pregnancy was associated with 15% higher odds of atopic dermatitis among 7-year-old children (OR adj1.15, 95% CI 1.02-1.31). Furthermore, an association between the active jobs and asthma among 7-year-old children was found (OR adj1.13, 95% CI 1.03-1.24). Conclusion: Maternal exposure to high strain and active jobs during pregnancy was associated with asthma and atopic dermatitis among 7-year-old children.
    No preview · Article · Aug 2014 · Scandinavian Journal of Work, Environment & Health
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    ABSTRACT: Background: Prenatal maternal smoking has been associated with attention-deficit/hyperactivity disorder (ADHD) in children, but the causal nature of this association is still under scrutiny. We examined the association with maternal smoking and nicotine replacement use during pregnancy, using association with paternal smoking as a marker of potential genetic or social confounding. Methods: We included 84 803 singletons who participated in the Danish National Birth Cohort. Information on parental smoking was reported by the mothers during pregnancy. Children with ADHD were identified from the Danish Psychiatric Central Register, the Danish National Patient Register, and the Register of Medicinal Product Statistics by the International Classification of Diseases, 10th Revision diagnosis or medication. We also used hyperactivity/inattention score of the parent-reported Strengths and Difficulties Questionnaire, included in the 7-year follow-up of the National Birth Cohort. Results: Maternal and paternal smoking during pregnancy were associated with an elevated risk of ADHD defined by hospital diagnosis, medication, and hyperactivity/inattention score, but the association was stronger for maternal smoking than for paternal smoking. Compared with children born to nonsmoking mothers and smoking fathers, children born of smoking mothers and nonsmoking fathers had a higher risk of ADHD (adjusted hazard ratio = 1.26; 95% confidence interval, 1.03 to 1.53). We also saw a higher risk of ADHD in children of mothers who used nicotine replacement during pregnancy. Conclusions: Our findings indicate that the association between prenatal maternal smoking and ADHD may overestimate a causal link, but nicotine exposure or related factors may still play a causal role.
    Full-text · Article · Jul 2014 · PEDIATRICS
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    ABSTRACT: Background: Bereavement by spousal death and child death in adulthood has been shown to lead to an increased risk of mortality. Maternal death in infancy or parental death in early childhood may have an impact on mortality but evidence has been limited to short-term or selected causes of death. Little is known about long-term or cause-specific mortality after parental death in childhood. Methods and findings: This cohort study included all persons born in Denmark from 1968 to 2008 (n = 2,789,807) and in Sweden from 1973 to 2006 (n = 3,380,301), and a random sample of 89.3% of all born in Finland from 1987 to 2007 (n = 1,131,905). A total of 189,094 persons were included in the exposed cohort when they lost a parent before 18 years old. Log-linear Poisson regression was used to estimate mortality rate ratio (MRR). Parental death was associated with a 50% increased all-cause mortality (MRR = 1.50, 95% CI 1.43-1.58). The risks were increased for most specific cause groups and the highest MRRs were observed when the cause of child death and the cause of parental death were in the same category. Parental unnatural death was associated with a higher mortality risk (MRR = 1.84, 95% CI 1.71-2.00) than parental natural death (MRR = 1.33, 95% CI 1.24-1.41). The magnitude of the associations varied according to type of death and age at bereavement over different follow-up periods. The main limitation of the study is the lack of data on post-bereavement information on the quality of the parent-child relationship, lifestyles, and common physical environment. Conclusions: Parental death in childhood or adolescence is associated with increased all-cause mortality into early adulthood. Since an increased mortality reflects both genetic susceptibility and long-term impacts of parental death on health and social well-being, our findings have implications in clinical responses and public health strategies. Please see later in the article for the Editors' Summary.
    Full-text · Article · Jul 2014 · PLoS Medicine
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    ABSTRACT: Perinatal stress may programme overweight and obesity. We examined whether maternal pre- and post-natal bereavement was associated with overweight and obesity in young men. A cohort study was conducted including 119,908 men born from 1976 to 1993 and examined for military service between 2006 and 2011. Among them, 4,813 conscripts were born to mothers bereaved by death of a close relative from 12 months preconception to birth of the child (exposed group). Median body mass index (BMI) and prevalence of overweight and obesity were estimated. Odds ratio of overweight (BMI≥25 kg/m2) and obesity (BMI≥30 kg/m2) were estimated by logistic regression analysis adjusted for maternal educational level. Median BMI was similar in the exposed and the unexposed group but the prevalence of overweight (33.3% versus 30.4%, p = 0.02) and obesity (9.8% versus 8.5%, p = 0.06) was higher in the exposed group. Conscripts exposed 6 to 0 months before conception and during pregnancy had a higher risk of overweight (odds ratio 1.15, 95% confidence interval (CI): 1.03; 1.27 and odds ratio 1.13, 95% CI: 1.03; 1.25, respectively). Conscripts born to mothers who experienced death of the child's biological father before child birth had a two-fold risk of obesity (odds ratio 2.00, 95% CI: 0.93; 4.31). There was no elevated risk in those who experienced maternal bereavement postnatally. Maternal bereavement during the prenatal period was associated with increased risk of overweight or obesity in a group of young male conscripts, and this may possibly be reflected to severe stress exposure early in life. However, not all associations were clear, and further studies are warranted.
    Full-text · Article · May 2014 · PLoS ONE

Publication Stats

3k Citations
477.47 Total Impact Points

Institutions

  • 2003-2015
    • Aarhus University
      • • Department of Public Health
      • • Department of Clinical Epidemiology
      • • Department of Epidemiology and Social Medicine
      Aarhus, Central Jutland, Denmark
  • 1998-2011
    • Aarhus University Hospital
      • Department of Obstetrics and Gynaecology
      Aarhus, Central Jutland, Denmark
  • 2009
    • University of Southern Denmark
      Odense, South Denmark, Denmark
  • 2007
    • County of Los Angeles Public Health
      Los Ángeles, California, United States