Abstract: Substance use disorder (SUD) is associated with major socioeconomic consequences but its etiology is only partly known. The disease predisposition may be established early in life and prenatal stress may play a role. We aimed to examine whether prenatal maternal bereavement, as the indicator of prenatal stress, was associated with an increased risk of SUD in offspring.
Abstract: Increasing evidence suggests that maternal stress during pregnancy may influence pregnancy outcomes. In a nationwide Swedish study including almost 3 million births taking place during 1973-2006, we investigated whether maternal bereavement during pregnancy is associated with stillbirth risk. Through individual record linkage between several population-based registers, we obtained information on demographic, health-related, and pregnancy-related factors and deaths of mothers' first-degree relatives. There were 11,071 stillbirths (3.8 per 1,000 births) in the cohort. After adjustment for potential confounders, infants of mothers who had lost any first-degree relative the year before or during pregnancy had an 18% higher risk of stillbirth than unexposed offspring (95% confidence interval (CI): 1.06, 1.31). Corresponding hazard ratios were 1.67 (95% CI: 1.18, 2.36) for maternal loss of an older child, 2.06 (95% CI: 1.44, 2.94) for loss of a sibling, and 1.07 (95% CI: 0.95, 1.21) for loss of a parent. The relationship between maternal bereavement and stillbirth did not vary by time of death or by whether the relative's death was expected or unexpected. Death of a close relative is one of the most severe sources of stress, and future studies need to investigate whether less severe but more common stressors also increase stillbirth risk.
Abstract: The aim of this study was to examine the factor structure of the Strengths and Difficulties Questionnaire (SDQ) using a Structural Confirmatory Factor Analytic approach. The Danish translation of the SDQ was distributed to 71,840 parents and teachers of 5-7 and 10-12-year-old boys and girls from four large scale cohorts. Three theoretical models were examined: 1. a model with five first order factors (i.e., hyperactivity/inattention, conduct, emotional, peer problems and prosocial), 2. a model adding two internalising and externalising second order factors to model 1, and 3. a model adding a total difficulties second order factor to model 1. Model fits were evaluated, multi-group analyses were carried out and average variance extracted (AVE) and composite reliability (CR) estimates were examined. In this general population sample, low risk sample models 1 and 2 showed similar good overall fits. Best model fits were found when two positively worded items were allowed to cross load with the prosocial scale, and cross loadings were allowed for among three sets of indicators. The analyses also revealed that model fits were slightly better for teachers than for parents and better for older children than for younger children. No convincing differences were found between boys and girls. Factor loadings were acceptable for all groups, especially for older children rated by teachers. Some emotional, peer, conduct and prosocial subscale problems were revealed for younger children rated by parents. The analyses revealed more internal consistency for older children rated by teachers than for younger children rated by parents. It is recommended that model 1 comprising five first order factors, or alternatively model 2 with additionally two internalising/externalising second order factors, should be used when employing the SDQ in low risk epidemiological samples.
Abstract: A number of studies examined the effects of prenatal stress on birth outcomes with diverging and inconclusive results. We aimed to examine if working with high job strain during pregnancy measured in week 16 was associated with risk of giving birth to a child born preterm or small/large for gestational age (SGA/LGA), and second, if social support affected any associations.
Abstract: It has been suggested that maternal emotional stress during cardiogenesis may be a risk factor for congenital heart defects (CHD). We examined this association using bereavement around the time of conception as an indicator of maternal exposure to stress in a large registry-based study.
Abstract: Maternal stress during pregnancy is associated with a modestly increased risk of fetal growth restriction and pre-eclampsia. Since placental abruption shares similar pathophysiological mechanisms and risk factors with fetal growth restriction and pre-eclampsia, we hypothesized that maternal stress may be implicated in abruption risk. We investigated the association between maternal bereavement during pregnancy and placental abruption.
Abstract: The role of stress in the pathogenesis of preeclampsia has only been investigated in a few studies, and the findings are not conclusive. We analyzed whether maternal bereavement shortly before or during pregnancy is associated with an increased risk of preeclampsia. We conducted a cohort study of singleton births in Denmark during 1978-2008 and in Sweden during 1973-2006 (n=4 122 490) by linking national population-based registers. Mothers were considered exposed to bereavement if they lost a parent, a sibling, a partner, or a child the year before or during pregnancy (n=124 553). The risk of preeclampsia was slightly increased for women who lost a close relative during the 6 months before conception (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.06-1.23) or during the first trimester of pregnancy (OR, 1.15; 95% CI, 1.03-1.29). Exposure during these periods tended to be more closely related to early preeclampsia (delivery before 34 weeks of gestation; OR, 1.37; 95% CI, 1.12-1.67) than to late preeclampsia (OR, 1.13; 95% CI, 1.06-1.20). The strongest association was observed between loss of a child and early preeclampsia when the exposure window was from 6 months before pregnancy until start of second trimester (OR, 4.03; 95% CI, 2.46-6.61). Our results related to timing of exposure suggest that severe stress may influence early placentation. However, the public health implications of our findings are limited in populations with a low prevalence of severe stress exposures.
Abstract: Survey response rates have been declining over the past decade. The more widespread use of the Internet and Web-based technologies among potential health survey participants suggests that Web-based questionnaires may be an alternative to paper questionnaires in future epidemiological studies.
Abstract: The etiology of autism spectrum disorders (ASD) is for the majority of cases unknown and more studies of risk factors are needed. Geographic variation in ASD occurrence has been observed, and urban residence has been suggested to serve as a proxy for etiologic and identification factors in ASD. We examined the association between urbanicity level and ASD at birth and during childhood. The study used a Danish register-based cohort of more than 800,000 children of which nearly 4,000 children were diagnosed with ASD. We found a dose-response association with greater level of urbanicity and risk of ASD. This association was found for residence at birth as well as residence during childhood. Further, we found an increased risk of ASD in children who moved to a higher level of urbanicity after birth. Also, earlier age of ASD diagnosis in urban areas was observed. While we could not directly examine the specific reasons behind these associations, our results demonstrating particularly strong associations between ASD diagnosis and post-birth migration suggest the influence of identification-related factors such as access to services might have a substantive role on the ASD differentials we observed.
Abstract: The Strength and Difficulties Questionnaire (SDQ) is a brief behavioural five factor instrument developed to assess emotional and behavioural problems in children and adolescents. The aim of the current study was to evaluate the psychometric properties for parent and teacher ratings in the Danish version of SDQ for different age groups of boys and girls.
Abstract: We sought to study the possible association between parental age and autism spectrum disorder (ASD) by using both a cohort design and a sibling design.
Abstract: It has been hypothesized that prenatal exposure to testosterone may be associated with traits of attention-deficit/hyperactivity disorder (ADHD) or autism spectrum disorder (ASD). We conducted a population-based study of dizygotic female twins to elucidate this hypothesis, assuming that the sex of the co-twin influences the level of prenatal exposure to testosterone. We invited parents of 24,552 3- to 15-year-old twins to answer questionnaires on traits of ADHD and ASD. We analysed the data using a proportional odds model with sex of the co-twin as an instrumental variable for prenatal exposure to testosterone of female twins. We received responses for 6,339 girls from dizygotic twin pairs. Odds ratios for male versus female co-twin were 0.71 (95Â % confidence interval 0.61-0.81) for ADHD traits and 0.74 (0.66-0.83) for ASD traits, indicating that a twin brother reduces traits of ADHD and ASD in females. In conclusion, we found that female twins with a twin brother scored significantly lower in parent-reported traits of ADHD and ASD than those with a twin sister. The reason for this may be parental reporting bias, or confounding by unmeasured variables, or a causal effect of an intrauterine environment modified by the sex of the co-twin in the opposite direction of what we expected.
Abstract: To estimate the prevalence of the ADHD phenotype based on parent and teacher reports in a general population sample of 7- to 9-year-old Norwegian children and evaluate the effect of parent attrition, gender and informant on the prevalence estimate.
Abstract: Potential health effects of cell phone use in children have not been adequately examined. As children are using cell phones at earlier ages, research among this group has been identified as the highest priority by both national and international organisations. The authors previously reported results from the Danish National Birth Cohort (DNBC), which looked at prenatal and postnatal exposure to cell phone use and behavioural problems at age 7 years. Exposure to cell phones prenatally, and to a lesser degree postnatally, was associated with more behavioural difficulties. The original analysis included nearly 13 000 children who reached age 7 years by November 2006.
Abstract: To examine the prevalence, clinical characteristics and course of children with tics identified in a community sample. This was a three-stage study. At the age of 9 to 11, parents of 8,244 children born at Aarhus University Hospital Skejby between January 1990 and April 1992 were invited to complete a screening questionnaire about tics. One year later participating parents completed the Strengths and Difficulties Questionnaire (SDQ). From December 2004 to June 2005, when the cohort was 13-15 years of age, parents of the children who screened positive for tics were interviewed in detail about tic disorders. The prevalence of Tourette Syndrome (TS) was 0.6 and 0.6% of chronic motor tics (CMT). Approximately one-third of those with a chronic tic disorder [CTD (TS and CMT)] reported remission of tics by age 13-15. On the parent-rated SDQ children with a CTD were five times more likely (OR = 5.0, 95% CI = 2.6-9.2) to fall into the clinical range of hyperactivity, twice as likely (OR = 2.2, 95% CI = 2.1-7.5) to exhibit disruptive and defiant behavior and over four times more likely to have emotional difficulties (OR = 4.7, 95% CI = 2.5-8.6) compared to children without tic disorders. Children with hyperactivity and CTD were more impaired than subjects with CTD only. Children with CTD and hyperactivity show greater symptom severity across several domains of behavior and overall impairment. In the absence of hyperactivity, children with CTD are at increased risk for emotional difficulties, but not disruptive behavior problems.
Abstract: The rise in the occurrence of childhood obesity during the last decades in many populations indicates an important role of environmental exposures, which may operate very early in life. We aimed to examine the association between bereavement during the first 6 years of life, as a stress indicator, and subsequent risk of overweight in school-aged children.
Abstract: Prenatal stress may increase the susceptibility to childhood cancer by affecting immune responses and hormonal balance. We examined whether antenatal stress following maternal bereavement increased the risk of childhood cancer.
Abstract: To evaluate general practitioners' (GPs') assessment of potential overweight among children attending the five-year preventive child health examination (PCHE) by comparing their assessment of the children's weight-for-stature with overweight defined by body mass index (BMI) according to paediatric standard definitions.
Abstract: The etiology of type-2 diabetes is only partly known, and a possible role of prenatal stress in programming offspring for insulin resistance has been suggested by animal models. Previously, we found an association between prenatal stress and type-1 diabetes. Here we examine the association between prenatal exposure to maternal bereavement during preconception and pregnancy and development of type-2 diabetes in the off-spring.
Abstract: The aetiology of childhood cancer remains largely unknown but recent research indicates that uterine environment plays an important role. We aimed to examine the association between the Apgar score at 5 min after birth and the risk of childhood cancer.
Abstract: Behavioural patterns in children of infertile couples may be influenced by both the underlying causes of infertility and stress in the couples. Treatment procedures, such as culture media and manipulation of gametes and embryos, may also result in developmental problems. We examined behavioural problems in children as a function of infertility and infertility treatment, using data from three population-based birth cohorts in Denmark (Aalborg-Odense Birth Cohort, Aarhus Birth Cohort and Danish National Birth Cohort). Information on time to pregnancy and infertility treatment was collected during pregnancy. Children aged between 7 and 21 years were assessed using the Strengths and Difficulties Questionnaire (SDQ). The SDQ was completed by mothers in all cohorts and, in addition, by teachers in the Aarhus cohort and by children themselves in the Aalborg-Odense cohort. Children born after a time to pregnancy of >12 months and no infertility treatment had a behavioural pattern similar to children of fertile parents. Teachers reported a higher total difficulties score for children born after infertility treatment, but no significant differences were seen on any subscales of the teachers' report, and neither the mothers nor the children reported any differences on the total difficulties score and the prosocial behaviour score. Our results are thus overall reassuring regarding behavioural problems in children born to infertile couples, regardless of infertility treatment.
Abstract: A number of studies have examined the effects of prenatal exposure to stress on birth outcomes but few have specifically focused on psychosocial job strain. In the present protocol, we aim to examine if work characterised by high demands and low control, during pregnancy, is associated with the risk of giving birth to a child born preterm or small for gestational age.
Abstract: Studies have consistently shown that pregnancy smoking is associated with twice the risk of hyperactivity/inattention problems in the offspring. An association of this magnitude may indicate behavioural difficulties as one of the most important health effects related to smoking during pregnancy. However, social and genetic confounders may fully or partially account for these findings.
Abstract: The strengths and difficulties questionnaire (SDQ) is a broad-band child mental health instrument, which has been reported to be a good screener for the ADHD phenotype. Questionnaires containing the SDQ and the 18 SNAP-IV items corresponding to the DSM-IV ADHD symptoms were completed by parents and teachers for 66% (NÂ =Â 6,233) of all 7- to 9-year-olds in the city of Bergen, Norway, 2002. Screening properties of the five-item SDQ hyperactivity-inattention subscale for the DSM-IV ADHD phenotype were examined. Using the DSM-IV ADHD phenotype based on both informants as the gold standard (5.2% of the sample), the receiver operating characteristics (ROC) analyses demonstrated an area under the curve of 0.91 (95% CI: 0.90-0.92) for parent and 0.95 (95% CI: 0.94-0.95) for teacher SDQ hyperactivity-inattention subscale ratings. The SDQ hyperactivity-inattention predictive algorithm identified 74% of those with the ADHD combined subtype as possible or probable cases, but only 22% of those with the inattentive subtype. The 5-item long SDQ hyperactivity-inattention subscale is a shorter substitute for the 18-item ADHD symptom list. The SDQ predictive algorithm had an acceptable sensitivity for the ADHD combined subtype, but low sensitivity for the ADHD inattentive and the ADHD hyperactive subtypes.
Abstract: Severe prenatal stress exposure has been found to increase the risk of neuropsychiatric conditions like schizophrenia. We examined the risk of attention-deficit/hyperactivity disorder (ADHD) in the offspring following prenatal maternal bereavement, as a potential source of stress exposure. We conducted a nationwide population-based cohort study including all 1,015,912 singletons born in Denmark from 1987 to 2001. A total of 29,094 children were born to women who lost a close relative during pregnancy or up to 1 year before pregnancy. These children were included in the exposed cohort and other children were in the unexposed cohort. We used Cox regression to estimate hazard ratios for ADHD, defined as the first-time ADHD hospitalization or first-time ADHD medication after 3 years of age. Boys born to mothers who were bereaved by unexpected death of a child or a spouse, had a 72% increased risk of ADHD [hazard ratio (HR) 1.72, 95% confidence interval (CI) 1.09-2.73]. Boys born to mothers who lost a child or a spouse during 0-6 months before pregnancy and during pregnancy had a HR of 1.47 (95% CI 1.00-2.16) and 2.10 (95% CI 1.16-3.80), respectively. Our findings suggest that prenatal maternal exposure to severe stress may increase the risk of ADHD in the offspring.
Abstract: It has previously been reported that children born after infertility treatment had a slight delay in early motor milestones. In this study, we examined whether children of infertile couples with or without infertility treatment had a higher risk of developmental coordination disorder (DCD).
Abstract: Children born after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) have been reported to have a higher risk of cerebral palsy (CP), perhaps due to the higher frequency of preterm birth, multiple births or vanishing embryo in the pregnancies. However, it has been suggested that the underlying infertility may be part of the pathway. In this study, we examined whether untreated subfecundity (measured by time to pregnancy) or infertility treatment was associated with an increased risk of CP in the offspring.
Abstract: To assess the risk of developing Type-1 diabetes among children who were exposed to maternal bereavement during the prenatal or 1-year preconception period.
Abstract: The aim was to study the association between preschool behavioural problems and emotional symptoms in 10- to 12-year-old children. The study was based on the Aarhus Birth cohort, Denmark, and included 1,336 children. Based on the parent-administered preschool behaviour questionnaire (PBQ), we identified three not mutually exclusive preschool behavioural categories: anxious-fearful (n = 146), hyperactive-distractible (n = 98), and hostile-aggressive (n = 170). Children without any known symptoms were considered well adjusted (n = 1,000). Borderline emotional (n = 105) and emotional difficulties (n = 136) were measured at age 10-12 years with the parent-administered strength and difficulties questionnaire (SDQ). Multinomial logistic regression analyses were used to adjust for potential confounding factors. We found that anxious-fearful behaviour and hostile-aggressive preschool behaviour were associated with twice the risk of school-age emotional difficulties. Comorbidity or confounding failed to explain these results. Hyperactive-distractible preschool behaviour was not associated with school-age emotional difficulties. Preschool anxious-fearful behaviour was associated with school-age emotional difficulties, suggesting internalizing symptom stability in some children from early childhood. Preschool hostile-aggressive behaviour was also associated with school-age emotional difficulties, which suggests transformation of one behavioural dimension into another through childhood, and the need to focus on both early internalizing difficulties and hostile-aggressive behaviour as risk factors for later internalizing difficulties.
Abstract: It has been suggested that prenatal stress contributes to the risk of obesity later in life. In a population-based cohort study, we examined whether prenatal stress related to maternal bereavement during pregnancy was associated with the risk of overweight in offspring during school age.
Abstract: Babies born of infertile couples, regardless of treatment, have a higher risk of preterm birth and low birthweight, conditions associated with delayed development. We examined developmental milestones in singletons as a function of parental infertility [time to pregnancy (TTP) > 12 months] and infertility treatment. From the Danish National Birth Cohort (1997-2003), we identified 37 897 singletons born of fertile couples (TTP < or = 12 months), 4351 born of infertile couples conceiving naturally (TTP > 12 months), and 3309 born after infertility treatment. When the children were about 18 months old, mothers reported 12 developmental milestones by responding to structured questions. We defined a failure to achieve the assessed milestone or the minimal numbers of milestones in a summary (motor, or cognitive/language skills) as delay. Naturally conceived children born of infertile couples had a pattern of psychomotor development similar to that of children born of fertile couples, but increasing TTP correlated with a modest delay. When the analysis was restricted to infertile couples (treated and untreated), children born after treatment showed a slight delay in cognitive/language development (odds ratio 1.24, [95% confidence interval 1.01, 1.53]) for not meeting at least three out of six cognitive/language milestones); children born after intracytoplasmic sperm injection (ICSI) had the highest estimated relative risk of delay for most milestones, especially motor milestones. These results suggest that a long TTP may be associated with a modest developmental delay. Infertility treatment, especially ICSI, may be associated with a slight delay for some of these early milestones.
Abstract: Nonright-handedness, particularly mixed-handedness, has been associated with a number of medical conditions. We examined whether handedness was associated with fecundity, measured by time to pregnancy.
Abstract: Prenatal exposure to smoking has been associated with Attention Deficit Hyperactivity Disorder (ADHD) in a number of epidemiological studies. However, mothers with the ADHD phenotype may 'treat' their problem by smoking and therefore be more likely to smoke even in a society where smoking is not acceptable. This will cause genetic confounding if ADHD has a heritable component, especially in populations with low prevalence rates of smoking since this reason for smoking is expected to be proportionally more frequent in a population with few 'normal' smokers. We compared the association in cohorts with different smoking frequencies.
Abstract: Based on hypotheses from experimental studies, we studied the association between intrauterine exposure to coffee and the risk of clinically verified hyperkinetic disorder and attention-deficit hyperactivity disorder (ADHD).
Abstract: The reproductive health of children born of infertile couples may be affected by infertility treatment or factors associated with infertility. We examined sexual maturation in children of parents with infertility.
Abstract: ADHD is a well established condition in childhood, but much less attention has been given to this diagnosis among adults. It is estimated that 2-4% of the adult population has this condition. Adults with ADHD present symptoms that differ somewhat from those presenting in childhood and they are typically characterized by problems with planning of work and daily life activities as well as social persistence. The Adult ADHD Self-report Scale (ASRS) can be used in general practice as an introduction to the diagnostic process of ADHD in a psychiatry setting and to evaluate the effect of treatment. ASRS is now available in Danish and is recommended as a screener for adult ADHD.
Abstract: Exposure to prenatal stress may affect neurodevelopment of the fetus, but whether this exposure increases the risk of cerebral palsy (CP) later in life is unknown. We aimed to examine the association between maternal bereavement during the prenatal time period and CP in childhood.
Abstract: We aimed to examine whether exposure to prenatal stress following maternal bereavement is associated with an increased risk of febrile seizures. In a longitudinal population-based cohort study, we followed 1,431,175 children born in Denmark. A total of 34,777 children were born to women who lost a close relative during pregnancy or within 1 year before the pregnancy and they were included in the exposed group. The exposed children had a risk of febrile seizures similar to that of the unexposed children (hazard ratio (HR) 1.00, 95% CI 0.94-1.06). The HRs did not differ according to the nature or timing of bereavement. Our data do not suggest any causal link between exposure to prenatal stress and febrile seizures in childhood.
Abstract: Prenatal stress has been linked to several adverse neurobehavioral outcomes, which may share a common pathophysiology with autism. We aimed to examine whether prenatal stress exposure after maternal bereavement is associated with an increased risk of autism later in life.
Abstract: Among asylum-seeking children aged 4-16 years living in the asylum centres managed by the Danish Red Cross in 2006, we investigated mental health in relation to length of stay and number of relocations. Mental health was evaluated using the Strengths and Difficulties Questionnaire (SDQ). We found that children who had been asylum-seeking for more than one year had an increased risk of having mental difficulties (odds ratio 5.5; 95% confidence interval 1.8-16.3); four or more relocations in the asylum system were also associated with a higher risk of mental problems (odds ratio 3,0; 1,4-6,7).
Abstract: Studies concerning whether exposure to low levels of maternal alcohol consumption during fetal development is related to child inattention and hyperactivity symptoms have shown conflicting results. We examine the contribution of covariates related to social adversity to resolve some inconsistencies in the extant research by conducting parallel analyses of three cohorts with varying alcohol consumption and attitudes towards alcohol use.
Abstract: We examine whether pregnancy weight (pre-pregnancy body mass index (BMI) and/or weight gain) is related to core symptoms of attention deficit hyperactivity disorder (ADHD) in school-age offspring.
Abstract: The World Health Organization has emphasized the need for research into the possible effects of radiofrequency fields in children. We examined the association between prenatal and postnatal exposure to cell phones and behavioral problems in young children.
Abstract: The process of seeking asylum and the related organisational conditions in the host country may adversely affect the children's mental health. The objective of this study was to examine the mental health of children seeking asylum in relation to organisational factors of the asylum system including length of stay and number of relocations.
Abstract: Studies indicate that children born by infertile couples have a higher frequency of congenital malformations. This may be a side effect of infertility treatment or may be caused by the underlying disease. We compared children of couples who received infertile treatment with children of infertile couples who conceived without treatment after more than 12 months of trying. We found no differences in the frequency of congenital malformations in the 2 groups, which may indicate that the underlying disease is more important than the treatment.
Abstract: We have previously observed that an increasing time to pregnancy (TTP) is associated with a reduced frequency of twin deliveries in couples not receiving infertility treatment. By using updated information, we assessed the frequencies of dizygotic (DZ) and monozygotic (MZ) twin deliveries as a function of infertility (TTP > 12 months), as well as infertility treatment.
Abstract: Exposure to severe stress in early pregnancy is associated with a lower male to female ratio (sex ratio), but whether more moderate levels of psychological discomfort have the same kind of effect is unknown. In a population based follow-up study, we aimed to test whether psychological distress was associated with the sex ratio in the offspring.
Abstract: Caffeine intake in pregnancy has been linked to adverse outcome, but evidence from non-experimental studies on impaired fetal growth remains equivocal. We carried out a randomised double blind trial to estimate the effect of reducing caffeine intake on birth weight and the length of gestation. We found no differences in mean birth weight or mean length of gestation between women randomised to caffeinated coffee and women randomised to decaffeinated coffee. A moderate reduction in caffeine intake in the second half of pregnancy has no effect on birth weight or the length of gestation.
Abstract: Attention Deficit/Hyperactivity Disorder (ADHD) affects many children, adolescents, and adults and is associated with a number of impairments. Poor academic performance is related to ADHD in clinical samples. However, it is unclear to what extent core ADHD symptoms and scholastic impairment are related in non-referred school-aged children.
Abstract: There is growing concern for the mental health of asylum-seeking children due to protracted periods of stay at asylum centres and an increasing need for psycho-social measures. The objective of this study is to survey asylum-seeking children's mental health in Denmark.
Abstract: To examine whether infertile couples (with a time to pregnancy of > 12 months), who conceive naturally or after treatment, give birth to children with an increased prevalence of congenital malformations.
Abstract: To study the association between intrauterine exposure to tobacco smoke and behavioural disorders in preschool children, primarily symptoms of inattention, hyperactivity and impulsivity but also hostile-aggressive and anxious-fearful symptoms.
Abstract: Children born extremely premature (<28 weeks) or with a very low birth weight (<1500 g) have a poorer school performance than children born at term with a normal birth weight. Much less is known about children of higher gestational ages and birth weights. We studied gestational age after 32 completed weeks and birth weight in relation to the child's school performance at the age of 10 years.
Abstract: The purpose of this study was to determine whether exposure to stressful life events was associated with changes in levels of circulating cortisol during pregnancy in a population of 603 pregnant women. The participating pregnant women filled out a questionnaire and collected a morning and evening sample of saliva in early pregnancy (median 14th gestational week) and in late pregnancy (median and 30th gestational week). They were asked to report the number of life events experienced during first and second trimester, respectively, and were asked to rate the intensity of the experienced events. Complications related to the pregnancy such as vaginal bleeding and suspected growth retardation were registered and the women were asked about concerns about their pregnancy. The salivary samples were analyzed for cortisol and the levels were higher in late than in early pregnancy. In late pregnancy women exposed to more than one life event or were concerned about pregnancy complications during second trimester had a higher evening cortisol level, whereas morning values were unaffected. After adjustment for smoking women who experienced more than one very stressful life event had 27% higher evening cortisol concentrations (95% confidence intervals: 1-59%). Women with worries about pregnancy complications had 27% (95% confidence intervals: 2-57%) higher levels. In early pregnancy women reporting stressful life events did not have higher evening cortisol levels, but tended to have a blunted morning HPA response. In conclusion, we found differences in the associations between chronic stress in early and late pregnancy and cortisol levels indicating that the response to chronic stress is dependent on the stage of the pregnancy.
Abstract: Maternal smoking during pregnancy may increase the risk for behavioral disorders. The aim of this study was to investigate the association between smoking during pregnancy and hyperkinetic and attention-deficit/hyperactivity disorder in the offspring in a large population-based study.
Abstract: The Strengths and Difficulties Questionnaire (SDQ) has been translated into the different Nordic languages between 1996 and 2003. During the past few years, SDQs have been completed for nearly 100,000 children and adolescents in population-based studies as well as in clinical samples. The largest studies have been performed in Norway and Denmark, and in these countries the diagnostic interview DAWBA has also been used in conjunction with the SDQ.
Abstract: The objective of this study was to examine whether social risk factors adjusted for gender and some well-known perinatal risk factors were related to parental descriptions of deviant behaviour in 3(1/2)-year-old children. The study was a prospective cohort study of 1345 mothers enrolled during early pregnancy. Parents answered a questionnaire and children's behavioural difficulties were categorized into the following groups; "hyperactive-distractible", "hostile-aggressive" and "anxious-fearful" following a modified Behar scale. The male gender was found to be related to a description of all kinds of deviant behaviour. Having a family member experiencing employment difficulties was the factor most closely related to "hyperactive-distractible" behaviour. Familial stress due to lack of time, experience of divorce and mothers in excess of 35 years at childbirth were found to be related to "hostile-aggressive" behaviour, but male gender was the most closely related. Social disadvantage was not found to be related to "anxious-fearful" behaviour.
Abstract: The purpose of this review was to examine the literature assessing the relationship between prenatal exposure to nicotine, alcohol, caffeine, and psychosocial stress during pregnancy to the risk of developing behavioral problems related to attention deficit hyperactivity disorder (ADHD) in childhood.
Abstract: A strong association between stress in pregnancy and small head circumference in infants at birth was reported in 1994. This important finding has never been replicated. In a follow-up study of 4211 participants with singleton pregnancies, information on life events was collected twice during pregnancy and head circumference measured shortly after birth following standard procedures. No association was found between experienced or perceived stress as a result of life events during pregnancy and head circumference in the infants. In conclusion, stress in pregnancy may influence foetal brain development in many ways, but we found no support for an effect on the size of the brain as measured by head circumference at birth.
Abstract: We did a follow-up study based upon a regional prescription register in Denmark. We identified all 435 women who in the period 1991-1996 had redeemed a prescription for CNS drugs during pregnancy. Among the rest of the pregnant women we randomly selected 1304 women who also had given birth to a child in the same region and period. We looked up the local health nurses Boel test results which were available for about 80%. Any abnormal test result was seen much more frequently among exposed (16%) than for not exposed (4%). The study has several limitations but raises concern that should be addressed in other and better designed studies.
Abstract: Animal studies suggest that psychological factors may interfere with the development of brain asymmetry during gestation. We evaluated whether psychological exposure in pregnancy was associated with mixed-handedness in the offspring. In a follow-up design study, 824 Danish-speaking women with singleton pregnancies provided information on psychological distress and the occurrence of life events in the early second and third trimesters of pregnancy. Handedness of the children was based on maternal reports when the children were 3 years of age. Among the 419 males and 405 females, 7% and 5% respectively were mixed-handed whereas mixed-handedness was found in 3% of the parents. Psychological distress in the third trimester as well as higher levels of stressful life events were related to a higher prevalence of mixed-handedness in the offspring. About 16% of the women reported more than one life event in the third trimester of pregnancy and among the offspring of these women 11% were mixed-handed (odds ratio = 2.3; 95% confidence interval 1.2 to 4.4). Women who at the same time reported a high level of distress and stressful life events, had a three- to four-fold higher prevalence of mixed-handedness in their offspring.
Abstract: Several studies have suggested that breastfeeding has a long-term influence on brain development. However, interpretation of these findings is complicated by the presence of many potential confounding factors. Only a few studies have examined infants before 1 y of age, although very early assessment might reduce the role of environmental influence. We investigated the association between exclusive breastfeeding and three developmental milestones related to general and fine motor skills and early language development at the age of 8 mo. We followed 1656 healthy, singleton, term infants, with a birthweight of at least 2500 g, born between May 1991 and February 1992 in Aarhus, Denmark. Information was collected at 16 wk gestation, at delivery and when the infant was 8 mo old. Motor skills were evaluated by measurement of crawling and pincer grip. Early language development was defined as the ability to babble in polysyllables. The proportion of infants who mastered the specific milestones increased consistently with increasing duration of breastfeeding. The relative risk for the highest versus the lowest breastfeeding category was 1.3 (95% CI: 1.0-1.6) for crawling, 1.2 (95% CI: 1.1-1.3) for pincer grip and 1.5 (95% Cl: 1.3-1.8) for polysyllable babbling. Little change was found after adjustment for confounding. In conclusion, our data support the hypothesis that breastfeeding benefits neurodevelopment.
Abstract: Animal experiments suggest that the fetal brain is sensitive to nicotine. Although much attention has been given to the relation between cigarette smoking during pregnancy and neurodevelopment in children, this remains controversial. Our study describes the relationship between maternal cigarette smoking during pregnancy and babbling abilities of the 8-month-old infant. In a longitudinal cohort, information was collected at the 16th week of gestation, at delivery and when the infant was about 8 months old. At this age babbling abilities of the infant were evaluated by a health visitor during a home visit. Singleton infants without any disability born at Aarhus University Hospital, Denmark, 1991-92 and still living in the Community of Aarhus at the age of 8 months were eligible (n = 2302). Complete follow-up was obtained for 1871 children (81.3%). A dose-response-like relationship between number of cigarettes smoked per day during pregnancy and babbling abilities was found after controlling for potential confounders. Smoking 10 or more cigarettes per day during pregnancy almost doubled the risk (odds ratio [OR] = 2.0, 95% confidence interval [CI] 1.1-3.6) of the infant being a non-babbler at the examination at 8 months. Among children who were breast fed for less than 4 months this risk was even higher (OR = 2.7, CI 1.3-5.8).
Abstract: Smoking during pregnancy is harmful to the health of the fetus and the newborn. Smoking increases the risk of low birthweight, preterm delivery and perinatal death. In developed countries smoking during pregnancy is regarded as the single most important risk factor for which it is possible to intervene. We reviewed the Scandinavian and English randomized controlled intervention studies directed towards smoking cessation during pregnancy. The intervention studies were classified according to the method of intervention namely antismoking advice, self-help manuals, measurements of smoking dependent chemical factors and multifactorial methods. We conclude that it is possible to reduce smoking during pregnancy only by an efficient and personal effort performed by a committed person towards each pregnant woman.
