Cohort studies often report findings on children with Attention Deficit Hyperactivity Disorder (ADHD) but may be biased by self-selection. The representativeness of cohort studies needs to be investigated to determine whether their findings can be generalised to the general child population. The aim of the present study was to examine the representativeness of child ADHD in the Norwegian Mother and Child Cohort Study (MoBa).
The study population was children born between January 1, 2000 and December 31, 2008 registered with hyperkinetic disorders (hereafter ADHD) in the Norwegian Patient Registry during the years 2008-2013, and two groups of children with ADHD were identified in: 1. MoBa and 2. The general child population. We used the multiaxial International Classification of Diseases (ICD-10) and compared the proportions of comorbid disorders (axes I-III), abnormal psychosocial situations (axis V) and child global functioning (axis VI) between these two groups. We also compared the relative differences in the multiaxial classifications for boys and girls and for children with/without axis I comorbidity, respectively in these two groups of children with ADHD.
A total of 11 119 children were registered with ADHD, with significantly fewer in MoBa (1.45%) than the general child population (2.11%), p
Numerous studies have investigated the prevalence of neurologic and neurodevelopmental disorders individually, but few have examined them collectively, and there is uncertainty as to what extent they overlap.
The study has determined the proportions of children aged 0 to 11 years with diagnoses of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), epilepsy, and cerebral palsy (CP) in Norway. The data were obtained from the Norwegian Patient Register, which is nationwide and contains diagnoses assigned by Norwegian specialist health services (hospitals and outpatient clinics). The Norwegian Patient Register started collecting individual-level data in 2008, and the follow-up period for the study is years 2008 through 2010.
For ASD, ADHD, and epilepsy, the proportions were highest in the oldest children. At age 11 years, the incidence was 0.7% for ASD, 2.9% for ADHD, and 0.9% for epilepsy. The cumulative incidence is likely to be higher because some cases diagnosed before 2008 were probably missed. For CP, the proportions were ~0.3% for age = 5 years. There was considerable overlap between diagnoses. For all disorders, boys had a significantly increased risk. In school-age children (aged 6-11 years) the male/female ratio was 4.3 for ASD, 2.9 for ADHD, 1.2 for epilepsy, and 1.3 for CP.
The findings demonstrate the significant burden of disease associated with neurologic and neurodevelopmental disorders in children and that this burden is disproportionately skewed toward boys.
Anxiety disorders and attention deficit/hyperactivity disorder (ADHD) develop before school age, but little is known about early developmental pathways. Here we test two hypotheses: first, that early signs of anxiety and ADHD at 18 months predict symptoms of anxiety and ADHD at age 3½ years; second, that emotional dysregulation at 18 months predicts the outcome of co-occurring anxiety and ADHD at age 3½ years. The study was part of the prospective Norwegian Mother and Child Cohort Study (MoBa) at the Norwegian Institute of Public Health. The 628 participants were clinically assessed at 3½ years. Questionnaire data collected at 18 months were categorized into early behavioural scales of anxiety, ADHD, and emotional dysregulation. We investigated continuity in features of anxiety and ADHD from 18 months to 3½ years of age through logistic regression analyses. Anxiety symptoms at 3½ years were predicted by early signs of anxiety (Odds ratio (OR) = 1.41, CI = 1.15-1.73) and emotional dysregulation (OR = 1.33, CI = 1.15-1.54). ADHD symptoms at 3½ years were predicted by early signs of ADHD (OR = 1.51, CI = 1.30-1.76) and emotional dysregulation (OR = 1.31, CI = 1.13-1.51). Co-occurring anxiety and ADHD symptoms at 3½ years were predicted by early signs of anxiety (OR = 1.43, CI = 1.13-1.84), ADHD (OR = 1.30, CI = 1.11-1.54), and emotional dysregulation (OR = 1.34, CI = 1.13-1.58). We conclude that there were modest continuities in features of anxiety and ADHD through early preschool years, while emotional dysregulation at age 18 months was associated with symptoms of anxiety, ADHD, and co-occurring anxiety and ADHD at age 3½ years.
The objective of this study was to examine co-occurrence of ADHD and anxiety in preschool children.
The data collection was part of the Norwegian Mother and Child Cohort Study (MoBa) at the Norwegian Institute of Public Health. After a screening for ADHD symptoms at 36 months, participants were clinically assessed at age 36 to 44 months. Psychiatric symptoms of ADHD and anxiety were derived from the Preschool Age Psychiatric Assessment (PAPA) interview.
In preschoolers with ADHD symptoms, 33% were reported to have symptoms of anxiety. Children with symptoms of ADHD and anxiety had more severe ADHD symptomatology, and particularly more inattentive symptoms compared with children with ADHD symptoms and no anxiety.
Clinicians should be aware of the frequent overlap between symptoms of anxiety and ADHD in preschoolers as different intervention strategies may be required.
Patterns of co-occurrence between ADHD, Oppositional Defiant Disorder (ODD), and Conduct Disorder (CD) were examined in a sample of non-referred preschool children. ADHD subtypes and sex differences were also explored.
Children aged 3.5 years ( n = 1,048) with high scores on ADHD characteristics were recruited from the Norwegian Mother and Child Cohort Study and clinically assessed, including a semi-structured psychiatric interview.
In children with ADHD, concurrent ODD was present more often than CD (31% vs. 10%), but having ADHD gave higher increase in the odds of CD than of ODD (ODD: odds ratio [OR] = 6.7, 95% confidence interval [CI] = [4.2, 10.8]; CD: OR = 17.6, 95% CI = [5.9, 52.9]). We found a greater proportion of children having the combined ADHD subtype as well as more severe inattentiveness among children with co-occurring CD compared with ODD. Sex differences were minor.
There are important differences in co-occurring patterns of ODD and CD in preschool children with ADHD.
In 2012, we published an overview of the prevalence of developmental disorders and neurological diseases in children in Norway, which was unknown at the time. In this article we will compare diagnostics and treatment across counties and institutions.
The prevalence across counties of autism spectrum disorders, ADHD, epilepsy and cerebral palsy in children aged 0-12 was estimated with the aid of data from the Norwegian Patient Register for the years 2008-11.
In the age group 6-12 years, nationwide prevalence amounted to 0.6% for autism spectrum disorders, 2.0% for ADHD, 0.9% for epilepsy and 0.3% for cerebral palsy. In total, 5.0% of all twelve-year-olds were registered with one or more of these diagnoses. The prevalence of autism spectrum disorders and ADHD varied between the counties, from 0.3% to 1.5% for autism spectrum disorders and from 1.1% to 3.5% for ADHD. For epilepsy and cerebral palsy there was little variation between the counties. Diagnostics and treatment of these four conditions are spread over 29 somatic hospitals and 102 units for child and youth psychiatry.
The variations across counties in the prevalence of autism spectrum disorders and ADHD are most likely due to variations in diagnostic practices. We ask whether it is appropriate to spread the provision of treatment across such a high number of institutions.
Comment In: Tidsskr Nor Laegeforen. 2013 Oct 1;133(18):190424084945
Early symptoms of attention deficit/hyperactivity disorder (ADHD) and oppositional-defiant disorder (ODD) are associated with deficits in cognitive self-regulatory processes or executive functions (EF)s. However, the hypothesis that neurocognitive deficits underlying the two disorders are already evident during early preschool years still has limited empirical support. The present study investigated associations between symptoms of ADHD and/or ODD and two core EFs, inhibition and working memory, in a large nonclinical sample of 3-year old children.
Participants were 1045 children (554 boys, age 37-47 months), recruited from the population based Norwegian Mother and Child Cohort Study (MoBa). Relations between behavioral symptoms and measures of inhibition and working memory were studied both categorically and dimensionally.
Children with co-occurring symptoms of ADHD and ODD performed at a significantly lower level than typically developing children in 4 out of 5 EF measures. Symptoms of ADHD, both alone and in combination with ODD, were associated with reduced performance on tests of inhibition in the group comparisons. Dimensional analyses showed that performance within both EF domains contributed to variance primarily in ADHD symptom load. The associations between test results and behavioral symptoms remained significant after gender and verbal skills had been controlled.
Young preschoolers show the same pattern of relations between EF and behavioral symptoms of ADHD and/or ODD as previously described in older children diagnosed with ADHD and/or ODD. Effect sizes were generally small, indicating that measures of EF have limited clinical utility at this stage in development.
Little is known about cognition in preschoolers with ADHD and language delay (LD). The objective was to investigate cognitive functions in preschoolers with ADHD symptoms and LD compared with children with ADHD symptoms only and to estimate the frequency of children with ADHD symptoms, co-occurring language delay, and delays on cognitive measures.
Participants were recruited from the Norwegian Mother and Child Cohort Study. The teacher report of expressive language and the cognitive tests from 119 3-year-old children with parent reported ADHD symptoms and LD were compared with those of 258 children with ADHD symptoms only.
The ADHD + LD group performed significantly worse than the ADHD group on most language-related measures. There were no differences between the groups on most nonverbal measures. Single measures had a limited potential of differentiating between the groups.
ADHD symptoms and co-occurring LD in preschoolers were characterized by cognitive deficits associated with both disorders, not with global neurodevelopmental delay.
Current knowledge about the relationship between mild to moderately inadequate maternal iodine intake and/or supplemental iodine on child neurodevelopment is sparse. Using information from 77,164 mother-child pairs in the Norwegian Mother and Child Cohort Study, this study explored associations between maternal iodine intake and child attention-deficit/hyperactivity disorder (ADHD) diagnosis, registered in the Norwegian Patient Registry and maternally-reported child ADHD symptoms at eight years of age. Pregnant women reported food and supplement intakes by questionnaire in gestational week 22. In total, 1725 children (2.2%) were diagnosed with ADHD. In non-users of supplemental iodine (53,360 mothers), we found no association between iodine intake from food and risk of child ADHD diagnosis (p = 0.89), while low iodine from food (
Measurement of Total and Free Urinary Phenol and Paraben Concentrations over the Course of Pregnancy: Assessing Reliability and Contamination of Specimens in the Norwegian Mother and Child Cohort Study.
Exposures to environmental phenols and parabens may be harmful, especially in utero. Prior studies have demonstrated high within-person variability of urinary concentrations across pregnancy.
We sought to measure phenol and paraben biomarker concentrations for the Norwegian Mother and Child Cohort (MoBa) study, assess within-person variability, and investigate any possible external phenol or paraben contamination of specimens.
We collected three spot urine samples at approximately 17, 23, and 29 weeks gestation in a hospital setting and added a preservative containing ethyl paraben. We measured urinary concentrations and within-person variability for phenols and parabens in a MoBa sample (n = 45), including a subgroup of 15 participants previously randomly selected for a bisphenol A (BPA) exposure study who had unusually high total BPA concentrations. Additionally, we compared reliability results for total, conjugated, and free concentrations of phenolic compounds.
We detected total and free BPA, butyl paraben, propyl paraben, and methyl paraben in 100% of samples, total benzophenone-3 in 95% of samples, and infrequently detected free benzophenone-3 and total and free 2,4-dichlorophenol and 2,5-dichlorophenol. Intraclass correlation coefficients (ICCs) for total, conjugated, and free concentrations ranged from relatively low for BPA to moderate for propyl paraben. ICCs were generally similar overall and by subgroup.
Using conjugated concentrations improved reliability estimates only for BPA. Measuring total and free concentrations, an approach that may be useful for future studies, allowed us to identify likely BPA and butyl paraben contamination of archived MoBa urine specimens.
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