Biological predictors and co-morbidity of attention deficit and hyperactivity disorder in extremely low birthweight infants at school

Psychiatric traits and intracerebral hemorrhage: A Mendelian randomization study

BACKGROUND

Psychiatric traits have been associated with intracerebral hemorrhage (ICH) in observational studies, although their causal relationships remain uncertain. We used Mendelian randomization analyses to infer causality between psychiatric traits and ICH.

METHODS

We collected data from genome-wide association studies of ICH (n = 361,194) and eight psychiatric traits among Europeans, including mood swings (n = 451,619), major depressive disorder (n = 480,359), attention-deficit/hyperactivity disorder (n = 53,293), anxiety (n = 459,560), insomnia (n = 462,341), schizophrenia (n = 77,096), neuroticism (n = 374,323), and bipolar disorder (n = 51,710). We performed a series of bidirectional two-sample Mendelian randomization and related sensitivity analyses. A Bonferroni corrected threshold of p < 0.00625 (0.05/8) was considered to be significant, and p < 0.05 was considered suggestive of evidence for a potential association.

RESULTS

Mendelian randomization analyses revealed suggestive positive causality of mood swings on ICH (odds ratio = 1.006, 95% confidence interval = 1.001-1.012, p = 0.046), and the result was consistent after sensitivity analysis. However, major depressive disorder (p = 0.415), attention-deficit/hyperactivity disorder (p = 0.456), anxiety (p = 0.664), insomnia (p = 0.699), schizophrenia (p = 0.799), neuroticism (p = 0.140), and bipolar disorder (p = 0.443) are not significantly associated with the incidence of ICH. In the reverse Mendelian randomization analyses, no causal effects of ICH on mood swings (p = 0.565), major depressive disorder (p = 0.630), attention-deficit/hyperactivity disorder (p = 0.346), anxiety (p = 0.266), insomnia (p = 0.102), schizophrenia (p = 0.463), neuroticism (p = 0.261), or bipolar disorder (p = 0.985) were found.

CONCLUSION

Our study revealed that mood swings are suggestively causal of ICH and increase the risk of ICH. These results suggest the clinical significance of controlling mood swings for ICH prevention.

Association of Attention Deficit/Hyperactivity Disorder With Events Occurring During Pregnancy and Perinatal Period

Background: The relationship of events occurring during pregnancy and perinatal period with attention deficit/hyperactivity disorder (ADHD) is not clear. Thus, the focus of the current study was to examine the effects of events occurring during pregnancy and perinatal period on ADHD.

Methods: A two-phase cross-sectional study was performed across 13 schools in Changsha and Yiyang cities from March to December, 2014. We preliminarily screened all students using CBCL and established the diagnosis using Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID) and the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). A total of 3,418 questionnaires were effectively completed in this study.

Results: History of threatened abortion (TA) [odds ratio (OR): 1.707 (1.201–2.426)] (vs. No-TA) and neonatal asphyxia (NA) [OR: 2.497(1.225–5.09)] (vs. health) showed a positive association with ADHD. On subgroup analysis, TA [OR: 2.216 (1.458–3.369)] (vs. No-TA) was a risk factor for ADHD without comorbidity; instrumental delivery [OR: 2.748 (1.057–7.142)] (vs. natural birth) and NA [OR: 2.789 (1.222–6.361)] (vs. health) were risk factors for ADHD in the subgroup of ADHD with comorbidity; TA (vs. no-TA) and NA (vs. health) were risk factors for ADHD among male students [ORs: 2.232 (1.439–3.462) and 2.808 (1.115–7.068), respectively], while low birth weight (LBW) (vs. normal birth weight) was a risk factor [OR: 2.054 (1.063–3.967)] for ADHD among female students.

Conclusion: TA was a risk factor for ADHD in the absence of comorbid conditions; instrumental delivery and NA were risk factors for ADHD in the subgroup of ADHD with comorbidity; TA and NA were risk factors for ADHD among male students. LBW was a risk factor for ADHD among female students.

Associations of atopic dermatitis and asthma with child behaviour: Results from the PROBIT cohort

BACKGROUND

Conflicting findings from studies evaluating associations of allergic disease with child behaviour require longitudinal studies to resolve.

OBJECTIVE

To estimate the magnitude of associations of atopic dermatitis (AD) in infancy, and symptoms of asthma and AD at 6.5 years, with child behaviour at 6.5 years.

METHODS

Secondary cohort analysis of the Promotion of Breastfeeding Intervention Trial (PROBIT). PROBIT enrolled 17 046 infants at birth and followed them up at 6.5 years (n = 13 889). Study paediatricians collected data on infantile AD at repeated follow-up examinations during the first year of life. At 6.5 years, paediatricians performed skin prick tests and parents reported asthma and AD symptoms during the prior year. In addition, parents and teachers completed the Strength and Difficulties Questionnaire, which includes scales on hyperactivity/inattention, emotional problems, conduct problems, peer problems and prosocial behaviours.

RESULTS

Physician-diagnosed AD in the first year of life was not associated with increased risk for behavioural problems at 6.5 years. Emotional problems at 6.5 years were more common among children with AD symptoms (OR: 2.24, 95% CI: 1.62-3.12) and asthma symptoms (OR: 1.45; 95% CI: 1.07-1.96) during the past year at 6.5 years and ORs for children with symptoms of more severe AD and asthma were also higher. AD in the past year was also associated with probable hyperactivity/inattention disorder at 6.5 years (OR: 2.05; 95% CI: 1.09-3.84). Other subscales of the SDQ were not related to asthma or AD symptoms during the past year.

CONCLUSIONS AND CLINICAL RELEVANCE

Children with AD symptoms were at higher risk for concomitant hyperactivity/inattention and emotional disorder, and children with asthma symptoms were at higher risk of having concomitant emotional problems. However, AD during infancy did not predict childhood behaviours.

A Meta-Analysis of the Association Between Birth Weight and Attention Deficit Hyperactivity Disorder

A large body of work has investigated the association between birth weight and ADHD and has resulted in mixed findings with regard to the direction and magnitude of this association. Despite the vast amount of research on this topic, a comprehensive and systematic quantification of the association between birth weight and ADHD has yet to be undertaken. A meta-analysis of 88 unique studies (N = 4,645,482) was conducted to quantify the overall effect size of birth weight on ADHD symptoms. Several variables were examined as moderators that may contribute to systematic variation in effect sizes. Overall, birth weight was found to have a small, but significant, association with ADHD symptoms such that individuals born at lower birth weights manifested greater symptoms of ADHD (r = -0.15). Sample type, mean birth weight of the sample, geographic region, the informant of ADHD symptoms, ADHD symptom measurement method, and race were all found to contribute significantly to heterogeneity in effect sizes. Notably, several early life risk factors previously found to be associated with both ADHD and birth weight, gestational age and prenatal smoking exposure, were not found to contribute to heterogeneity in effect sizes. The findings of the current analyses align with the growing recognition that early life adversity contributes to neurodevelopmental difficulties, and the findings highlight the importance of a better understanding of the mechanisms underlying the association between early life risk factors and adverse neurodevelopmental sequela, such as that observed in ADHD.

Research Review: The role of obstetric and neonatal complications in childhood attention deficit and hyperactivity disorder - a systematic review

BACKGROUND

Attention deficit and hyperactivity disorder (ADHD) is a developmental disorder characterized by an inability to sustain attention, activity levels and impulse control, and, according to the latest studies, the prevalence is about 8% and in some countries less than 1%. Currently, it is well-known that complications during the perinatal period have significant implications on child's physical and mental health. Purpose of the present paper is to review the literature about the association between perinatal complications and future risk of an ADHD diagnosis.

METHODS

A research in the main database sources has been conducted to obtain a systematic review on the perinatal risk factors of ADHD.

RESULTS

Among perinatal complications, available data indicate low birth weight (LBW) (Cohen's d effect size range: 0.31-1.64-small effect size) and preterm birth (PB) (range d: 0.41-0.68) as the most important factors associated with a future diagnosis of ADHD.

CONCLUSIONS

PB and LBW children should be carefully monitored for an early diagnosis of ADHD limiting the impact of the disease in life span. A systematic review focusing on these risk factors have not been published until now, in the next future preventive strategies should be developed in order to minimize ADHD onset.

Annual research review: Infant development, autism, and ADHD--early pathways to emerging disorders

BACKGROUND

Autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD) are two of the most common neurodevelopmental disorders, with a high degree of co-occurrence.

METHODS

Prospective longitudinal studies of infants who later meet criteria for ASD or ADHD offer the opportunity to determine whether the two disorders share developmental pathways.

RESULTS

Prospective studies of younger siblings of children with autism have revealed a range of infant behavioral and neural markers associated with later diagnosis of ASD. Research on infants with later ADHD is less developed, but emerging evidence reveals a number of relations between infant measures and later symptoms of inattention and hyperactivity.

CONCLUSIONS

We review this literature, highlighting points of convergence and divergence in the early pathways to ASD and ADHD.

Nonallergic comorbidities of atopic eczema: an overview of systematic reviews

The aims of this overview are to synthesize the current evidence of published systematic reviews (SRs) on nonallergic comorbidities of atopic eczema (AE). EMBASE and MEDLINE were searched for SRs published from inception to November 2012. SRs were selected independently based on predefined inclusion criteria. Methodological quality of SRs included was assessed by two independent reviewers using the Revised Assessment of Multiple Systematic Reviews (R-AMSTAR) checklist. Nine SRs met all inclusion criteria. Six reviews addressing the association between AE and cancer suggest a decreased risk of glioma, meningioma, and acute lymphoblastic leukemia in patients with current or previous AE. One SR reported a consistent positive association of AE with attention-deficit hyperactivity disorder (ADHD). Diabetes mellitus type 1 and multiple sclerosis (MS) were not significantly related to AE in reviews based on cross-sectional and case-control studies. Patients with AE appear to be at decreased risk of brain tumors. The relationship of AE with Th1- and Th17-mediated (auto-)inflammatory conditions such as diabetes mellitus type 1 and MS should be clarified in prospective observational studies. Children with AE are at increased risk of ADHD. SRs on the risk of depression and Th17-mediated disorders such as inflammatory bowel disease of patients with AE are missing.

Prevalence of attention-deficit/hyperactivity disorder in patients with pediatric allergic disorders: a nationwide, population-based study

BACKGROUND

Allergic disorders are common, chronic conditions in pediatric populations. The characteristic symptoms of allergic disorders mainly include bronchial asthma (BA), allergic rhinitis (AR), and atopic dermatitis (AD), all of which may disturb sleep, leading to daytime inattention, irritability, and hyperactivity, which are also components of attention-deficit/hyperactivity disorder (ADHD). Conflicting data exist in the literature regarding the relationship between ADHD and allergic disorders. The aim of this nationwide, population-based study is to examine the prevalence and risk of developing ADHD among allergic patients in a pediatric group.

METHODS

Data from a total of 226,550 pediatric patients under 18 years of age were collected from Taiwan's National Health Insurance Research Database recorded from January 1 to December 31, 2005 and analyzed. We calculated the prevalence of allergic diseases based on various demographic variables, including ADHD. We also used multivariable logistic regression to analyze the risk factors of ADHD.

RESULTS

In 2005, the period prevalence rates of allergic disorders and ADHD in persons under the age of 18 were 21.5% and 0.6%, respectively. Pediatric patients with allergic disorder(s) had a substantially increased rate of developing ADHD (p < 0.001) in terms of period prevalence and odds ratio (OR). This significance existed across various demographic groups regardless of age, gender, location, or degree of urbanization of their residence. BA and AR, but not AD, were determined to be risk factors for ADHD. Co-morbidities of allergic disorders, including AR+AD, AR+BA and AR+BA+AD, but not BA+AD, were also determined to increase the risk of ADHD.

CONCLUSION

Allergic disorders appear to increase the risk of ADHD in pediatric patients. Our detailed analysis shows that the main contributing factor is AR. Co-morbidity with AD, BA, and BA+AD in AR patients further increases the risk of ADHD.

Preterm birth and childhood psychiatric disorders

Epidemiologic studies have, for many years, identified preterm birth as a significant risk factor for psychiatric disorders. There has been a recent resurgence of interest in neurobehavioral outcomes after preterm birth. In this article, we review clinical cohort studies of the prevalence, etiology, and risk factors for psychiatric sequelae in ex-preterm children. Studies using diagnostic psychiatric evaluations are few in number but typically report a 3- to 4-fold increased risk for disorders in middle childhood. Our review of studies reveals a "preterm behavioral phenotype" characterized by an increased risk for symptoms and disorders associated with inattention, anxiety, and social difficulties. The most contemporary studies have also reported a markedly increased prevalence of autism spectrum disorders (ASD) in preterm populations. Our examination of the correlates and comorbidities of psychiatric disorders is indicative of a different causative pathway that may be associated with altered brain development after preterm birth. Despite the low population attributable risk, the frequency of these symptoms and disorders means that psychiatric screening is likely to be beneficial in this vulnerable population.

Is atopic disease a risk factor for attention-deficit/hyperactivity disorder? A systematic review

The increase in prevalence and burden of atopic diseases, i.e. eczema, rhinitis, and asthma over the past decades was paralleled by a worldwide increase in attention-deficit/hyperactivity disorder (ADHD) diagnoses. We systematically reviewed epidemiologic studies investigating the relationship between atopic diseases and ADHD. Electronic literature search in PubMed and PsycINFO (until 02/2010) supplemented by handsearch yielded 20 relevant studies totaling 170,175 individuals. Relevant data were abstracted independently by two reviewers. Six studies consistently reported a positive association between eczema and ADHD with one study suggesting effect modification by sleeping problems. Twelve studies consistently found a positive association between asthma and ADHD, which, however, appeared to be at least partly explained (confounded) by concurrent or previous eczema. Rhinitis and serum-IgE level were not related to ADHD symptomatology. We conclude that not atopic disease in general, but rather that eczema appears to be independently related to ADHD. Conclusions about temporality and whether the observed association constitutes a causal relationship are impossible, as most studies were cross-sectional (n = 14; 70%) or case-control studies without incident exposure measurement (n = 5; 25%). Another methodological concern is that the criteria to define atopic disease and ADHD were inadequate in most studies. A failure to adjust for confounders in the majority of studies was an additional limitation so that meta-analysis was not indicated. Future interdisciplinary high-quality prospective research is needed to better understand the mechanisms underlying the relationship between eczema and ADHD and to eventually establish targeted preventive and treatment strategies.

Behavioral outcomes of extremely low birth weight children at age 8 years

OBJECTIVE

To describe the prevalence of behavioral problems and symptomatology suggestive of Autism and Asperger's disorders at age 8 years among extremely low birth weight (ELBW, <1 kg) children, born 1992 through 1995.

METHOD

Parent reports of the behavior of 219 ELBW (mean birth weight, 810 g; gestational age 26 weeks) were compared with 176 normal birth weight children of similar maternal sociodemographic status, sex, and age. Behavior was assessed via the Child Symptom Inventory that includes both Symptom Severity Scores and scores meeting DSM-IV criteria for disorders.

RESULTS

ELBW compared with normal birth weight children had significantly higher mean Symptom Severity Scores for the inattentive, hyperactive, and combined types of attention-deficit hyperactivity disorder (all p < .001) as well as higher scores for Generalized Anxiety (p < .01) and Autistic (p < .001) and Asperger's (p < .01) disorders. When DSM-IV criteria were considered, ELBW children also had significantly higher rates of attention-deficit hyperactivity disorder of the inattentive (10% vs 3%, p < .01) and combined (5% vs 0.6%, p < .05) types.

CONCLUSIONS

Attention-deficit hyperactivity disorder, mainly the inattentive type is prevalent among ELBW children. Our findings of an increase in symptoms pertaining to Autistic and Asperger's disorders at school age agree with recent reports of others during early childhood. Early identification and intervention for these problems might improve child functioning and ameliorate parent and child distress.

Antenatal magnesium sulphate neuroprotection in the preterm infant

Very preterm infants have high rates of neurological impairments and disabilities. These rates have not diminished as the survival rates have improved. Basic science research suggests that magnesium sulphate before birth can be neuroprotective for the preterm fetus. Some, but not all, observational studies in humans also suggest a protective effect of antenatal magnesium sulphate on cerebral palsy. Four randomised controlled trials of antenatal magnesium sulphate have reported long-term neurological effects in surviving infants, but only one of these was designed specifically to evaluate the long-term effects of treatment. These studies found that, overall, antenatal magnesium sulphate therapy had no significant effect on paediatric mortality or neurological outcomes in the first few years of life, including cerebral palsy, but it was found to lower the rate of motor problems at 2 years of age in one study. The role for antenatal magnesium sulphate therapy as a neuroprotective agent for the preterm fetus is not yet established.

Smoking during pregnancy and attention-deficit/hyperactivity disorder, predominantly inattentive type: a case-control study

OBJECTIVE

Few previous studies assessed specifically attention-deficit/hyperactivity disorder, predominantly inattentive subtype (ADHD-I) in nonreferred samples. This study investigated the association between ADHD-I and prenatal exposure to nicotine.

METHOD

In a case-control study performed between September 2002 and April 2005, we assessed a nonreferred Brazilian sample of 100 children and adolescents with ADHD-I and 100 non-ADHD controls (6-18 years old). Cases and controls, matched by gender and age, were screened using teacher reports in the Swanson, Nolan, and Pelham-IV (SNAP-IV) scale. They were systematically evaluated through structured diagnostic interviews. Prenatal exposure to nicotine and potential confounding factors were evaluated by direct interview with mothers.

RESULTS

Adjusting for confounding factors (maternal ADHD, oppositional defiant disorder, birth weight, and alcohol use during pregnancy), children whose mothers smoked>or=10 cigarettes per day during pregnancy presented a significantly higher odds ratio for ADHD-I than children who were not exposed to nicotine during pregnancy (odds ratio 3.44; 95% confidence interval 1.17-10.06). Dimensional analyses showed significantly higher inattentive scores in subjects whose mothers smoked>or=10 cigarettes per day than in others after adjusting for confounding factors (p=.002).

CONCLUSIONS

In a nonreferred sample, the authors expanded to ADHD-I previous findings documenting the association between prenatal exposure to nicotine and broadly defined ADHD in clinical samples.

Cervical kyphosis is a possible link to attention-deficit/hyperactivity disorder

OBJECTIVE

To discuss the case of a patient who was diagnosed with attention-deficit/hyperactivity disorder (ADHD) by a general practitioner and was treated with chiropractic care.

CLINICAL FEATURES

A 5-year-old patient was diagnosed with ADHD and treated by a pediatrician unsuccessfully with methylphenidate (Ritalin), Adderall, and Haldol for 3 years. The patient received 35 chiropractic treatments during the course of 8 weeks. A change from a 12 degrees C2-7 kyphosis to a 32 degrees C2-7 lordosis was observed after treatment. During chiropractic care, the child's facial tics resolved and his behavior vastly improved. After 27 chiropractic visits, the child's pediatrician stated that the child no longer exhibited symptoms of ADHD. The changes in structure and function may be related to the correction of cervical kyphosis.

CONCLUSION

The patient experienced significant reduction in symptoms. Additionally, the medical doctor concluded that the reduction in symptoms was significant enough to discontinue the medication. There may be a possible connection that correction of cervical kyphosis in patients with ADHD may produce a desirable clinical outcome.

Behavioral and social development of children born extremely premature: 5-year follow-up

A cohort of extremely prematurely born children and matched term controls was assessed at 5 years of age. The parents completed a questionnaire on their behavioral and social development. The purpose was to illuminate whether the children's general intellectual ability and parental sensitivity were associated with behavioral and social development. The index children exhibited more hyperactive behavior and had poorer social skills than the controls. Lower Full Scale IQ (FSIQ) was associated with outward reacting and hyperactive behavior and poorer social skills. Sensitive parenting was associated with less outward reacting and less hyperactive behavior. When controlling for differences in FSIQ and parental sensitivity, the index children persisted to have an increased risk of exhibiting hyperactive behavior but not poorer social skills. The index children with normal intellectual development, however, did not exhibit more behavioral problems or poorer social skills than the control children did.

Special education services and school performance in a regional cohort of low-birthweight infants at age nine

Previous research has shown that low birthweight is a predictor of several adverse educational outcomes, including special educational placement, by middle school age. Most low-birthweight follow-up studies that have extended to school age have focused on very small infants-- < 1500 or < 1000 g; less is known of the school age outcomes for infants with only moderately low birthweight (1500-2000 g). This study examines the prevalence of special educational placement and the relationship of such placement to grade retention, verbal and performance scores on tests of general intelligence, reading and maths achievement scores and classroom hyperactivity among low-birthweight children. In a regional birth cohort of 1105 infants born between 1984 and 1987 and weighing 500-2000 g, 868 children were available for follow-up at age nine. Information on special education placement as well as grade retention, intelligence, academic achievement and classroom behaviour was available on 645 (74% completion rate). Nearly a third of the cohort was classified as needing special education. Special education placement followed a birthweight gradient, occurring among 29.3% of children with birthweights 1500-2000 g, among 32.5% in children 1000-1500 g and 49.4% in children < 1000 g. Among children in special education, a similar birthweight gradient was found for maths achievement and hyperactivity, but not for reading achievement or IQ scores. Among children not in special education, only maths achievement showed such a decline with birthweight. A substantial proportion of low-birthweight children, including those of moderate low birthweight, receive special education services, although the need is greatest among those with the lowest birthweights. Maths achievement declined with birthweight regardless of educational placement. The medical and social risk factors that accompany low birthweight and may account for these findings, require further study.

Stability of longitudinal motor development in very low birthweight infants from 5 months to 5.5 years

AIM

The motor performance of 165 very low birthweight (VLBW) infants was assessed prospectively at 5, 10, 18 mo and 5.5 y. The aim of the study was to evaluate longitudinal stability of motor development and its association with birthweight (BW), gestational age at birth, intraventricular haemorrhage (IVH), periventricular leucomalacia (PVL) and retinopathy of prematurity (ROP). Furthermore, at 5.5 y the motor behaviour of the VLBW population was compared with that of 124 children born at term.

METHODS

The results of each examination were ranked into four levels and the stability of motor development was evaluated on the basis of this ranking. At 5.5 y, VLBW children and controls were compared according to percentiles in the Movement ABC.

RESULTS

Fifty-three percent of the VLBW infants displayed a stable motor development. Only PVL and BW contributed significantly to the variability in their motor performance. Forty-seven percent of the infants exhibited an unstable motor development with no association to risk factors. In the entire group only IVH and severe ROP were related to poor motor performance. The majority of the VLBW children performed within the normal range at 5.5 y but their performances were inferior to those of control children.

CONCLUSION

VLBW infants with poor early motor performance and/or severe IVH/PVL and ROP should be recruited into individualized follow-up programmes, whereas regular ongoing monitoring by follow-up may be sufficient for those with normal early motor performance and normal ultrasound findings.

Precursors of mental health problems for low birth weight children: the salience of family environment during the first year of life

The purpose of this study was to determine the contributions of infant characteristics and early family environment to the incidence of emotional and behavioral problems for low birth weight children. Data were collected from ethnically diverse families of 110 children who had a birth weight of less than 2500 grams. Results of stepwise regression analysis indicated that inadequate family income, troubles with family cohesion and adaptability, and an infant's insecure attachment to the mother accounted for 48% of the variance in the incidence of emotional-behavioral problems for children. None of the infants' characteristics, including birth weight, perinatal morbidity, cognitive ability and social competence, entered the regression model. Findings suggest that family environment is a key factor in the low birth weight child's risk for early mental health problems.

Impact of low birth weight on attention-deficit hyperactivity disorder

The objective of the study was to evaluate an association between low birth weight (LBW) and attention-deficit hyperactivity disorder (ADHD) attending to potential family-genetic and environmental confounders. We examined 252 ADHD cases (boys and girls) and 231 non-ADHD controls and their parents. All subjects were extensively assessed with structured diagnostic interviews, cognitive assessments, and structured interviews of prenatal, infancy, and delivery complications. ADHD cases were three times more likely to have been born LBW than were non-ADHD controls, after attending to potential confounders such as prenatal exposure to alcohol and cigarettes, parental ADHD, social class, and comorbid disruptive behavior disorders in parents and offspring. If this association was causal, 13.8% of all ADHD cases could be attributed to LBW. These results converge with prior studies documenting similar associations and indicate that LBW is an independent risk factor for ADHD. Children with LBW, however, make up a relatively small proportion of children with ADHD.

Behaviour problems in extremely low birthweight children at 5 and 8 years of age

This study explored the prevalence and stability of behaviour problems and their prediction from neonatal, medical and family context factors in a group of extremely low birthweight (ELBW) infants assessed at 5 and 8 years of age. Behaviour problems were identified on the basis of several measures: the Total Behaviour Problem Scale and the Adaptive Function Scale of the Child Behaviour Checklist, and the Hyperactivity Index and Hyperactivity Scale from the Conners' Rating Scale. In this group of ELBW infants, the prevalence of behaviour difficulties was somewhat lower than that reported in other studies, and varied according to the measure and informant (parent vs. teacher) used. Also, there was little continuity between those children identified by their parents at 5 years of age as having behaviour problems and those children identified by parent and/or teacher report at 8 years of age. Most of the children identified with behaviour difficulties at 8 years were also reported to have academic difficulties. None of the neonatal or medical factors predicted behaviour difficulties at 8 years of age. In contrast, two family context factors, maternal level of education and family stress, were related to behaviour difficulties at 8 years. These findings indicate that ELBW and the often associated medical complications may not necessarily predispose infants to develop subsequent behaviour difficulties later on in childhood.

Increased risk of learning disabilities in low birth weight boys at age 11 years

BACKGROUND

Few studies have examined learning disabilities among low birth weight (< or =2500 g) children, and those that have, have focused on very low birth weight children (<1500 g). We tested the hypothesis that low birth weight increases the risk of reading and math disabilities, examined possible sex differences in the effect of low birth weight, and assessed risk across the entire range of low birth weight.

METHODS

Low birth weight and normal birth weight children were randomly selected from the 1983-1985 newborn lists of an urban and a suburban hospital in southeast Michigan. Children with neurological impairments were excluded. Children were evaluated at age 6 years and at age 11 years. Of the 823 children in the initial assessment, 717 (87.1%) participated in the second assessment. The Wechsler Intelligence Scale for Children--Revised and the Woodcock-Johnson Psycho-Educational Battery--Revised were used to identify children with learning disabilities. Learning disabilities were estimated in 574 children with IQs of > or =85.

RESULTS

Low birth weight was associated with increased risk for reading and math disability in male children (odds ratio = 3.3 and odds ratio = 6.5, respectively) but not in female children. The increased risk of learning disabilities among male children applied to the entire range of low birth weight and was observed in both the urban and suburban communities.

CONCLUSIONS

The effect of low birth weight on learning disabilities appears to be specific to male children. Although this sex-specific effect is consistent with previous findings of a greater vulnerability of male children to pregnancy and birth complications, it remains to be replicated and clarified.