Intelligence Quotient Deficits Research Articles

Impact of glucose metabolism on the developing brain.

Glucose is the most important substrate for proper brain functioning and development, with an increased glucose consumption in relation to the need of creating new brain structures and connections. Therefore, alterations in glucose homeostasis will inevitably be associated with changes in the development of the Nervous System. Several studies demonstrated how the alteration of glucose homeostasis - both hyper and hypoglycemia- may interfere with the development of brain structures and cognitivity, including deficits in intelligence quotient, anomalies in learning and memory, as well as differences in the executive functions. Importantly, differences in brain structure and functionality were found after a single episode of diabetic ketoacidosis suggesting the importance of glycemic control and stressing the need of screening programs for type 1 diabetes to protect children from this dramatic condition. The exciting progresses of the neuroimaging techniques such as diffusion tensor imaging, has helped to improve the understanding of the effects, outcomes and mechanisms underlying brain changes following dysglycemia, and will lead to more insights on the physio-pathological mechanisms and related neurological consequences about hyper and hypoglycemia.

All day‐long pacifier use and intelligence quotient in childhood: A birth cohort study

Literature on pacifier use remains controversial, but mostly suggests an inverse association with childhood intelligence. The objective of this study was to assess the association between pacifier use and intelligence quotient (IQ) in six-year-old children from a birth cohort. Data from 3532 children from the 2004 Pelotas (Brazil) Birth Cohort were analysed. Children were recruited and assessed at birth and followed up at 3months, and 1, 2, 4, and 6years. Data on pacifier use duration and intensity were obtained via interviews with mothers in all six follow-up visits. IQ was estimated at 6years using the Wechsler Intelligence Scale for Children and standardised for the analyses. Crude and adjusted coefficients were calculated (linear regression) for all the data collected in follow-up assessments for pacifier use. IQ was inversely associated with all pacifier use indicators. Children who used a pacifier all day long (ADL) at any follow-up showed an IQ 0.18 (95% confidence interval [CI] 0.11, 0.24) standard deviations below those who never used it ADL, after adjusting for confounders. The strength of association increased with number of assessments reporting ADL pacifier use, from a reduction in IQ of 0.13 (95% CI 0.06, 0.21) to 0.34 (95% CI 0.15, 0.52) standard deviations for ADL use in one and in all four follow-up visits, respectively. We found a strong association between intense pacifier use up to 4years of age and lower IQ at 6years. A dose-response gradient was observed, with greater IQ deficits in children who used a ADL pacifier for longer durations. The mechanisms underlying this association need to be clarified. One hypothesis is that children using a pacifier, especially those who use it more intensely, are less stimulated.

Association Analysis Between Catechol-O-Methyltransferase Expression and Cognitive Function in Patients with Schizophrenia, Bipolar Disorder, or Major Depression.

IntroductionSchizophrenia, bipolar disorder (BD), and major depressive disorder are three common mental disorders. Although their diagnosis and treatment differ, they partially overlap.MethodsTo explore the similarities and characteristics of these three psychiatric diseases, an intelligence quotient (IQ) assessment was performed to evaluate cognitive deficits. Relative catechol-O-methyltransferase (COMT) expression in peripheral blood mononuclear cells was examined in all three groups compared with healthy controls (HCs).ResultsThe results indicated that patients with any of the three psychiatric diseases presented IQ deficits, and that the first-episode schizophrenia (FES) group had even lower cognitive function than the other two groups. The relative COMT expression decreased in the FES group and increased in the BD group compared with the HC group. The correlation analysis of COMT expression level and IQ scores showed a positive correlation between relative COMT expression and full-scale IQ in the HC group. However, this correlation disappeared in all three psychiatric diseases studied.ConclusionIn conclusion, this cross-disease strategy provided important clues to explain lower IQ scores and dysregulated COMT expression among three common mental illnesses.

Are changes in ADHD course reflected in differences in IQ and executive functioning from childhood to young adulthood?

Attention-deficit hyperactivity disorder (ADHD) is associated with poorer cognitive functioning. We used a developmental, genetically-sensitive approach to examine intelligence quotient (IQ) from early childhood to young adulthood among those with different ADHD courses to investigate whether changes in ADHD were reflected in differences in IQ. We also examined executive functioning in childhood and young adulthood among different ADHD courses. Study participants were part of the Environmental Risk (E-Risk) Longitudinal Twin Study, a population-based birth cohort of 2232 twins. We assessed ADHD in childhood (ages 5, 7, 10 and 12) and young adulthood (age 18). We examined ADHD course as reflected by remission, persistence and late-onset. IQ was evaluated at ages 5, 12 and 18, and executive functioning at ages 5 and 18. ADHD groups showed deficits in IQ across development compared to controls; those with persistent ADHD showed the greatest deficit, followed by remitted and late-onset. ADHD groups did not differ from controls in developmental trajectory of IQ, suggesting changes in ADHD were not reflected in IQ. All ADHD groups performed more poorly on executive functioning tasks at ages 5 and 18; persisters and remitters differed only on an inhibitory control task at age 18. Differences in ADHD course - persistence, remission and late-onset - were not directly reflected in changes in IQ. Instead, having ADHD at any point across development was associated with lower average IQ and poorer executive functioning. Our finding that individuals with persistent ADHD have poorer response inhibition than those who remitted requires replication.

Cognitive function in children with classic congenital adrenal hyperplasia.

Studies of cognitive function in patients with congenital adrenal hyperplasia (CAH) are few and controversial. This study aimed to investigate general intelligence and specific cognitive functions in children with salt wasting (SW) form of CAH and their relationship to demographic, clinical, and laboratory variables. This study included 36 children with classic 21 hydroxylase deficiency SW type of CAH (males = 12; females = 24; mean age = 15.6 ± 2.3years). Intelligence quotient (IQ) and cognition were assessed using Wechsler Intelligence Scale for Children 3rd edition (WISC-III) and Stanford Binet Subsets Test version 4 (SBST4). Compared to controls, patients had lower mean full-scale (FS) IQ (P = 0.01) score, particularly performance IQ score (P = 0.001), and comprehension, pattern analysis, quantitation, bead memory, and memory for sentences of SBST4 (P = 0.05, P = 0.014, P = 0.001, P = 0.002, and P = 0.05, respectively). Lower IQ was observed in poorly controlled compared with well-controlled patients on medical treatment. Significant correlations were observed between FSIQ with age (r = - 0.810; P = 0.001), duration of treatment (r = - 0.887; P = 0.01), dose of glucocorticoids (r = - 0.463; P = 0.01), 17-OHP (r = - 0.543; P = 0.01) and testosterone (r = - 0.462; P = - 0.006) levels, and number of hyponatremic episodes (r = - 0.350; P = 0.05). In multivariate analysis, the independent risks of low FSIQ were the dose of glucocorticoids (OR = 1.14; 95% CI = 1.08-1.23, P = 0.0001), 17-OHP levels (OR = 2.25; 95% CI = 1.19-2.85, P = 0.01), and number of hyponatremic episodes (OR = 4.34; 95% CI = 2.05-5.15, P = 0.01).Conclusion: Patients with SW form of CAH may have lower IQ and cognitive deficits which may be related to the dose of glucocorticoids, androgen excess, and number of hyponatremic episodes. What is Known: • Congenital adrenal hyperplasia (CAH) is a group of inherited impairment of cortisol biosynthesis. • Studies of cognitive function in patients with congenital adrenal hyperplasia (CAH) are few and controversial. What is New: • Children with CAH may have lower intelligent quotient (IQ) and cognitive deficits. • Early hyponatremic episodes, overtreatment with glucocorticoids, and high androgen levels may be possible causative factors for the cognitive deficits.

Parental education accounts for variability in the IQs of probands with Down syndrome: A longitudinal study.

Recent work has demonstrated that variability in probands' phenotypes, including physical features, cognitive abilities, social functioning, and other developmental domains, is influenced by parental traits. Here we examine the role of parental education as a factor contributing to the variability of intelligence quotient (IQ) of offspring with trisomy 21. Participants were 43 probands with trisomy 21, aged 4-21 years of age, and their parents. Data were collected on parental education, and a bi-parental mean education score (BMES) was calculated. Probands' cognitive abilities were assessed by the Stanford-Binet 4th edition at baseline (T1), and again 24 months later (T2). Probands were placed into one of two age groups: 4-12 years and 13-21 years. Results indicated higher parent-proband correlations in Age Group 2 (mean r = .47) relative to Age Group 1 (mean r = .33) and increasing parent-proband correlations across time, with mean correlations of Age Group 1, T1: r = .26, T2: 39; Age Group 2 T1: r = .49, T2: r = 46. Despite the expected IQ deficits observed in trisomy 21 probands, parental education may still contribute to the variability of probands' cognitive abilities. These findings are consistent with the literature noting increasing heritability of IQ with development.

The relationship between brain volumes and intelligence in bipolar disorder

ObjectivesBipolar disorder type-I (BD-I) patients show a lower Intelligence Quotient (IQ) and smaller brain volumes as compared with healthy controls. Considering that in healthy individuals lower IQ is related to smaller total brain volume, it is of interest to investigate whether IQ deficits in BD-I patients are related to smaller brain volumes and to what extent smaller brain volumes can explain differences between premorbid IQ estimates and IQ after a diagnosis of BD-I. MethodsMagnetic resonance imaging brain scans, IQ and premorbid IQ scores were obtained from 195 BDI patients and 160 controls. We studied the relationship of (global, cortical and subcortical) brain volumes with IQ and IQ change. Additionally, we investigated the relationship between childhood trauma, lithium- and antipsychotic use and IQ. ResultsTotal brain volume and IQ were positively correlated in the entire sample. This correlation did not differ between patients and controls. Although brain volumes mediated the relationship between BD-I and IQ in part, the direct relationship between the diagnosis and IQ remained significant. Childhood trauma and use of lithium and antipsychotic medication did not affect the relationship between brain volumes and IQ. However, current lithium use was related to lower IQ in patients. ConclusionsOur data suggest a similar relationship between brain volume and IQ in BD-I patients and controls. Smaller brain volumes only partially explain IQ deficits in patients. Therefore, our findings indicate that in addition to brain volumes and lithium use other disease factors play a role in IQ deficits in BD-I patients.

369 - Exploration for Sub-Clinical Correlates of Neurotoxicity in Mining Communities in Nigeria: An Urgent National Priority

Background Recent reports indicate that there is increasing exposure to neurotoxicants, particular lead and probably mercury in mining communities in Nigeria. The lingering Zamfara lead poisoning and that in Minna remain fresh in our memories. Attention has only been paid to the dramatic clinical manifestations such as encephalopathy that are readily discernible. Long-term sub-clinical effects; often cumulative and more serious sequelae are often ignored. This paper examines these issues. Comments Neurotoxicity is a severe clinical entity well recognized in mining communities where precious metals such as gold, diamond and others are mined. These precious metals often occur in the same ores, contaminated by toxic metals such as lead, arsenic or mercury that may be used to refine gold. Cells of the nervous system have high energy demand, which may not be adequate in poor rural communities with attendant malnutrition, raising susceptibility. Importantly the mode by which nerve impulse is transmitted chemically across extracellular space is particularly at risk from toxicants. The low functional reserve of the nervous system; inability to regenerate makes it important to prevent any neuronal death, as excess loss of neurons may lead to dementia in later life, probably corroborating Barker’s hypothesis. Children are recognized to be more susceptible to neurotoxicants that may culminate in deficits in intelligence quotient (IQ). These appear to argue for the need to explore for sub-clinical correlates including nutritional deficits and biochemical derangements, key among which are perturbed calcium homeostasis, neurooxidative stress; the neurobiological mechanisms that may also serve as early markers of neurotoxicity. Conclusion Neurotoxicity has a number of adverse health outcomes and reduced productivity that should be prevented, particularly now that Nigeria is broadening her revenue base. The mining sector is receiving a disproportionate attention; making exploration for sub-clinical correlates of neurotoxicity in the growing mining communities a national priority.

Modifying effect of COMT gene polymorphism and a predictive role for proteomics analysis in children's intelligence in endemic fluorosis area in Tianjin, China.

Cumulative fluoride exposure has adverse influences on children's intelligence quotient (IQ). In addition, catechol-O-methyltransferase (COMT) gene Val158Met polymorphism (rs4680) is associated with cognitive performance. This study aimed to evaluate the associations of COMT polymorphism and alterations of protein profiles with children's intelligence in endemic fluorosis area. We recruited 180 schoolchildren (10-12 years old) from high fluoride exposure (1.40 mg/l) and control areas (0.63 mg/l) in Tianjin City, China. The children's IQ, fluoride contents in drinking water (W-F), serum (S-F), and urine (U-F); serum thyroid hormone levels, COMT Val158Met polymorphism, and plasma proteomic profiling were determined. Significant high levels of W-F, S-F, U-F, along with poor IQ scores were observed in the high fluoride exposure group compared with those in control (all P < 0.05). S-F and U-F were inversely related with IQ (r(s) = -0.47, P < 0.01; r(s) = -0.45, P = 0.002). Importantly, higher fluoride exposure was associated with steeper cognitive decline among children with the reference allele Val compared with those homozygous or heterozygous for the variant allele Met (95% CI, -16.80 to 2.55; P interaction < 0.01). Additionally, 5 up-regulated protein spots related to cell immunity and metabolism were detected in children with high fluoride exposure compared with the control. In conclusion, fluoride exposure was adversely associated with children's intelligence, whereas the COMT polymorphism may increase the susceptibility to the deficits in IQ due to fluoride exposure. Moreover, the proteomic analysis can provide certain basis for identifying the early biological markers of fluorosis among children.

Malformaciones del desarrollo cortical en pacientes adultos con epilepsia: serie de 79 casos

Malformations of cortical development (MCD) are an important cause of epilepsy, delayed psychomotor development or neurological deficits. AIM. To report on the long-term clinical course and differential characteristics of several groups of MCD in adults with epilepsy. Our sample consisted of patients over 16 years of age with MCD confirmed by magnetic resonance imaging, and epilepsy. The characteristics of the epilepsy, presence of neurological deficits, intellectual disability, history of perinatal pathology and electroencephalogram recordings were analysed. The patients were classified into three groups (G) in accordance with the Barkovich classification. A total of 85 patients with MCD were identified from 2630 patients with epilepsy and 79 of them were finally included in the sample. Mean age: 37 years, 57% were females. Mean age at onset of the crises: 17.8 years, and 59.5% were medication resistant. The distribution of the cases according to the Barkovich classification was: G1 (alterations affecting neuronal proliferation): 59.5%; G2 (alterations affecting migration): 25.3%; and G3 (alterations affecting cortical organisation): 15.2%. Focal neurological deficit was observed in 19% and 34.2% had an intelligence quotient < 80. On analysing by groups, G3 was found to display a higher percentage of focal neurological and intelligence quotient deficits than G1 and G2 (p < 0.05). Patients with MCD in G3 are more likely to have neurological deficit, intellectual disability and better control over their crises than patients from G1 and G2, most of whom present refractory epilepsy.

Latent class analysis of reading, decoding, and writing performance using the Academic Performance Test: concurrent and discriminating validity

AimTo explore and validate the best returned latent class solution for reading and writing subtests from the Academic Performance Test (TDE).SampleA total of 1,945 children (6–14 years of age), who answered the TDE, the Development and Well-Being Assessment (DAWBA), and had an estimated intelligence quotient (IQ) higher than 70, came from public schools in São Paulo (35 schools) and Porto Alegre (22 schools) that participated in the ‘High Risk Cohort Study for Childhood Psychiatric Disorders’ project. They were on average 9.52 years old (standard deviation = 1.856), from the 1st to 9th grades, and 53.3% male. The mean estimated IQ was 102.70 (standard deviation = 16.44).MethodsVia Item Response Theory (IRT), the highest discriminating items (‘a’>1.7) were selected from the TDE subtests of reading and writing. A latent class analysis was run based on these subtests. The statistically and empirically best latent class solutions were validated through concurrent (IQ and combined attention deficit hyperactivity disorder [ADHD] diagnoses) and discriminant (major depression diagnoses) measures.ResultsA three-class solution was found to be the best model solution, revealing classes of children with good, not-so-good, or poor performance on TDE reading and writing tasks. The three-class solution has been shown to be correlated with estimated IQ and to ADHD diagnosis. No association was observed between the latent class and major depression.ConclusionThe three-class solution showed both concurrent and discriminant validity. This work provides initial evidence of validity for an empirically derived categorical classification of reading, decoding, and writing performance using the TDE. A valid classification encourages further research investing correlates of reading and writing performance using the TDE.

Longitudinal Investigation of Adaptive Functioning Following Conformal Irradiation for Pediatric Craniopharyngioma and Low-Grade Glioma

Children treated for brain tumors with conformal radiation therapy experience preserved cognitive outcomes. Early evidence suggests that adaptive functions or independent-living skills may be spared. This longitudinal investigation prospectively examined intellectual and adaptive functioning during the first 5 years following irradiation for childhood craniopharyngioma and low-grade glioma (LGG). The effect of visual impairment on adaptive outcomes was investigated. Children with craniopharyngioma (n=62) and LGG (n=77) were treated using conformal or intensity modulated radiation therapy. The median age was 8.05 years (3.21-17.64 years) and 8.09 years (2.20-19.27 years), respectively. Serial cognitive evaluations including measures of intelligence quotient (IQ) and the Vineland Adaptive Behavior Scales (VABS) were conducted at preirradiation baseline, 6 months after treatment, and annually through 5 years. Five hundred eighty-eight evaluations were completed during the follow-up period. Baseline assessment revealed no deficits in IQ and VABS indices for children with craniopharyngioma, with significant (P<.05) longitudinal decline in VABS Communication and Socialization indices. Clinical factors associated with more rapid decline included females and preirradiation chemotherapy (interferon). The only change in VABS Daily Living Skills correlated with IQ change (r=0.34; P=.01) in children with craniopharyngioma. Children with LGG performed below population norms (P<.05) at baseline on VABS Communication, Daily Living Indices, and the Adaptive Behavior Composite, with significant (P<.05) longitudinal decline limited to VABS Communication. Older age at irradiation was a protective factor against longitudinal decline. Severe visual impairment did not independently correlate with poorer adaptive outcomes for either tumor group. There was relative sparing of postirradiation functional outcomes over time in this sample. Baseline differences in functional abilities before the initiation of irradiation suggested that other factors influence functional outcomes above and beyond the effects of irradiation.

An Examination of the Impact of Attention-Deficit Hyperactivity Disorder on IQ: A Large Controlled Family-Based Analysis

Although children with attention-deficit hyperactivity disorder (ADHD) have, on average, lower intelligence quotient (IQ) scores than control subjects, the reasons for these deficits remain unknown. Because IQ is highly familial, we investigated whether children with ADHD have a decrement in IQ from expectations based on parental IQ. Subjects were 276 children with ADHD and 239 control subjects of similar age and sex. Expected IQ was calculated based on biological parents' estimated IQ. A significant discrepancy between observed and expected estimated IQ was defined by a child scoring 15 IQ points or more lower than expected, based on parental IQ. Compared with control subjects, children with ADHD were significantly more likely to have lower than expected estimated IQ scores based on parental IQ, though this finding was accounted for by a small subgroup of children with ADHD who had an IQ 15 points or more lower than expected, based on parental IQ. These children were more likely to be female, have higher psychopathological, neuropsychological, educational, and interpersonal deficits, as well as higher rates of perinatal complications. Group differences in IQ scores between children with and without ADHD reported in the literature may be accounted for by a subgroup of children with ADHD who have a large decrement in IQ from expectations based on parental IQ. Although perinatal complications may explain these findings, more work is needed to better understand the etiology of these IQ deficits.

IQ and Blood Lead Levels: Effect Modification By ALAD Amongst Children in Chennai, India

PP-31-171 Background/Aims: Exposure to lead is known to be causally associated with deficits in intelligence quotient (IQ) among children. However, little is known about genetic factors that affect neurocognitive susceptibility to lead. The effect of lead on the body has been known to vary across the aminolevulinate delta-dehydratase (ALAD) genotype among adults, but there are few studies examining the association in children. This study tests the hypothesis that the ALAD polymorphism modifies the association between lead and IQ among school-age children in Chennai, India. Methods: A total of 756 children, aged 3 to 7 years, were recruited from 12 schools in Chennai, India. Blood lead levels (BLL) were measured using the LeadCare Analyzer. The Binet–Kamat intelligence test was administered to ascertain IQ. ALAD genotype, for 695 children, was determined using the MassARRAY iPLEXTM. Stratified and interaction generalized linear models were used to explore modification of the lead and IQ association by ALAD genotype (1/1 vs. 1/2 + 2/2 genotypes) after adjusting for age, socioeconomic status, mother's and father's education, and hemoglobin. Results: The distribution of the ALAD 1/1, ALAD 1/2, and ALAD 2/2 genotype in this population was 73.4%, 23.2%, and 3.4%, respectively. The mean BLL for the whole population was 11.5 μg/dL. Children with the ALAD 1/1 genotype experienced a 3.11 reduction in IQ points with every 10 μg/dL increase in blood lead levels (P = 0.022). Children with the ALAD 1/2 or 2/2 genotype experienced a 1.72 drop in IQ points with every 10 μg/dL increase in BLLs (P = 0.4603). In the interaction model, IQ decreased by 0.698 points between the ALAD groups, with every 10 μg/dL increase in blood lead levels (P = 0.788). Conclusion: This study did not find significant effect modification of the lead and IQ association by ALAD genotype.

Hemoglobin, Lead Exposure, and Intelligence Quotient: Effect Modification by the DRD2 Taq IA Polymorphism

BackgroundAnemia and lead exposure remain significant public health issues in many parts of the world, often occurring together. Animal studies suggest that the dopamine D2 receptor (DRD2) mediates the effects of both lead and iron on cognition and behavior.ObjectiveWe tested the hypothesis that the DRD2 Taq IA polymorphism modifies the effects of lead and hemoglobin on intelligence quotient (IQ) among children.MethodsBlood lead and hemoglobin were assessed in 717 children 3–7 years of age attending 12 schools in Chennai, India. IQ was determined using the Binet-Kamat scales of intelligence. Genotyping for the DRD2 polymorphism was carried out using a MassARRAY iPLEX platform. Stratified analyses and interaction models, using generalized estimating equations (GEEs), were used to explore interactions between lead and hemoglobin, and DRD2 Taq IA categories [homozygous variant (A1) vs. presence of wild-type allele (A2)].ResultsAfter we controlled for potential confounders, a one-unit increase in log blood lead was associated with a decrease of 9 IQ points [95% confidence interval (CI), −18.08 to −0.16] in the homozygous-variant children (n = 73) compared with a decrease of 4 IQ points (95% CI, −7.21 to −0.69) among those with the wild-type allele (n = 644). Higher hemoglobin levels were associated with higher IQ in the children who carried the wild-type allele DRD2, but in children homozygous for the variant allele, an increase of 1 g/dL hemoglobin was associated with a decrease in 1.82 points of IQ (95% CI, −5.28 to 1.64; interaction term p-value = 0.02).ConclusionThe results of this study suggest that the DRD2 Taq IA polymorphism disrupts the protective effect of hemoglobin on cognition and may increase the susceptibility to the deficits in IQ due to lead exposure.

Children With Congenital Hypothyroidism: Long-Term Intellectual Outcome After Early High-Dose Treatment

We aim to determine long-term intellectual outcome of adolescents with early high-dose treated congenital hypothyroidism (CH). Sixty-three prospectively followed children with CH were assessed at age of 14 y with the Wechsler Intelligence Scale for Children-Revised and compared with 175 healthy controls. Median age at onset of treatment was 9 d (range 5-18 d) and median starting dose of levothyroxine (L-T4) was 14.7 microg/kg/d (range 9.9-23.6 microg/kg/d). Full-scale intelligence quotient (IQ) was significantly lower than in controls after adjustment for socioeconomic status (SES) and gender (101.7 versus 111.4; p < 0.0001). Children with athyreosis had a lower performance IQ than those with dysgenesis (adjusted difference 7.6 IQ scores, p < 0.05). Lower initial thyroxine (T4) levels correlated with poorer IQ (r = 0.27, p = 0.04). Lower SES was associated with poorer IQ, in particular in children with CH (interaction, p = 0.03). Treatment during childhood was not related to IQ at age 14 y. Adolescents with CH manifest IQ deficits when compared with their peers despite early high-dose treatment and optimal substitution therapy throughout childhood. Those adolescents with athyreosis and lower SES are at particular risk for adverse outcome. Therefore, early detection of intellectual deficits is mandatory in children with CH.

Prenatal tobacco smoke and postnatal secondhand smoke exposure and child neurodevelopment

To review the recent scientific literature examining the association of prenatal tobacco and postnatal secondhand smoke exposure and child neurodevelopment. Low birth weight and decreased in-utero brain growth are two of multiple potential etiologic pathways proposed as mediating the effects of prenatal tobacco smoke exposure on child neurodevelopment. These negative effects of prenatal exposure have been consistently demonstrated in animal models, and in humans have been found as early as the newborn period. The literature on both prenatal and postnatal exposure is remarkably consistent in showing associations with increased rates of behavior problems, including irritability, oppositional defiant behavior, conduct disorders and attention deficit hyperactivity disorder. A more rudimentary literature also suggests deficits in intelligence quotient. Recent studies have focused on elucidating the complex interaction among tobacco exposure, genetics and environmental factors. Questions still remain about the relative roles of prenatal vs. postnatal exposure and the potential role of genetic and social confounders, limiting the ability to infer a causal nature to these associations at this time. The consistency of findings across studies is, however, highly suggestive of a causal relationship between environmental tobacco exposure and adverse behavioral and cognitive outcomes in children. Prenatal tobacco and postnatal secondhand smoke exposure is consistently associated with problems in multiple domains of children's neurodevelopment and behavior.

Nutritional status of mentally retarded children in north‐west Spain. I. Anthropometric indicators

To evaluate the nutritional status of mentally retarded children in the region of Galicia in north-west Spain, on the basis of anthropometric variables. The following variables were determined in a sample of 128 mentally retarded children (81 M, 47 F): birthweight, bodyweight, height/length, head circumference, mid-arm circumference, mid-arm muscle circumference, triceps skinfold thickness, subscapular skinfold thickness, arm area, arm muscle area, arm fat area, arm lean-to-fat ratio, Shukla's nutrition index and Quetelet's body mass index (BMI). A preliminary statistical analysis indicated that most information content could be maintained considering only eight of these variables. A factor analysis of the resulting 8 x 128 (variables by subjects) data matrix was performed, identifying two factors (FA1 and FA2) that together explained 82% of total variance. Taking these factors as indicators of nutritional status, the data were analysed for possible effects of age, gender, socioeconomic and family environment, intelligence quotient (IQ), presence/absence of cerebral palsy, quality of diet, appetite and antiepileptic use. The analysis suggested that most subjects were in the normal nutrition range, but about 33% showed either borderline or definite malnutrition. Mean score on FA2 showed a significant negative correlation with age. Children with cerebral palsy had lower mean scores on both factors, and scores on both factors varied with IQ. Children with definite malnutrition had a significantly lower IQ than those in the normal nutrition range. Mean score on both factors varied with appetite and quality of diet. The mean FAI score of children from inland-rural areas was significantly lower than that of children from coastal or urban areas. Mean FA1 score increased with increasing age of the parents. The prevalence of obesity was 13% when obesity was defined on the basis of Shukla's nutrition index, and 19% when defined on the basis of FA1 score. Malnutrition as revealed by anthropometric variables occurs with a high prevalence among mentally retarded children. The prevalence increases with age, increasing IQ deficit and cerebral palsy.

Nutritional status of mentally retarded children in north-west Spain. I. Anthropometric indicators

Aim: To evaluate the nutritional status of mentally retarded children in the region of Galicia in north-west Spain, on the basis of anthropometric variables. Methods: The following variables were determined in a sample of 128 mentally retarded children (81 M, 47 F): birth weight, body weight, height/length, head circumference, mid-arm circumference, mid-arm muscle circumference, triceps skinfold thickness, subscapular skinfold thickness, arm area, arm muscle area, arm fat area, arm lean-to-fat ratio, Shukla's nutrition index and Quetelet's body mass index (BMI). A preliminary statistical analysis indicated that most information content could be maintained considering only eight of these variables. A factor analysis of the resulting 8 × 128 (variables by subjects) data matrix was performed, identifying two factors (FA1 and FA2) that together explained 82% of total variance. Taking these factors as indicators of nutritional status, the data were analysed for possible effects of age, gender, socioeconomic and family environment, intelligence quotient (IQ), presence/absence of cerebral palsy, quality of diet, appetite and antiepileptic use. Results: The analysis suggested that most subjects were in the normal nutrition range, but about 33% showed either borderline or definite malnutrition. Mean score on FA2 showed a significant negative correlation with age. Children with cerebral palsy had lower mean scores on both factors, and scores on both factors varied with IQ. Children with definite malnutrition had a significantly lower IQ than those in the normal nutrition range. Mean score on both factors varied with appetite and quality of diet. The mean FA1 score of children from inland-rural areas was significantly lower than that of children from coastal or urban areas. Mean FA1 score increased with increasing age of the parents. The prevalence of obesity was 13% when obesity was defined on the basis of Shukla's nutrition index, and 19% when defined on the basis of FA1 score. Conclusion: Malnutrition as revealed by anthropometric variables occurs with a high prevalence among mentally retarded children. The prevalence increases with age, increasing IQ deficit and cerebral palsy.

Societal costs of exposure to toxic substances: economic and health costs of four case studies that are candidates for environmental causation.

Four outcomes that evidence suggests are candidates for "environmental causation" were chosen for analysis: diabetes, Parkinson's disease (PD), neurodevelopmental effects and hypothyroidism, and deficits in intelligence quotient (IQ). These are an enormous burden in the United States, Canada, and other industrial countries. We review findings on actual social and economic costs, construct estimates of some of the costs from pertinent sources, and provide several hypothetical examples consistent with published evidence. Many detailed costs are estimated, but these are fragmented and missing in coverage and jurisdiction. Nonetheless, the cumulative costs identified are very large, totaling $568 billion to $793 billion per year for Canada and the United States combined. Partial Canadian costs alone are $46 billion to $52 billion per year. Specifics include diabetes (United States and Canada), $128 billion per year; PD in the United States, $13 billion to $28.5 billion per year; neurodevelopmental deficits and hypothryoidism are endemic and, including estimates of costs of childhood disorders that evidence suggests are linked, amount to $81.5 billion to $167 billion per year for the United States and $2 billion per year in Ontario; loss of 5 IQ points cost $30 billion per year in Canada and $275 billion to $326 billion per year in the United States; and hypothetical dynamic economic impacts cost another $19 billion to $92 billion per year for the United States and Canada combined. Reasoned arguments based on the weight of evidence can support the hypothesis that at least 10%, up to 50% of these costs are environmentally induced--between $57 billion and $397 billion per year.